Mechanical compressor

Abstract

Compression mechanisms for a mechanical compression pulse spray dryer or a separation device are disclosed. The first mechanism comprises a cylinder block 500 with a piston 506 slidably mounted within

Description

A known objective is to extract a fluid from a solution comprising the fluid with dissolved solids. One type of such fluid with dissolved solids is a saline solution such as salt water (i.e. salt dissolved within water) such as sea water (i.e. sodium chloride dissolved in water). A well-known desire is to produce drinking water from sea water. WO23161599 and GB2619110 both disclose devices which are capable of desalinating sea water which comprises mechanical compressors. One type of mechanical compressor which can be used in these devices is a piston compressor. A problem with existing designs of desalination apparatus (in particular, for the extraction of drinkable water from sea water) is that they are complex in their construction and are expensive to operate. Often, the apparatus requires constant monitoring and regular servicing by trained personnel using specific service parts. Such apparatus can utilise a number of different types of desalination technology, such as, solar distillation, natural evaporation, vacuum distillation, thermal distillation, multi-stage flash distillation, multiple-effect distillation, vapor-compression distillation, wave-powered distillation, membrane distillation, forward and reverse osmosis, freeze-thaw desalination and electrodialysis membranes. Typically, such apparatus is constructed to operate on an industrial scale. Whilst that is advantageous for providing drinking water for a large population, such as a town or a city, it is often not practical for use in situations where a small-scale operation is required, such as on a farm. Many known solutions for desalination focus on the efficiency of the system i.e. the amount of energy put in versus the amount of desalinated water extracted. This leads to complex solutions. Again, whilst this may be acceptable on apparatus used on an industrial scale, it hinders the use of such apparatus in small operations, especially where the personnel operating such apparatus are often not trained to use such apparatus and the operation of such apparatus is not the personnel's primary function. WO23161599 discloses a mechanical compression pulse spray dryer which is capable of being used as a desalination device. GB2619110 discloses a separation device which is also capable of being used as a desalination device. The devices disclosed in WO23161599 and GB2619110 are either predominantly mechanical devices or purely mechanical devices. Predominantly or purely mechanical devices are easy and cheap to construct and operate. Such designs can also be made small for use in small scale operations. It is desirable to minimise the number of component parts, thus providing reliability and minimising the need for repair. However, the mechanical compressors disclosed in WO23161599 and GB2619110 use valves which are complex in construction or are electrically driven. Such valves are constructed using multiple component parts which are in addition to the component parts of the compression mechanism. The present invention provides a mechanical compressor capable of providing pulses of hot compressed gas which are capable of being used in the mechanical compression pulse spray dryers disclosed in WO23161599, and in particular, in the first embodiment of the mechanical compression pulse spray dryers disclosed in WO23161599 described with reference to Figures 4Ato 4D, and / or the separation devices disclosed in GB2619110, and in particular, in the first embodiment of the separation devices disclosed in GB2619110 described with reference to Figures 4A to 4D. A "mechanical compressor" shall be understood to mean a device which comprises a compression mechanism by which a gas is compressed and at least one valve which allows the gas to enter the compression mechanism and to exit the compression mechanism, once compressed and heated, in a series of pulses. The present invention enables the number of component parts to be minimised, thus providing reliability and minimising the need for repair. It achieves this by using the same component parts of the compression mechanism to form the valves. For example, in the first embodiment of the mechanical compression pulse spray dryers disclosed in WO23161599 described with reference to Figures 4A to 4D and in the first embodiment of the separation devices disclosed in GB2619110 described with reference to Figures 4A to 4D, the compression mechanism comprises a piston slidable mounted within a cylinder. The present invention provides a mechanical compressor where the piston and cylinder of the compression mechanism also form all of the valves of the mechanical compressor, the movement of the piston within the cylinder both compressing the gas and opening and dosing the valves of the compression mechanism. Furthermore, the movement of the piston within the cylinder also acts as the timing device for opening and closing the valves at the appropriate point in time, the valves being open and closed dependent on the position of the piston within the cylinder. The present invention provides a mechanical compressor capable of providing pulses of hot compressed gas where, when the compression mechanism comprises a shaped housing in which is rotatably mounted, in an eccentric manner, a triangular rotor, in the same manner as a Wankel engine, the rotor and shaped housing form the compression mechanism, which also forms all of the valves of the mechanical compressor, the movement of the rotor within the shaped housing both compressing the gas and opening and closing the valves of the compression mechanism, the movement of the rotor within the shaped housing acting as the timing device for opening and closing the valves. Prior Art Five pieces of relevant prior art will now be briefly described. The first four will be described with reference to Figures 1 to 4 in both WO23161599 and GB2619110, the first two providing technology which can be utilised to desalinate water, the third which utilises piston compression to heat a gas and the fourth which discloses the use of a mechanical compressor for a separation device or a mechanical compression pulse spray dryer. The fifth utilises rotary compression to heat a gas and will be described with reference to US2988065. The first piece of prior art is a spray drying apparatus will now be described with reference to Figures 1 of WO23161599 and GB2619110. Spray drying is commonly used in the production of food stuffs or pharmaceuticals for the extraction of solids from a fluid. Examples of solids are salts or chemicals dissolved in the fluid or a powdered solid suspended in the fluid. The solids are extracted from the fluid by, first, atomizing the fluid containing the solid by passing it through an atomizer and then, second, spraying the atomised fluid and solids into a hot drying gas medium, for example, air. The atomised fluid is then rapidly evaporated and subsequently separated from the solids. The solids are then collected. The evaporated fluid can then be condensed to form a liquid again. The spray drying process provides a rapid, continuous, cost-effective, reproducible and scalable process for the extraction of solids from a fluid. Such a process can be utilised to separate salt from water in which it is dissolved and as such, can be used to desalinate sea water. Figures 1 of WO23161599 and GB2619110 show a schematic diagram of a spray drying apparatus to show the basic principles of the construction of the spray drying apparatus. Referring to Figures 1 of WO23161599 and GB2619110, the spray drying apparatus comprises a tank 100 (using the reference numbers of WO23161599 and GB2619110) in which is inserted the fluid 102 containing the solids. A first; pipe 104 connects the tank 100 to a pump 106. A second pipe 108 connects the pump 106 to a housing 110 which forms a mixing chamber 112. The second pipe 108 passes through the wall of the housing 110 and extends into the mixing chamber 112. A nozzle 114 is attached to the end of the second pipe 108 inside of the mixing chamber 112. An air pump 116 is attached to a third pipe 118. The third pipe 118 connects between the air pump 116 and an air heater 120. A fourth pipe 122 attaches between the air heater 120 and the housing 110 of the mixing chamber 112, the end of the fourth pipe 122 connecting to an aperture 124 formed through the wall of the housing 110. A fifth pipe 126 attaches between the housing 110 of the mixing chamber 112 and a cyclonic separator 128, one end of the fifth pipe 126 connecting to an aperture 127 formed through the wall of the housing 110, the other end of the fifth pipe 126 connecting to an aperture 125 formed through the wall of the cyclonic separator 128. The cyclonic separator 128 has a separation chamber 130 which tapers at its lower end to a sixth solids exit pipe 132. A seventh vapour exit pipe 134 connects to an aperture 136 formed through an upper part of the wall of the cyclonic separator 128. The operation of the spray drying apparatus will now be described. In use, the air pump 116 sucks in air from the surrounding atmosphere into the third pipe 118. The air is blown through the third pipe 118 and into the air heater 120. The air passes through the air heater 120 where it is heated to a high temperature. The heated air is then blown through the fourth pipe 122, through the aperture 124 and into the mixing chamber 112. The tank 100 is filled with a fluid 102 containing the solids (such as sea water). The fluid 102 containing the solids then flows into the pump 106. The pump 106 then pumps the fluid 102 with the solids at high pressure through the second pipe 108 and the nozzle 114 and into the mixing chamber 112. As the fluid 102 with the solids passes through the nozzle 114, the fluid 102 is atomized into a spray 138. The spray 138 mixes with the heated air where it is rapidly heated, the fluid 138 vaporising as it does so. The vaporised fluid 102 and solids then pass out of the mixing chamber 112 through the fifth pipe 126 and into the separating chamber 130 where it is rotated rapidly to cyclonically separate the solids from the vaporised fluid 102. The solids then exit the separation chamber 130 through the sixth solids exit pipe 132. The vaporised fluid 102 then exits the separation chamber 130 through the seventh vapour exit pipe 134 where the vaporised fluid 102 can be cooled to return it to a liquid. The spray drying apparatus described with reference to Figures 1 of WO23161599 and GB2619110 is a co-current spray dryer. Another type of spray dryer is a counter-current spray dryer. The second piece of prior art is a pulse combustion spray dryer which will now be described with reference to Figures 2 of WO23161599 and GB2619110. Figure 2 shows a schematic diagram of a pulse combustion spray dryer to show the basic principles of the construction of the pulse combustion spray dryer. A pulse combustion spray dryer comprises a pulse combustor which produces a series of pulses of hot exhaust gases and a pulse spray dryer. Referring to Figures 2 of WO23161599 and GB2619110 (using the reference numbers of WO23161599 and GB2619110), the pulse spray dryer comprises a tank (not shown) in which is inserted the fluid containing the solids. A first pipe 204 connects the tank to a pump 206. A second pipe 208 connects the pump 206 to a housing 210 which forms a mixing chamber 212. The second pipe 208 passes through the wall of the housing 210 and extends into the mixing chamber 212. A nozzle 214 is attached to the end of the second pipe 208 inside of the mixing chamber 212. Mounted on top of the housing 210 is a pulse combustor 250 comprising an inner wall 252 and an outer wall 254. The inner wall 252 forms a combustion chamber 256. The combustion chamber 256 is connected to the mixing chamber 212 via a third pipe 258. Mounted on the top on the inner wall 252 is a valve 260. The top of the valve 260 is connected to a fourth pipe 262 through which a combustible fuel is fed into the valve 260. An air filter 264 is connected to an air pump 216 via a fifth pipe 266. The air pump 116 is attached to a sixth pipe 218. The sixth pipe 218 connects between the air pump 216 and the outer wall 254. When the air pump 216 is activated, air is drawn from the environment into the filter 264, through the fifth pipe 266, through the air pump 216, through the sixth pipe 218 and into a separation chamber 268 formed between the inner wall 252 and the outer wall 254. Air in the separation chamber 268 is in direct contact with side of and capable of being drawn into the valve 260. The valve 260 injects a mixture of the combustible fuel and air into the combustion chamber 256 at pre-determine time intervals. Mounted inside the combustion chamber 256 is a spark plug (not shown) or some other type of ignition device. After the valve 260 injects a mixture of the combustible fuel and air into the combustion chamber 256 at pre-determine time intervals, the spark plug ignites the fuel / air mixture inside of the combustion chamber 256. The pulse spray dryer further comprises a seventh pipe 226 which attaches between the housing 210 of the mixing chamber 212 and a cyclonic separator 228, one end of the seventh pipe 126 connecting to an aperture formed through the base wall of the housing 210, the other end of the seventh pipe 226 connecting to an aperture formed through the wall of the cyclonic separator 228. The cyclonic separator 228 has a separation chamber 230 which tapers at its lower end to an eighth solids exit pipe 232. A ninth vapour exit pipe 234 connects to an aperture formed through an upper part of the wall of the cyclonic separator 228 to an aperture formed through a lower part of a wall of a condenser 270. The condenser 270 forms a condensing chamber 272 which has a tapered section 274 at its lower end where it connects to a tenth liquid exits pipe 276. An eleventh air exit pipe 278 connects between the top of the condenser 270 and an exit fan 280. A twelfth pipe 282 connects between the exit fan and an exhaust duct 284. The operation of the pulse combustion spray dryer will now be described. Combustible fuel is fed into the valve 260. The air pump 216 draws air into the filter 264, through the fifth pipe 266, through the air pump 216, through the sixth pipe 218, into the separation chamber 268 formed between the inner wall 252 and the outer wall 254 and then into the valve 260. The valve 260 then injects a mixture of combustible fuel and air into the combustion chamber 256 at pre-determine time intervals. After the valve 260 injects a mixture of the combustible fuel and air into the combustion chamber 256 at pre-determine time intervals, the spark plug ignites the fuel / air mixture inside of the combustion chamber 256 to generate a series of combustions, which in turn produce a series of pulses of hot exhaust gas. The pulses of hot exhaust gases created by the combustions pass from the combustion chamber 256 through the third pipe 258 into the mixing chamber 212. The entry of the series of pulses of hot exhaust gas into the mixing chamber 212 generate a gas stream of pulsed hot exhaust gas inside of the mixing chamber 212. The tank is filled with fluid containing the solids. The fluid containing the solids then flows into the pump 206. The pump 206 then pumps the fluid with the solids through the second pipe 208 and the nozzle 214 and into the mixing chamber 212. As the fluid with the solids passes through the nozzle 214, it is atomized into a spray 238. The spray 238 mixes with the gas stream of pulsed hot exhaust gas where it is rapidly heated, the fluid vaporising as it does so, the pulsation of the gas stream assisting the atomisation. The vaporised fluid and solids then pass out of the mixing chamber 212 through the seventh pipe 226 and into the separating chamber 230 where it is rotated rapidly to cyclonically separate the solids from the vaporised fluid. The solids then exit the separation chamber 230 through the eight solids exit pipe 232. The vaporised fluid the exits the separation chamber 230 through the ninth vapour exit pipe 234 where the vaporised fluid is condensed in the condensing chamber 272 to return it to a liquid which can then exit the condensing chamber 272 via the tenth liquid exits pipe 276. The exhaust gas can then be removed from the condensing chamber 272 via the exit fan 280 and exhaust duct 284. A pulse combustion spray dryer has been used for extracting salts from a fluid, and as such, can be used to desalinate sea water. The paper entitled "Application of Pulse Combustion Technology in Spray Drying Process" by I Zbicinski, I Smucerowicz, C Strumillo and C Crowe of Technical University of Lodz, Faculty of Process and Environmental Engineering or Washington State University, School of Mechanical and Material Engineering, describes the use of such apparatus. A problem with pulse combustion spray drying apparatus as described in the second piece of prior art is that it requires the provision of a combustion fuel in order to operate. Another problem is that the fluid with the solid, once atomised are mixed with the exhaust gases of the burnt combustion fuel which may not be desirable. The third piece of prior art is a four-stroke diesel engine will now be described in relation to Figures 3A to 3D of WO23161599 and GB2619110. Referring to Figures 3A to 3D of WO23161599 and GB2619110, a diesel engine comprises a cylinder block 300 (using the reference numbers of WO23161599 and GB2619110) which is mounted on a crank shaft housing 302. The cylinder block 300 comprises an elongate cylinder 304 having a longitudinal axis and a uniform circular cross section, in a direction perpendicular to the axis, along the length of the cylinder 304. Slideably mounted within the cylinder 304 is a piston 306 of circular cross section of similar size to that of the cylinder 304. Mounted around the external sidewall of the piston 306 are piston rings (not shown) which form a seal between the external sidewall of the piston 306 and the internal side wall of the cylinder 304. The lower section of the cylinder 304 opens into a chamber 308 formed inside of the crank shaft housing 302. A rotatable crank shaft 310 is mounted inside of the crank housing 302 which is capable of rotating about an axis which extends perpendicularly to the longitudinal axis of the cylinder 304. A connecting rod 312 is pivotally attached to the crank shaft 310 at a lower end, the axis of pivot being parallel to but eccentrically off set from the axis of rotation of the crank shaft 310. The other upper end of the connecting rod 312 is pivotally attached to the piston 306, the axis of pivot being parallel to the axis of rotation of the crank shaft 310. Rotation of the crank shaft 310 results in a linear reciprocation motion of the piston 306 inside the cylinder 304 along the longitudinal axis of the cylinder 304 in well know manner. A counterweight 314 is eccentrically mounted on the crank shaft 310 to counteract any vibrations generated by the eccentric connection of the lower end of the connecting rod 312 as the crank shaft 310 rotates. The upper section of the cylinder 304 is terminated by an upper wall formed by the top of the cylinder block 300. A combustion chamber 318 is formed inside of the upper section of the cylinder which is bounded by the upper wall of the cylinder block 300 at the top, by the inner side wall of the cylinder 304 at the sides, and the top of the piston 306 at the bottom. As the piston 306 reciprocatingly slides up and down within the cylinder 304, the volume of the chamber 318 varies, the volume of the chamber 318 being the smallest when the piston 306 is in its highest position, closest to the upper wall of cylinder block 300; the volume of the chamber 318 being the largest when the piston 306 is in its lowest position, closest to the crank shaft 310. A first inlet passage 316 is formed through the upper wall which allows filtered air from outside of the cylinder block 300 to enter into the combustion chamber 318. A first slideable valve 320 is able to open and close the inlet passage 316. Movement of the valve 320 is controlled using a first cam shaft (not shown) in well-known manner. A second outlet passage 326 is formed through the upper wall which allows fumes from the burnt diesel to exit from the combustion chamber 318 to outside of the cylinder block 300. A second slideable valve 322 is able to open and close the outlet passage 326. Movement of the valve 322 is controlled using a second cam shaft (not shown) in well-known manner. An injector nozzle 324 in mounted in the upper wall between the inlet and outlet passages 316,326 through which diesel fuel can be injected in the combustion chamber 318 in well-known manner. Figures 3A to 3D of WO23161599 and GB2619110 show the combustion cycle of the engine. Figures 3A of WO23161599 and GB2619110 show the start of the cycle. At the start, the first valve 320 opens the first inlet passage 316. The second valve 322 closes the second outlet passage 326. At the star of the cycle, the piston 306 slides downwardly (Arrow A) in the cylinder 304 due to the rotation of the crank shaft 310, increasing the volume of the combustion chamber 318. As the volume of the combustion chamber 318 increases, air is drawn into the combustion chamber 318 through the first inlet passage 316. Figures 3B of WO23161599 and GB2619110 show the second stage of the combustion cycle. During the second stage, the first valve 320 closes the first inlet passage 316. The second valve 322 maintains the second outlet passage 326 closed. In the second stage, the piston 306 slides upwardly (Arrow B) in the cylinder 304 due to the continued rotation of the crank shaft 310, decreasing the volume of the combustion chamber 318. As the volume of the combustion chamber 318 decreases, the air in the combustion chamber 318 is compressed as both the first inlet passage 316 and second outlet passage 326 are closed. As the air is compressed, its pressure and temperature in the combustion chamber 318 increases. Figures 3C of WO23161599 and GB2619110 show the third stage of the combustion cycle. During the third stage, the first valve 320 maintains the first inlet passage 316 closed. The second valve 322 also maintains the second outlet passage 326 closed. In the third stage, the piston 306 moves to its upper most position (referred to as "top dead centre") in the cylinder 304. The volume of the combustion chamber 318 is the smallest when the piston 306 is in this position. The temperature and pressure of the air in the combustion chamber 318 are also at their highest. When the piston 306 is at top dead centre, diesel fuel is injected into the combustion chamber 318 through the nozzle 324. As the diesel fuel enters the combustion chamber 318, it begins to burn due to the elevated temperature of the air in the combustion chamber 318. The ignition of the fuel is caused by the elevated temperature of the air in the combustion chamber 318 due to the mechanical compression of the air (the diesel engine is a so-called "compression-ignition engine"). The burning of the diesel fuel causes the piston 306 to start moving downwardly (Arrow C), causing the crank shaft 310 to continue to rotate. Figures 3D of WO23161599 and GB2619110 show the end of the cycle. During the fourth stage, the first valve 320 maintains the first inlet passage 316 closed. The second outlet valve 322 opens the second outlet passage 326. During the fourth stage, the piston 306 slides upwardly (Arrow D) in the cylinder 304 due to the rotation of the crank shaft 310, decreasing the volume of the combustion chamber 318. As the volume of the combustion chamber 318 decreases, the fumes generated by the burning of the diesel fuel in the air in the combustion chamber 318 is expelled from the combustion chamber 318 through the second outlet passage 326. Most diesel engines work by compressing only the air (not a mixture of air and diesel fuel). A typical compression ratio of a diesel engine is between 14 to 1 and 22 to 1. This increases the air temperature inside the combustion chamber 318 to such a high degree that when atomised diesel fuel is injected into the combustion chamber 318, it ignites spontaneously. The temperature inside of the combustion chamber 318 when the air is fully compressed is typically greater than 526 degrees Centigrade (> 979 degrees Fahrenheit). It will be appreciated that there are also two stroke diesel engines. These also ignite atomised diesel fuel by first compressing the air inside of a combustion chamber to increase the temperature of the compressed air and then secondly injecting the diesel fuel into the combustion chamber to be ignited by the high temperature of the compressed air. The fourth piece of prior art is mechanical compressor which can be used with either a mechanical compression pulse spray dryer or a separator as described with reference to Figures 4A to 4D in WO23161599 and GB2619110 respectively. The fourth piece of prior art will now be described with reference to Figures 4A to 4D of GB2619110. The fourth piece of prior art discloses a separator which has a mechanical compressor in the form of a piston compressor. Referring to Figures 4A to 4D of GB2619110, the separation device comprises a piston compressor 484 (using the reference numbers of WO23161599 and GB2619110) which produces a series of pulses of compressed hot air, together with vapourised fluid and solids, and a separator 490. The piston compressor 484 comprises a cylinder block 400 which is mounted below a crank shaft housing (not shown). The cylinder block 400 comprises an elongate cylinder 404 having a longitudinal axis and a uniform circular cross section, in a direction perpendicular to the axis, along the length of the cylinder 404. Slideably mounted within the cylinder 404 is a piston 406 of circular cross section of similar size to that of the cylinder 404. Mounted circumferentially around the internal wall of the cylinder 404 towards the top of the cylinder 404 are two seals 408 which form a seal between the external sidewall of the piston 406 and the inner side wall of the cylinder 404 and which prevent any gases from passing the seals 408. The seals 408 slide along the external sidewall of the piston 406 when the piston 406 reciprocates within the cylinder 404. The upper section of the cylinder 404 opens into a chamber 410 formed inside of the crank shaft housing. The lower section of cylinder 404 forms a compression chamber 428, the compression chamber 428 being defined by the lower internal walls of the cylinder 404 and a lower surface 417 of the piston 406. A rotatable crank shaft 412 is mounted inside of the crank shaft housing which is capable of rotating about an axis which extends perpendicularly to the longitudinal axis of the cylinder 404. A connecting rod 414 is pivotally attached to the crank shaft 412 at an upper end, the axis of pivot being parallel to but eccentrically off set from the axis of rotation of the crank shaft 412. The lower end of the connecting rod 414 is pivotally attached to a first valve 416 formed in the top of the piston 406, the axis of pivot being parallel to the axis of rotation of the crank shaft 412. Rotation of the crank shaft 412 results in a linear reciprocation motion of the piston 406 inside the cylinder 404 along the longitudinal axis of the cylinder 404 in well known manner. A counterweight (not shown) is eccentrically mounted on the crank shaft 412 to counteract any vibrations generated by the eccentric connection of the upper end of the connecting rod 414 as the crank shaft 412 rotates. The first valve 416 comprises a valve chamber 418 formed in the top of the piston 406. The valve chamber 418 is circular in cross-section (perpendicularly to the longitudinal axis of the cylinder 404) with a flat lower side wall 420 and a flat upper side wall 422. A lower elongate tubular passage 424 extends from the lower side wall of the valve chamber 418 through the piston 406 to the lower surface 417 of the piston 406. The lower elongate tubular passage 424 allows air to freely pass between the valve chamber 418 and the compression chamber 428 of the cylinder 404. A first upper elongate tubular passage 434 extends from the upper side wall 422 of the valve chamber 418 through the piston 406 to the upper surface of the piston 406. The first upper elongate passage 434 extends parallel to and is co-axial with the longitudinal axis of the cylinder 404. A second upper elongate tubular passage 436 extends from the upper side wall 422 of the valve chamber 418 through the piston 406 to the upper surface of the piston 406. The second upper elongate passage 436 extends parallel to and but is offset from the longitudinal axis of the cylinder 404. The second upper elongate tubular passage 436 allows air to freely pass between the valve chamber 418 and the space 410 above the piston 406 facing towards and / or connected to the chamber in the crank shaft housing. Mounted inside of the valve chamber 418 are two valve disks 430,432. The top disk 430 is mounted on top of the lower disk 432, the two disks 430 432 being integrally formed as one component. The valve disks 430,432, are circular in cross-section (perpendicularly to the longitudinal axis of the cylinder 404), both having the same constant thickness (parallel to the longitudinal axis of the cylinder 404), both being smaller in diameter that the valve chamber 418, the top disk 430 being smaller in diameter than the lower disk 432. The top disk 430 is rigidly attached to the lower end of a slide rod 438. The slide rod 438 is sldieably mounted inside of a side bearing 440 mounted within the first upper tubular passage 434. The slide rod 438 extends parallel to and is co-axial with the longitudinal axis of the cylinder 404 and is capable of sliding axially along its longitudinal axis within the slide bearing 440. The upper end of the slide rod 438 is pivotally attached to the lower end of the connecting rod 414, the axis of pivot being parallel to the axis of rotation of the crank shaft 412. Rotation of the crank shaft 412 results in a linear reciprocation motion of the slide rod 438 inside of the slide bearing 440. A weak helical spring 442 is sandwiched between the upper side wall 422 of the valve chamber 418 and top surface of the disk 432, the lower end of the spring 442 surrounding the top disk 430. The spring 442 biases the two valves disks 430,432 towards their lowest position in the valve chamber 418. A seal 444 is mounted on the lower surface of the lower disk 432. When the two valve disks 430,432 are in their lowest position (as shown in Figures 4B and 4C), the seal 444 is sandwiched between the lower surface of the lower disk 432 and the lower flat side wall 420 of the valve chamber 418. When the seal 444 and valve disks 430,432 are in this position, the entrance to the lower elongate tubular passage 424 is sealed, thus preventing air from passing between the valve chamber 418 and the compression chamber 428 of the cylinder 404. When the two valve disks 430,432 are in their highest position (as shown in Figures 4A and 4D), the seal 444 is located away from the lower flat side wall 420 of the valve chamber 418. When the seal 444 and valve disks 430,432 are in this position, the entrance to the lower elongate tubular passage 424 is open, thus allowing air to pass freely between the valve chamber 418 and the compression chamber 428 of the cylinder 404. When the crank shaft 412 rotates to move the piston 406 downwardly inside of the cylinder 404, the crank shaft 412, causes the slide rod 438 to slide downwardly inside the slide bearing 440, moving the two valve disks 430,432 downwardly inside of the valve chamber 418 until the two valve disks 430,432 are in their lowest position (as shown in Figures 4B and 4C) with the seal 444 sandwiched between the lower surface of the lower disk 432 and the lower flat side wall 420 of the valve chamber 418. As the crank shaft 412 continues to rotate to move the piston 406 downwardly inside of the cylinder 404, the crank shaft 412, continues to push the slide rod 438 downwardly, the slide rod 438 pushing the valve disks 430,432 downwardly, which in turn push the piston 406 downwardly inside of the cylinder 404 by their engagement of the lower wall 420 of the valve chamber 418 . As the valve 430,432 pushes the piston 406 downwardly, the entrance to the lower elongate tubular passage 424 is sealed, thus preventing air from passing between the valve chamber 418 and the compression chamber 428 of the cylinder 404 as the piston 406 moves downwardly within the cylinder 404. When the crank shaft 412 rotates to move the piston 406 upwardly inside of the cylinder 404, the crank shaft 412 causes the slide rod 438 to slide upwardly inside the slide bearing 440, moving the two valve disks 430,432 upwardly inside of the valve chamber 418 until the two valve disks 430, 432 are in their highest position (as shown in Figures 4A and 4D) with the seal 444 located remotely from flat lower wall 420 of the valve chamber 418 and the upper disk 430 located against the upper flat side wall 422 of the valve chamber 418. As the crank shaft 412 continues to rotate to move the piston 406 upwardly inside of the cylinder 404, the crank shaft 412, continues to pull the slide rod 438 upwardly, the slide rod 438 pulling the valve disks 430,432 upwardly, which in turn pull the piston 406 upwardly inside of the cylinder 404 by their engagement of the flat upper side wall 422 of the valve chamber 418 . As the valve 430,432 pulls the piston 406 upwardly, the entrance to the lower elongate tubular passage 424 is open, thus allowing air to pass between the valve chamber 418 and the compression chamber 428 of the cylinder 404 as the piston 406 moves upwardly within the cylinder 404. The design of the first valve 416 is such that it acts a timing device for the entry of air into the compression chamber 428. When the piston 406 is moving upwardly, the first valve 416 opens, allowing air to enter into the compression chamber 428. When the piston 406 is moving downwardly, the first valve 416 closes, preventing air entering or exiting the compression chamber 428. A such, the first valve 416 controls when and when not air can pass through the first valve 416 dependent on the direction of movement of the piston 406 by the crank shaft 412. The lower section of the cylinder 404 is terminated by a lower wall formed by the bottom of the cylinder block 400. The compression chamber 428 is formed inside of the lower section of the cylinder 404 which is bounded by the lower wall of the cylinder block 400 at the bottom, by the side wall of the cylinder 404 at the sides, and the lower surface 417 of the piston 406 at the top. As the piston 406 reciprocatingly slides up and down within the cylinder 404, the volume of the compression chamber 428 varies, the volume of the compression chamber 428 being the smallest when the piston 406 is in its lowest position as shown in Figure 4C, closest to the lower inner wall of cylinder block 400, the volume of the chamber 428 being the largest when the piston 406 is in its highest position, closest to the crank shaft 412, as shown in Figure 4A. An inlet 1300 is formed through the side wall of the cylinder 404. The inlet 1300 is located approximately half-way along the length of cylinder 404 such that, when the volume of the compression chamber 428 is at its maximum, the inlet 1300 faces into the compression chamber 428 below the piston 406 as shown in Figure 4A. A tank (not shown), in which is inserted a fluid 1304 with dissolved solids, is connected via a pipe 1302 to the inlet 1300. A nozzle (not shown) can be optionally attached to the end of the pipe 1302. A valve 1308 is mounted in the pipe 1302 to ensure that the fluid 1304 with the dissolved solids can only flow one way into the compression chamber 428 and that pressurised air from the compression chamber 428 cannot exit the compression chamber 428 via the inlet 1300. The valve 1308 is opened and closed so that the fluid 1304 with dissolved solids can only flow through the valve 1308 into the compression chamber 428 at set times. The valve 1308 is mechanical linked (indicated by dashed lines 1306), for example by a cam mechanism or an eccentric drive, to the crank shaft 412 in order to enable the mechanical motion of the crank shaft 412 to utilised in opening and closing the valve 1308. When the crank shaft 412 is at pre-set angular positions, it opens the valve 1308 using the mechanical link 1306. When the crank shaft 412 is at the other angular positions, it closes the valve 1308 using the mechanical link 1306. As such, it can be ensured that the fluid 1304 with the dissolved solids only enters the compression chamber 428 when the piston 406 is at predetermined positions within the cylinder 404. The inlet 1300 acts as a mixer, mixing the fluid 1304 with dissolved solids with the gas inside of the compression chamber 428. The fluid 1304 containing the dissolved solids can flow into the compression chamber 428 due to gravity. However, it will be appreciated that a pump (not shown) can be used to assist with the flow of the fluid 1304 with the dissolved solids into the compression chamber 428, the pump pumping the fluid 1304 with the dissolved solids into the compression chamber 428 under a higher pressure than that generated by gravity. Such a pump can be activated when the valve 1308 is open and deactivated when the valve 1308 is closed. An outlet 446 is formed through the wall of the cylinder 404. The outlet 446 is located between the two seals 408. Formed in the side of the piston 406 is a U-shaped passage 448. The U shaped passage 448 and the two seals 408 form a second valve 486. The U shaped passage 448 connects between a lower entrance 450 formed in the side wall of the piston 406 and an upper entrance 452 formed inside wall of the piston 406 and which is located axially above the lower entrance 450. When the piston 406 reciprocatingly slides up and down, the U-shaped passage 448 similarly slides up and down with it. When the piston 406 is at its lowest position as shown in Figure 4C, the lower entrance 450 of the U shaped passage 448 is located below the lower of the two seals 408 whilst the upper entrance 452 of the U shaped passage 448 faces into the space formed between the two seals 408 towards the outlet 446. When the piston 406 is in this position, the air in the compression chamber 428, which is compressed and heated due to the compression chamber 428 having its smallest volume, is able to pass between the side of the piston 406, enter the lower entrance 450 of the U shaped passage 448, pass through the U shaped passage 448 and exit the upper entrance 452 of the U shaped passage 448, enter the space between the two seals 408 and then enter the outlet 446. The U shaped passage 448 enables the compressed heated air to by-pass the lower of the two seals 408, thus allowing the compressed heated air from the compression chamber 428 to exit via the outlet 446 when the piston 406 is located in this position. When the piston starts to move upwardly from its lowest position shown in Figure 4C, for a brief period of time, the upper entrance 452 of the U shaped passage 448 is located above the upper of the two seals 408 whilst the lower entrance 450 of the U shaped passage 448 faces into the space formed between the two seals 408 towards the outlet 446. During the brief period when the piston 406 is in this position, air located above the piston 406 is able to pass between the side of the piston 406 and the cylinder wall, enter the upper entrance 452 of the U shaped passage 448, pass through the U shaped passage 448, exit the lower entrance 450 of the U shaped passage 448, enter the space between the two seals 408 and then enter the outlet 446. Similarly, when the piston 406 is moving downwardly and is approaching its lowest position as shown in Figure 4C, for a brief period of time, the upper entrance 452 of the U shaped passage 448 is located above the upper of the two seals 408 whilst the lower entrance 450 of the U shaped passage 448 faces into the space formed between the two seals 408 towards the outlet 446. During the brief period when the piston 406 is in this position, air located above the piston 406 is able to pass between the side of the piston 406 and the cylinder wall, enter the upper entrance 452 of the U shaped passage 448, pass through the U shaped passage 448, exit the lower entrance 450 of the U shaped passage 448, enter the space between the two seals 408 and then enter the outlet 446. During the rest of the cycle of the reciprocation of the piston 406, both of the entrances 450, 452 are located above both seals 408. As such, the space between the seals 408 is sealed by the side of the piston 406, sealing the entrance to outlet 446. As such, air is unable to pass through the outlet 446. The design of the second valve 486 is such that it acts a timing device for the exit of air from the compression chamber 428. When the piston 406 has moved to its lowest position, the second valve 486 opens, allowing air to exit the compression chamber 428. When the piston 406 subsequently moves upwardly, the second valve 486 closes, preventing air entering or exiting the compression chamber 428 through the second valve 486. As such, the second valve 486 controls when and when not air can pass through the second valve 486 dependent on the position of the piston 406 within the cylinder 404. The separator 490 comprises a housing 458 which forms a cyclonic separator 468. The cyclonic separator 468 forms a separation chamber 470 which tapers at its lower end to a solids exit pipe 472. The outlet 446 connects to the top of the housing 458 via a connection pipe 466 so that any air exiting the compression chamber 428 via the outlet 446 can pass through the connection pipe 466 and into the cyclonic separator 468. A vapour exit pipe 474 connects to an aperture formed through an upper part of the wall of the cyclonic separator 468 to a vapour pump 476. The vapour exit pipe 474 is made of material, such as metal, which conducts heat efficiently. Attached, in a heat conductive manner, to the side of the vapour exit pipe 474, are a series of fins 478, each of which are made from heat conductive material such as metal. The vapour exit pipe 474, together with the fins 478, act as a condenser, cooling any gases, liquids and / or and vapours which pass through the vapour exit pipe 474 from the cyclonic separator 468 to a vapour pump 476. An exit pipe 480 connects to the vapour pump 476 and extends downwardly towards a collection tank 482. The operation of the separation device will now be described with reference to Figures 4Ato 4D of GB2619110. During the operation of the separation device, the piston compressor 484 produces a series of pulses of compressed hot air containing vapourised fluid 1304 and entrained solids released from the fluid 1304 when it was vapourised. These are fed into the separator 490 where the solids are separated from the hot air and vapourised fluid 1304. The solids are then discharged from the separator 490. The vaporized fluid is then condensed, discharged from the separator 490 and then collected. Figures 4A to 4D ofGB2619110 show the operating cycle of the separation device, Figures 4A to 4D showing the piston compressor 484 in four different operating positions during the cycle. In order for the piston compressor 484 to operate to produce a series of pulses of compressed hot air, the crank shaft 412 of the pulse compressor must be rotationally driven (Arrow M) by an external rotary force. The crank shaft 412 is rotationally driven in the direction of Arrow M in order drive the piston compressor 484 through its cycle. The crank shaft 412 is rotated using the external force. Figure 4A of GB2619110 shows the start of the cycle. At the start, the crank shaft 412 has moved the piston 406, using the connecting rod 414, to its highest position within the cylinder 404. The connecting rod 414 is attached to the slide rod 438 of the first valve 416. Because the crank shaft 412 has moved the piston 406 to its highest position, the slide rod 438 has been slid upwardly inside the slide bearing 440, moving the two valve disks 430,432 upwardly inside of the valve chamber 418 until the two valve disks 430,432 are in their highest position (as shown in Figures 4A) with the seal 444 located remotely from lower wall 420 of the valve chamber 418 and the upper disk 430 located against the upper wall of the valve chamber 418. As such, the entrance to the lower elongate tubular passage 424 is open, thus allowing air to pass between the valve chamber 418 and the compression chamber 428 of the cylinder 404. The compression chamber 428 is at its greatest volume VI when the piston 406 is in its highest position. As the valve disks 430, 432 are in their highest position, air is able pass from above the piston 406 from the surrounding atmosphere, through the second upper elongate passage 436, through the valve chamber 418 and then through the lower elongate tubular passage 424 and into the compression chamber 428 of the cylinder 404. As such, the air pressure inside the compression chamber 428 is the same as that of the atmosphere surrounding the piston compressor. When the piston 406 is in its highest position, the volume of the compression chamber 428 is at its maximum VI and the inlet 1300 faces into the compression chamber 428 below the piston 406 as shown in Figure 4A. Whilst the piston 406 is in its highest position, as shown in Figure 4A, the valve 1308 is opened by the crank shaft 412 via the mechanical link 1306. The fluid 1304 containing the dissolved solids flows from the tank (not shown) via the pipe 1302 to the inlet 1300 and then into the compression chamber 428. The fluid 1304 with dissolved solids mixes with the air in the compression chamber 428. As such, the inlet acts as a mixer. The valve 1308 is kept open for a predetermine amount of time by the crank shaft 412 as it passes through a predetermined range of angular positions whilst the piston 406 is approaches, passes through and leaves its highest position, to ensure that a predetermine amount of fluid 1304 with dissolved solids enters the compression chamber 428. Once the crank shaft 412 exits the predetermined range of angular positions, it closes the valve 1304. When the piston 406 is in its highest position, as shown in Figure 4A of GB2619110, both of the entrances 450,452 of the U shaped passage 448 of the second valve 486, are located above both seals 408. As such, the space between the seals 408 is sealed by the side of the piston 406 and therefore the entrance to outlet 446 is sealed by the second valve 486 and as such, air is unable to pass through the outlet 446. Figure 4B of GB2619110 shows the second stage of the cycle. During the second stage, the crank shaft 412 is moving the piston 406 downwardly (Arrow N), using the connecting rod 414 which is attached to the first valve 416. As the crank shaft 412 rotates (Arrow M) to move the piston 406 downwardly inside of the cylinder 404, the crank shaft 412 causes the slide rod 438 to slide downwardly inside the slide bearing 440, moving the two valve disks 430,432 downwardly inside of the valve chamber 418 until the two valve disks 430,432 are in their lowest position (as shown in Figure 48 of GB2619110) with the seal 444 sandwiched between the lower surface of the lower disk 432 and the flat side wall 420 of the valve chamber 418. As the crank shaft 412 continues to rotate (Arrow M) to move the piston 406 downwardly inside of the cylinder 404, the crank shaft 412 continues to push the slide rod 438 downwardly, the slide rod 438 pushing the valve disks 430,432 downwardly, which in turn push the piston 406 downwardly inside of the cylinder 404 by their engagement of the lower wall 420 of the valve chamber 418 . As the valve 430,432 pushes the piston 406 downwardly (Arrow N), the entrance to the lower elongate tubular passage 424 is sealed, thus preventing air from passing between the valve chamber 418 and the compression chamber 428 of the cylinder 404 as the piston 406 moves downwardly within the cylinder 404. As such, air is unable to pass from above the piston 406 from the surrounding atmosphere into the compression chamber 428 of the cylinder 404. When the piston 406 is being moved downwardly, the volume of the compression chamber 428 is reduced. The inlet 1300 faces into the side of the piston 406 inside of compression chamber 428 as shown in Figure 48. When the piston 406 is in this position, the valve 1308 is kept closed by the crank shaft 412 via the mechanical link 1306. As such, additional fluid 1304 containing the dissolved solids is prevented from entering the compression chamber 428. Furthermore, the closed valve 1308 prevents any air, fluid or solids inside the compression chamber 428 exiting the compression chamber 428, as the pressure increases, through the inlet 1300. When the piston is being moved downwardly (Arrow N) by the crank shaft 412 as shown in Figure 48, both of the entrances 450,452 of the U shaped passage 448 of the second valve 486, remain located above both seals 408. As such, the space between the seals 408 is sealed by the side of the piston 406 and therefore the entrance to outlet 446 is sealed by the second valve 486 and as such, air is unable to pass through the outlet 446. As such, the compression chamber 428 in the cylinder 404 is completely sealed, with air being unable exit through either the first or second valves 416,486. Therefore, as the piston 406 moves downwardly, the air located in the compression chamber 428 becomes compressed, with both the pressure and temperature of the air within the compression chamber 428 increasing. As the air pressure in the compression chamber increases, an upward force is exerted onto the piston 406, which in turn assists in maintaining the engagement of the disks 430,432 and seal 444 with the lower wall 420 of the valve chamber 418. Furthermore, as the temperature of the air the compression chamber 428 increases, the temperature of the fluid 1304 with the dissolved solids also increases. This results in the fluid 1304 evaporating, the solids dissolved within the fluid 1304 being released from the fluid 1304 and being able to move around the compression chamber 428 inside the heated air and vapourised fluid. Figure 4C of GB2619110 shows the third stage of the cycle. During the third stage, the crank shaft 412 has moved the piston 406 to its lowest position within the cylinder 404. In this position, the compression chamber 428 has its smallest volume V2. As such, the air located in the compression chamber 428 is at its maximum compression with both the pressure and temperature of the air, vapourised fluid 1304 and solids in the compression chamber 428 being at their maximum. As the air pressure in the compression chamber is much higher than that exerted on the top of the piston 406 (which is that of the surrounding atmosphere), an upward force is exerted onto the piston 406. As such, the two valve disks 430, 432 are maintained in their lowest position in the valve chamber 418 (as shown in Figure 4C) with the seal 444 is sandwiched between the lower surface of the lower disk 432 and the flat side wall 420 of the valve chamber 418. Therefore, the entrance to the lower elongate tubular passage 424 remains sealed, thus preventing air from passing between the valve chamber 418 and the compression chamber 428 of the cylinder 404. When the piston 406 is at its lowest position, the volume of the compression chamber 428 is at its minimum. The inlet 1300 faces into the side of the piston 406 inside of compression chamber 428 as shown in Figure 4C. When the piston 406 is in this position, the valve 1308 is kept closed by the crank shaft 412 via the mechanical link 1306. As such, additional fluid 1304 with dissolved solids is prevented from entering the compression chamber 428. Furthermore, the closed valve 1308 prevents any air, fluid or solids inside the compression chamber 428, exiting the compression chamber 428 as the pressure increases, through the inlet 1300. As the piston 406 moves downwardly (Arrow N), towards the position shown in Figure 4C, for a brief period of time, the upper entrance 452 of the U shaped passage 448 is located above the upper of the two seals 408 whilst the lower entrance 450 of the U shaped passage 448 faces into the space formed between the two seals 408 towards the outlet 446. During the brief period when the piston 406 is in this position, air located above the piston 406 is able to pass between the side of the piston 406 near the top of the piston 406 and the cylinder wall, enter the upper entrance 452 of the U shaped passage 448, pass through the U shaped passage 448 and exit the lower entrance 450 of the U shaped passage 448, enter the space between the two seals 408 and then enter outlet 446. When the piston has moved to its lowest position as shown in Figure 4C, the lower entrance 450 of the U shaped passage 448 is located below the lower of the two seals 408 whilst the upper entrance 452 of the U shaped passage 448 faces into the space formed between the two seals 408 towards the outlet 446. When the piston 406 is in this position, the air, vapourised fluid 1304 and solids in the compression chamber 428, which is at its maximum compression and highest temperature due to the compression chamber having its smallest volume V2, is able to pass between the lower side of the piston 406, enter the lower entrance 450 of the U shaped passage 448, pass through the U shaped passage 448 and exit the entrance 452 of the U shaped passage 448, enter the space between the two seals 408 and then enter the outlet 446. As the air, vapourised fluid and solids in the compression chamber 428 is at the maximum pressure and temperature, a pulse of compressed and heated air, with the vapourised fluid and solids, enters the outlet 446. The pulse of compressed and heated air, with the vapourised fluid and solids, then passes through the second pipe 466 and into the housing 458 which forms the cyclonic separator 468. The heated air, vapourised fluid 1304 and solids then enter the cyclonic separation chamber 470 where the solids are separated from the heated air and vapourised fluid 1304. As the pulse of compressed and heated air, with the vapourised fluid and solids, passes between the side of the piston 406, enters the lower entrance 450 of the U shaped passage 448, passes through the U shaped passage 448 and exits the upper entrance 452 of the U shaped passage 448, enters the space between the two seals 408, enters the outlet 446, through the second pipe 466 and into the mixing chamber 460 of the housing 458, the pressure and temperature of the pulse of air will drop as the air expands and cools. As such, the combined volumes of the compression chamber at its smallest volume V2 (Figure 4C of GB2619110) and the volume V3 of the interconnection passageway between the compression chamber 428 and the mixing chamber 460 (comprising the volume of the space down the lower side of the piston 406, the volume of the space in the U shaped passage 448, the volume of space between the two seals 408 and the volume within the second pipe 466) needs to be less than the volume of the compression chamber 428 at its maximum volume VI, and ideally significantly less, in order to ensure that the pulse of air entering the mixing chamber 460 is at a reasonable pressure and temperature in order for it to vaporise any atomised fluid entering the mixing chamber 460. Figure 4D of GB2619110 shows the fourth stage of the cycle. During the fourth stage, the crank shaft 412 is moving the piston 406 upwardly, using the connecting rod 414 which is attached to the first valve 416. When the piston 406 is being moved upwardly, the volume of the compression chamber 428 is increasing. The inlet 1300 faces into the side of the piston 406 inside of compression chamber 428 as shown in Figure 4D. When the piston 406 is in this position, the valve 1308 Is kept closed by the crank shaft 412 via the mechanical link 1306. As such, the fluid 1304 containing the dissolved solids is prevented from entering the compression chamber 428. When the piston 404 starts to move upwardly (Arrow O) from its lowest position as shown in Figure 4C, fora brief period of time, the upper entrance 452 of the U shaped passage 448 is located above the upper of the two seals 408 whilst the lower entrance 450 of the U shaped passage 448 faces Into the space formed between the two seals 408 towards the outlet 446. During this brief period when the piston 406 is in this position, air located above the piston 406 is able to pass between the side of the piston 406 near the top of the piston 406 and the cylinder wall, enter the upper entrance 452 of the U shaped passage 448, pass through the U shaped passage 448, exit the lower entrance 450 of the U shaped passage 448, enter the space between the two seals 408 and then enter the outlet 446. Subsequently, as the piston is being moved upwardly (Arrow 0) by the crank shaft 412 as shown in Figure 4D, both of the entrances 450,452 of the U shaped passage 448 of the second valve 486, remain located above both seals 408. As such, the space between the seals 408 is sealed by the side of the piston 406 and therefore the entrance to outlet 446 is sealed by the second valve 486 and as such, air is unable to pass through the outlet 446. As the crank shaft 412 rotates to move the piston 406 upwardly inside of the cylinder 404, the crank shaft 412 causes the slide rod 438 to slide upwardly inside the slide bearing 440, moving the two valve disks 430,432 upwardly inside of the valve chamber 418 until the two valve disks 430,432 are in their highest position (as shown in Figure 4D) with the seal 444 located remotely from lower wall of the valve chamber 418 and the upper disk 430 located against the upper wall 422 of the valve chamber 418. As the crank shaft 412 continues to rotate (Arrow M) to move the piston 406 upwardly inside of the cylinder 404, the crank shaft 412, continues to pull the slide rod 438 upwardly, the slide rod 438 pulling the valve disks 430, 432 upwardly, which in turn pull the piston 406 upwardly inside of the cylinder 404 by their engagement of the upper wall 422 of the valve chamber 418 . As the valve 430,432 pulls the piston 406 upwardly, the entrance to the lower elongate tubular passage 424 is open, thus allowing air to pass between the valve chamber 418 and the compression chamber 428 of the cylinder 404 as the piston 406 moves upwardly within the cylinder 404. As such, as the piston 406 rises, air is able pass from above the piston 406 from the surrounding atmosphere, through the second upper elongate passage 436, through the valve chamber 418 and then through the lower elongate tubular passage 424 and into the compression chamber 428 of the cylinder 404. Therefore, air is able to enter the compression chamber 428 as the piston 406 moves upwardly, replenishing the air previously emitted as a pulse through the outlet 446. The air pressure inside the compression chamber 428 remains the same as that of the surrounding atmosphere as it is replenished as the piston 406 moves upwardly. This allows the compression chamber 428 to be fully replenished with air when it reaches its highest position as shown in Figure 4A of GB2619110. Once the piston 406 has returned to the position shown in Figure 4A of GB2619110, the cycle of the piston compressor 484 is repeated as the crank shaft 412 continues to rotate (Arrow M). Each 360 degree rotation of the crank shaft 412 results in a single cycle of the piston compressor 484. Each cycle results in a single pulse of compressed heated air, with vapourised fluid 1304 and solids, entering the cyclonic separation chamber 470 of the housing 458 of the separator. The operation of the separator 490 in conjunction with the piston compressor 484 will now be described. The pulse of heated air, vapourised fluid 1304 and the solids enter the cyclonic separation chamber 470 of the housing 458 of the separator. The solids are separated from the heated air and vapourised fluid 1304, the solids exiting the cyclonic separation chamber 470 via the solids exit pipe 472. The vapourised fluid 456 then passes through the vapour exit pipe 474 to the vapour pump 476. As the vapourised fluid 456 passes through the vapour exit pipe 474, the heat of the vapourised fluid 456 transfers to the fins 478 via the pipe 474 where it is dissipated into the surrounding environment. As such, the vapourised fluid 456 is condensed as it passes through the fourth vapour exit pipe 474 and turns back into a liquid by the time it arrives at the vapour pump 476. The liquidised fluid 456 then passes through the exit pipe 480 towards the collection tank 482 where the fluid is collected. It should be noted that WO23161599 describes with reference to Figures 4A to 4D the same mechanical compressor as that described with reference to Figures 4Ato 4D of GB2619110. The mechanical compressor described with reference to Figures 4Ato 4D in WO23161599 is also in the form of a piston compressor. The fifth piece of prior art is a Wankel engine. The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion. The Wankel engine's rotor, which creates the turning motion, is similar in shape to a Reuleaux triangle, with the sides having less curvature. The rotor spins inside a figure-eightlike epitrochoidal housing ("shaped housing"), around a fixed-toothed gearing. The midpoint of the rotor moves in a circle around the output shaft, spinning the shaft via a cam. There are two types of Wankel engine of which the Kreiskolbenmotor ("KKM") type wankel engine, designed by Hanns-Dieter Paschke, forms the most relevant piece of prior art. In a KKM engine, the outer housing is stationary. The inner shaft is a moving part and has an eccentric lobe which acts as a cam for the inner rotor to spin around. The rotor spins around its center, and around the axis of the shaft in a hula hoop fashion, resulting in the rotor making one complete revolution for every three revolutions of the shaft. In the KKM engine, torque is taken off the shaft. The design and operation of a Wankel engine is well known and therefore will not be described further. US2988065 discloses a KKM Wankel engine. According to a first embodiment of the present invention, there is provided a compression mechanism for a mechanical compression pulse spray dryer or a separation device comprising: a cylinder block which forms a cylinder; a piston slideably mounted within the cylinder such that the piston and cylinder can move relative to each other; a compression chamber formed between the piston and cylinder, the volume of which alters depending on the position of the piston within the cylinder; at least one valve which allows a gas to enter and / or exit the compression chamber; wherein the cylinder block and the piston form the at least one valve. It will be appreciated that the gas can be air from the surrounding atmosphere or a gas from a gas cylinder or another source The position of the piston within the cylinder preferably determines whether the at least one valve is open or closed. The relative movement of piston inside of the cylinder can also act as a timing device, its movement opening and closing the at least one valve as the piston slides within the cylinder. Ideally, the pressure of the gas when it enters the compression chamber is substantially less than when it exits the compression chamber and the temperature of the gas when it enters the compression chamber is substantially less than when it exits the compression chamber. Preferably, the at least one valve allows the gas to exit the compression chamber when the gas has been compressed and the pressure and temperature of the gas has been increased, and preferably, in the form of a pulse. Preferably, the compression mechanism comprises: • a first set of passageways are formed in the piston; • a second set of passageways formed in the cylinder block; wherein the piston can move between: at least one first position within the cylinder where at least part of the first set of passageways of the piston aligns with at least part of the second set of passageways of the cylinder block to form a first conduit between the compression chamber and a gas supply; and at least one second position within the cylinder where at least part of the first set of passageways of the piston aligns with at least part of the second set of passageways of the cylinder block to form a second conduit between the compression chamber and an external device. It will be appreciated that the gas supply can be air from the surrounding atmosphere or gas from a gas cylinder or gas from another source. The external device can be a mechanical compression pulse spray dryer or a separation device second conduit, for example, such as the ones described in WO23161599 and GB2619110. It will be appreciated that the least part of the first set of passageways of the piston when the piston is in the at least one first position within the cylinder can either 1) be same as the same as the at least part of the first set of passageways of the piston when the piston is at least one second position within the cylinder or 2) be a different part of the at one least part of the first set of passageways of the piston when the piston is in the at least one second position within the cylinder or 3) be partly the same and partly different from the at one least part of the first set of passageways of the piston when the piston is in at least one second position within the cylinder. It will also be appreciated that the least part of the second set of passageways of the cylinder block when the piston is in the at least one first position within the cylinder can either 1) be same as the same as the at least part of the second set of passageways of the cylinder block when the piston is at least one second position of the within the cylinder or 2) be a different part of the at one least part of the second set of passageways of the cylinder block when the piston is in at least one second position the within the cylinder or 3) be partly the same and partly different from the at one least part of the second set of passageways of the cylinder block when the piston is in at least one second position of the within the cylinder. When the piston is located between its first position and its second position; the first set of passageways and second set passageways can be located relative to each other such that the compression chamber is sealed so that gas can neither enter or exit the compression chamber. The passageways can be in the form of either a groove or a channel within the piston or cylinder block. There can be a plurality of seals located between the sides of the piston and the walls of the cylinder which restrict the movement of a gas between the sides of the piston and the walls of the cylinder. The plurality of seals can: 1) aid in the formation of the first conduit when the piston is in Its at least one first position 0 in the cylinder; 2) aid in the formation of the second conduit when the piston is in its at least one second position in the cylinder; and 3) aid in the sealing of the compression chamber when the piston is located between its at least one first position and its at least one second position. According to a second aspect of the present invention, there is provided a compression mechanism for a mechanical compression pulse spray dryer or a separation device comprising: a shaped housing which forms a chamber; a rotor moveably mounted within the chamber such that the rotor can move in a rotational manner within the chamber; at least one air pocket formed between the rotor and shaped housing the volume of which alter depending on the position of the rotor within the shaped housing; at least one opening which allows a gas to enter and / or exit the at least one air pocket; wherein the relative position of the rotor within the shaped housing determines whether the at least one opening is open or closed. The relative movement of rotor inside of the shaped cylinder can act as a timing device, its movement opening and closing the at least one opening as the rotor moves in a rotational manner within the shaped housing. The pressure of the gas when it enters the at least one air pocket can be substantially less than when it exits the at least one air pocket and the temperature of the gas when it enters the at least one air pocket is substantially less than when it exits the at least one air pocket. The gas can exit the at least one air pocket when the gas has been compressed and the pressure and temperature of the gas has been increased, and preferably, in the form of a pulse. Three embodiments of the invention will now be described with reference to the following drawings of which: Figure 1A shows the first embodiment of the present invention comprising a mechanical compressor having a piston slidably mounted within a cylinder, the piston being located at its lowest position; Figure IB shows the first embodiment of the present invention shown in Figure 1A with the piston being located at its highest position; Figure 2A shows the second embodiment of the present invention comprising a mechanical compressor having a piston slidably mounted within a cylinder, the piston being located at its lowest position; Figure 2B shows the second embodiment of the present invention shown in Figure 2A with the piston being located at its highest position; Figure 3A shows the third embodiment of the present invention comprising a mechanical compressor having a rotor rotatably mounted within a shaped housing with the rotor in its first rotational position to allow air to enter one of the three compression chambers; Figure 3B shows the third embodiment of the present invention shown in Figure 3A with the rotor in its second rotational position where the air in the one compression chamber is compressed; Figure 3C shows the third embodiment of the present invention shown in Figure 3A with the rotor in its third rotational position where the compressed air in the one compression chamber is allowed to exit; and Figure 3D shows the third embodiment of the present invention shown in Figure 3A with the rotor in its fourth rotational position where the air in the one compression chamber is set to atmospheric pressure. 1st EMBODIMENT The first embodiment of the invention will now be described with reference to Figures 1A and IB. Figures 1A and IB show a mechanical compressor comprising a piston compressor 584 which produces a series of pulses of compressed hot air (sometimes can be referred to as a "gas"). The compressed hot air can also include vapourised fluid and / or solids. The piston compressor 584 comprises a cylinder block 500 which is mounted below a crank shaft housing (not shown). The cylinder block 500 comprises an elongate cylinder 504 having a longitudinal axis and a uniform circular cross section, in a direction perpendicular to the axis, along the length of the cylinder 504. Slideably mounted within the cylinder 504 is a piston 506 of circular cross section of similar size but slightly smaller to that of the cylinder 504. Mounted circumferentially around the external wall of the piston 506 are six seals 540 to 550 which each form a seal between the external sidewall of the piston 506 and the inner side wall of the cylinder 504 and which prevent any gases from passing the seals 540 - 550. The seals 540 -550 slide along the internal sidewall 552 of the cylinder 504 when the piston 506 reciprocates within the cylinder 504. The six seals 540 - 550 are each in the form of an O ring which surround the piston 506 and which are each located in a circumferential groove (not shown) formed around the piston 506 in well-known manner. The upper section of the cylinder 504 opens into a chamber (not shown) formed inside of the crank shaft housing (not shown). The lower section of cylinder 504 forms a compression chamber 510, the compression chamber 510 being defined by the internal walls at the end of the cylinder 504 and an end surface 517 of the piston 506. A rotatable crank shaft (not shown) is mounted inside of the crank shaft housing which is capable of rotating about an axis which extends perpendicularly to the longitudinal axis of the cylinder 504. A connecting rod 514 is pivotally attached to the crank shaft at one end, the axis of pivot being parallel to but eccentrically off set from the axis of rotation of the crank shaft. The other end of the connecting rod 514 is pivotally attached to the piston 506, the axis of pivot being parallel to the axis of rotation of the crank shaft. Rotation of the crank shaft results in a linear reciprocation motion of the piston 506 inside the cylinder 504 along the longitudinal axis of the cylinder 504 in well-known manner. A counterweight (not shown) is eccentrically mounted on the crank shaft to counteract any vibrations generated by the eccentric connection of the connecting rod 514 as the crank shaft rotates. The first O ring 540 is located adjacent the end of the piston 506 where the crank shaft pivotally attaches the piston 506. The sixth O ring 550 is located adjacent the end of the piston 506 which forms part of the wall of the compression chamber 510. The second to fifth O rings 542 -548 are located along the length of the piston 506 in consecutive positions between the first 540 and sixth 550 O rings. Formed inside of the piston 506 is a first passageway in the form of a U-shaped channel 520. One end of the U-shaped channel 520 opens to a first aperture 522 formed in the side wall of the piston 506. The other end of the U shaped channel 520 opens to a second aperture 524 formed in the side wall of the piston 506. Hie first and second apertures 522,524 are located on the side wall of the piston 506 at the same angular position around the longitudinal axis of the cylinder 504 but at longitudinally axially spaced positions from each other in a direction parallel to the longitudinal axis of the cylinder 504 as shown in Figures 1A and IB. The first aperture 522 is located immediately between the second 542 and third 544 O rings, the O rings being located in close proximity to the first aperture 522. The second aperture 524 is located between the fourth 546 and fifth 548 O rings, the O rings being located in close proximity to the second aperture 524. Formed inside of the cylinder block 500 is a second passageway in the form of a U-shaped channel 530. One end of the U shaped channel 530 opens to a third aperture 532 formed in the side wall of the cylinder 504. The other end of the U shaped channel 530 opens to a fourth aperture 534 formed in the side wall of the cylinder 504. The third and fourth apertures 532,534 are located on the side wall of the cylinder 504 at the same angular position around the longitudinal axis of the cylinder 504 but at longitudinally axially spaced positions from each other in a direction parallel to the longitudinal axis of the cylinder 504 as shown in Figures 1A and IB. The fourth aperture 534 faces towards and opens up to the compression chamber 510 regardless of the position of the piston 506 within the cylinder 504. The first and second apertures 522,524 of the first passageway and the third and fourth apertures 532,534 of the second passageway are located at the same angular position around the longitudinal axis of the cylinder 504. Formed inside of the cylinder block 500 is a third passageway in the form of a straight channel 560. One end of the channel 560 opens to a fifth aperture 562 formed in the side wall of the cylinder 504. The other end of the channel 560 connects to the surrounding atmosphere comprising air surrounding the mechanical compressor. Formed inside of the cylinder block is a fourth passageway in the form of a straight channel 570. One end of the channel 570 opens to a sixth aperture 572 formed in the side wall of the cylinder 504. The other end of the channel 570 is capable of connecting to an input of either a pulse sprayer or a separator (such as the ones described in of WO23161599 and GB2619110). The fifth and sixth apertures 562, 572ofthe third and fourth passageways are located on the side wall of the cylinder 504 at the same angular position around the longitudinal axis of the cylinder 504 as each other but at longitudinally axially spaced positions from each other in a direction parallel to the longitudinal axis of the cylinder 504. The fifth and sixth apertures 562, 572 of the third and fourth passageways also are located at the same angular position around the longitudinal axis of the cylinder 504 as the first and second apertures 522,524 of the first passageway and the third and fourth apertures 532,534 of the second passageway The third aperture 532 of the second passageway is located between the fifth and sixth apertures 562,572 of the third and fourth passageways. When the piston 506 is in its highest position as shown in in Figure IB, the fifth aperture 562 of the third passageway faces towards and opens to the first aperture 522 of the first passageway. As such, air can pass between the first and third passageways through the first and fifth apertures 522, 562. The second and third O rings 542,544 ensure that all the air passes between the first and fifth passageways 522, 562, preventing none of the air from passing between the side of the piston 506 and side wall of the cylinder 504. Furthermore, when the piston 506 is in its highest position as shown in in Figure IB, the third aperture 532 of the second passageway faces towards and opens to the second aperture 524 of the first passageway. As such, air can pass between the first and second passageways through the second and third apertures 524,532. The fourth and fifth O rings 546,548 ensure that all the air passes between the first and second passageways, preventing none from passing between the side of the piston 506 and side wall of the cylinder 504. The sixth 572 of the fourth passageway faces the side wall of the piston 506 between the fifth and sixth O rings 548, 550. As such, the sixth aperture 572 is sealed thus preventing any air from passing along the fourth passageway. Therefore, when the piston 506 is in its highest position as shown in in Figure IB, air can pass from the surrounding atmosphere, through the third passageway, through the first passageway and then through the second passageway and into the compression chamber 510. The movement of the piston 506 inside of the cylinder 504 acts as a valve to allow air into or out of the compression chamber 510, the relative movement opening and closing the valves. When the piston 506 is at its highest position, the valve is open allowing air into the compression chamber 510. When the piston 506 is in its lowest position as shown in in Figure 1A, the third aperture 532 of the second passageway faces towards and opens to the first aperture 522 of the first passageway. As such, air can pass between the first and second passageways through the first and third apertures 522,532. The second and third O rings 542,544 ensure that all the air passes between the first and second passageways, preventing none of the air from passing between the side of the piston 506 and side wall of the cylinder 504. Furthermore, when the piston 506 is in its lowest position as shown in in Figure 1A, the sixth aperture 572 of the fourth passageway faces towards and opens to the second aperture 524 of the first passageway. As such, air can pass between the first and fourth passageways through the second and sixth apertures 524,572. The fourth and fifth O rings 546,548 ensure that all the air passes between the first and fourth passageways, preventing none from passing between the side of the piston 506 and side wall of the cylinder 504. The fifth aperture 562 of the third passageway faces the side wall of the piston 506 between the first and second 0 rings 540,542. As such, the fifth aperture 562 is sealed thus preventing any air from passing along the third passageway. Therefore, when the piston 506 is in its lowest position as shown in in Figure 1A, air can pass from the compression chamber 510, through the second passageway, through the first passageway and then through the fourth passageway and then is capable of passing into either a mechanical compression pulse spray dryers such as one disclosed in WO23161599 or a separation devices disclosed in GB2619110 assuming the fourth passageway is connected to such a device. The movement of the piston 506 inside of the cylinder 504 acts as a valve to allow air into or out of the compression chamber 510, the relative movement opening and closing the valves. When the piston 506 is at its lowest position, the valve is open allowing compressed air out of the compression chamber 510 in the form of a pulse. When the piston 506 is moving between its highest position to its lowest position and vice versa; 1. The fifth aperture 562 of the third passageway faces the side wall of the piston 506 between the first and second O rings 540,542. As such, the fifth aperture 562 is sealed thus preventing any air from passing along the third passageway. 2. The first aperture 522 of the first passageway faces the side wall of the cylinder 504 between the second and third O rings 542, 544. As such, the first aperture 522 is sealed thus preventing any air from passing along the first passageway. 3. The third aperture 532 of the second passageway faces the side wall of the piston 506 between the third and fourth O rings 544,546. As such, the third aperture 532 is sealed thus preventing any air from passing along the second passageway. 4. The second aperture 524 of the first passageway faces the side wall of the cylinder 504 between the fourth and fifth O rings 546,548. As such, the second aperture 524 is sealed thus also preventing any air from passing along the first passageway. 5. The sixth aperture 572 of the fourth passageway faces the side wall of the piston 506 between the fifth and sixth O rings 548, 550. As such, the sixth aperture 572 is sealed thus preventing any air from passing along the fourth passageway. 6. The fourth aperture 534 of the second passageway faces the compression chamber 510. 7. The position of the piston 506 inside of the cylinder 504 is such the valves, to allow air into or out of the compression chamber 510, are closed. As such, the compression chamber 510 is sealed with air prevented from entering or exiting the compression chamber 510 when the piston 506 is moving between its highest position to its lowest position and vice versa. The operating cycle of the first embodiment of the mechanical compressor will now be described with reference to Figures 1A and IB. In order for the mechanical compressor to operate to produce a series of pulses of compressed hot air, the crank shaft must be rotationally driven by an external rotary force to move the piston 506 up and down within the cylinder 504. Such a force can be generated by a separate fan or propellor (not shown) due to the movement of air or water through the fan or propellor such as wind acting on a wind turbine or sea water passing through a water turbine due to the movement of the water caused by the tide. Alternatively, the force could be generated by an electric motor (not shown), a pneumatic motor (not shown), a hydraulic motor (not shown), a petrol or diesel engine (not shown) or any known device which is capable of generating a rotational movement The operating cycle begins when the piston 506 is at its highest position as shown in Figure IB. When the piston 506 is in its highest position, the valve is open and air can pass from the surrounding atmosphere, through the third passageway, through the first passageway and then through the second passageway and into the compression chamber 510. As such, air from the surrounding atmosphere enters the compression chamber 510 until the pressure of the air within the compression chamber 510 is the same as that of the surrounding atmosphere. It will be appreciated that the free end of the third passageway could be connected to a gas source (e.g. a gas storage tank) which is capable of supplying a specific gas e.g. an inert gas. In addition or as an alternative, there could be a mixer capable of the mixing air or the gas with a fluid or solids (ideally powdered), the fluid potentially having dissolved solids (such as sea water) prior to the air or gas entering the third passageway. The operating cycle continues when the piston is moved by the crank shaft from its highest position as shown in Figure IB to its lowest position as sown in Figure 1A. During this part of the operating cycle, the compression chamber 510 is completely sealed (with the valves being closed) with the air within the chamber being prevented from exiting the compression chamber 510 as the piston 506 moves between its highest position to its lowest position. When the piston 506 is being moved downwardly, the volume of the compression chamber 510 is reduced. Therefore, as the piston 506 moves downwardly, the air located in the compression chamber 510 becomes compressed, with both the pressure and temperature of the air within the compression chamber 510 increasing. The force required to move the piston 506 in order to compress the air is provided by the rotation of the crank shaft. If there are any fluids within the air, the temperature of the fluid also increases. This results in the fluid evaporating. The operating cycle continues when the piston 506 reaches its lowest position as shown in Figure 1A. When the piston 506 is in its lowest position, the valve is open and the compressed heated gas, can pass from the compression chamber 510, through the second passageway, through the first passageway and then through the fourth passageway and then exiting. The mechanical compressor can be connected to either a mechanical compression pulse spray dryer such as one disclosed in WO23161599 or a separation device such as one disclosed in GB2619110 by connecting the fourth passageway to such a device. As the air within the compression chamber 510 has increased pressure and temperature, the air is emitted from the fourth passageway as a pulse of compressed and heated gas. Once the air has been emitted as a pulse, the pressure of the remaining air within the compression chamber 510 is reduced and is likely to be similar to that of the surrounding atmosphere. The operating cycle continues when the piston 506 is moved by the crank shaft from its lowest position as shown in Figure 1A to its highest position as shown in Figure IB. During this part of the operating cycle, the compression chamber 510 is completely sealed as the valves are closed with the air within the chamber being prevented from exiting the compression chamber 510 as the piston 506 moves between its lowest position to its highest position. When the piston 506 is being moved downwardly, the volume of the compression chamber 510 is increased. Therefore, as the piston 506 moves upwardly, the air located in the compression chamber 510 reduces in pressure. The force required to move the piston 506 is provided by the rotation of the crank shaft. When the piston 506 reaches its highest position as shown in Figure IB, the pressure inside of the compression chamber 510 is significantly reduced. As the valve is open, air can be drawn into the compression chamber when the piston reaches its highest position and air is able to be drawn into the compression chamber from the surrounding atmosphere (which would be at a higher pressure). Once the piston 506 has returned to its highest position shown in Figure IB, the operating cycle of the mechanical compressor 484 is repeated as the crank shaft 412 continues to rotate. Each 360 degree rotation of the crank shaft results in a single operating cycle of the mechanical compressor, with the piston traveling down and up once. Each operating cycle results in the mechanical compressor generating of a single pulse of compressed heated air. 2nd EMBODIMENT The second embodiment of the invention will now be described with reference to Figures 2A and 2B. Where the same features are present in the second embodiment which were present in the first embodiment, the same reference numbers have been used. Figures 2A and 2B show a mechanical compressor comprising a piston compressor which produces a series of pulses of compressed hot air. The compressed hot air can also include vapourised fluid and / or solids. The piston compressor comprises a cylinder block 500 which is mounted below a crank shaft housing (not shown). The cylinder block 500 comprises an elongate cylinder 504 having a longitudinal axis and a uniform circular cross section, in a direction perpendicular to the axis, along the length of the cylinder 504. Slideably mounted within the cylinder 504 is a piston 506 of circular cross section of similar size but slightly smaller to that of the cylinder 504. Mounted circumferentially around the internal wall of the cylinder 504 are three seals 602 to 606 which each form a seal between the external sidewall of the piston 506 and the inner side wall of the cylinder 504 and which prevent any gases from passing the seals 602-604. The seals 602 -606 slide along the external sidewall of the piston 506 when the piston 506 reciprocates within the cylinder 504. The three seals 602 - 606 are each in the form of an O ring, each of which surrounds the piston 506 and which are each located in a circumferential groove (not shown) formed around the internal wall of the cylinder 504 in well-known manner. The locations of the O rings remain fixed in relation to the cylinder 504. The upper section of the cylinder 504 opens into a chamber (not shown) formed inside of the crank shaft housing (not shown). The lower section of cylinder 504 forms a compression chamber 510, the compression chamber 510 being defined by the internal walls at the end of the cylinder 504 and an end surface 517 of the piston 506. A rotatable crank shaft (not shown) is mounted inside of the chamber within the crank shaft housing which is capable of rotating about an axis which extends perpendicularly to the longitudinal axis of the cylinder 504. A connecting rod 514 is pivotally attached to the crank shaft at one end, the axis of pivot being parallel to but eccentrically off set from the axis of rotation of the crank shaft. The other end of the connecting rod 514 is pivotally attached to the piston 506, the axis of pivot being parallel to the axis of rotation of the crank shaft. Rotation of the crank shaft results in a linear reciprocation motion of the piston 506 inside the cylinder 504 along the longitudinal axis of the cylinder 504 in well-known manner. A counterweight (not shown) is eccentrically mounted on the crank shaft to counteract any vibrations generated by the eccentric connection of the connecting rod 514 as the crank shaft rotates. The first O ring 602 is located adjacent the lower end of a first passageway which is in the form of a groove 608 which formed in the wall of the internal wall of the cylinder 504. The groove 608 extends vertically from a position just above the first O ring 602 to the top of the cylinder 504 where it connects to the chamber within the crank shaft housing as shown in Figures 2A and 2B. The open side of the groove 608 faces towards and connects with the cylinder 504 and forms a passageway between the lower end of the groove 608 and the crank shaft housing, along which air can pass. The chamber within the crank shaft housing is connected to the surrounding atmosphere and therefore the air within the crank shaft housing is filled by the surrounding atmosphere. The second 0 ring 604 is located immediately above a first aperture 612 which is formed in the internal wall of the cylinder 504 and which forms one end of a second passageway which is in the formed inside of the cylinder block 500. The second passageway is in the form of a straight channel 610. The other end of the channel 610 connects to an input of either a pulse sprayer or a separator. The third O ring 606 is located immediately below the first aperture 612. Formed inside of the piston 506 is a T shaped passageway. The T shaped channel comprises three straight channels 614 - 618. One end of the first channel 614 opens to a second aperture 620 formed in the side wall of the piston 506. The other end of the first channel 614 ends at a central point 622. One end of the second channel 616 opens to a third aperture 624 formed in the side wall of the piston 506. The other end of the second channel 616 ends at the central point 622. The first and second channels 614, 616 both extend horizontally in the same direction as each other and are co-axial with each other. The second and third apertures 620,624 are located on the side wall of the piston 506 at the same axial position along the length of the piston 506 but radially at 180 degrees from each other around the longitudinal axis of the cylinder 504 as shown in Figures 2A and 2B. The third channel 618 extends from the central point 622 perpendicularly to the first and second channels 614,616. The third channel 618 opens to a fourth aperture 626 formed In the wall 517 of the piston 506 which forms a wall of the compression chamber 510. As such, air from compression chamber 510 can freely pass into the third cannel 618 through the fourth aperture and vice versa regardless of the position of the piston 506 within the cylinder 504. Air is only able to enter or exit the compression chamber 510 via the third channel. The central point 622 allows air to pass freely between the first, second and third passageways, as such, air can freely move along and between the three channels 614, 616, 618. When the piston 506 is in its highest position as shown in in Figure 2B, the second and third apertures 620,624 of the T shaped passageway are located above the first O ring 602 so that the second aperture 620 faces towards the lower end of the groove 608. As such, air can pass between the first channel 614 of the T shaped passageway and the groove 608 of the first passageway. The first aperture 512 of the second passageway faces the side wall of the piston 506 between the second and third O rings 604,606. As such, the first aperture is sealed thus preventing any air from passing along the second passageway. Therefore, when the piston 506 is in its highest position as shown in in Figure 2B, air can pass from the surrounding atmosphere, along the first passageway, through the first and third channels of the T shaped passageway and then into the compression chamber 510. The second passageway 610 remains blocked. When the piston 506 is in its lowest position as shown in in Figure 2A, the second and third apertures 620,624 of the T shaped passageway are located below the first O ring 602 and between the second and third O rings so that the third aperture 624 faces towards the first aperture 612 of the second passageway. As such, air can pass between the first and second channels of the T shaped passageway and the second passageway 610. The groove 608 of the first passageway faces the side wall of the piston 506 above the first 0 ring 602. As such, air is prevented from passing from the first passageway into the T shaped passageway. Therefore, when the piston 506 is in its lowest position as shown in in Figure 2B, air can pass from the compression chamber 510, through the T shape passageway, through the first passageway 610 and then is capable of passing into either a mechanical compression pulse spray dryers such as one disclosed in WO23161599 or a separation devices disclosed in GB2619110 assuming the fourth passageway is connected to such a device. When the piston 506 is moving between its highest position to its lowest position and vice versa, the second and third apertures 620,624 of the first and second channels of the T shaped passageway are located between the first and second O rings. As such, the T shaped passageway is sealed, resulting the third channel being sealed. As such, the compression chamber 510 is sealed with air prevented from entering or exiting the compression chamber 510 when the piston 506 is moving between its highest position to its lowest position and vice versa. The operating cycle of the first embodiment of the mechanical compressor will now be described with reference to Figures 2A and 2B. In order for the mechanical compressor to operate to produce a series of pulses of compressed hot air, the crank shaft must be rotationally driven by an external rotary force to move the piston 506 up and down within the cylinder. Such a force can be generated by a separate fan or propellor (not shown) due to the movement of air or water through the fan or propellor such as wind acting on a wind turbine or sea water passing through a water turbine due to the movement of the water caused by the tide. Alternatively, the force could be generated by an electric motor (not shown), a pneumatic motor (not shown), a hydraulic motor (not shown), a petrol or diesel engine (not shown) or any known device which is capable of generating a rotational movement The operating cycle begins when the piston 506 is at its highest position as shown in Figure 2B. When the piston 506 is in its highest position, gas, which in this case is air, can pass from the surrounding atmosphere, along the first passageway, through the T shaped passageway and then and into the compression chamber 510. As such, air from the surrounding atmosphere enters the compression chamber 510 until the pressure of the air within the compression chamber 510 is the same as that of the surrounding atmosphere. It will be appreciated a gas source (e.g. a gas storage tank) which is capable of supplying a specific gas e.g. an inert gas, can be connected to the chamber of the crank housing. In addition or as an alternative, there could be a mixer capable of mixing the air or the gas with a fluid or solids (ideally powdered), the fluid potentially having dissolved solids (such as sea water) prior to the air or gas entering the chamber 510. The operating cycle continues when the piston is moved by the crank shaft from its highest position as shown in Figure 2B to its lowest position as sown in Figure 2A. During this part of the operating cycle, the compression chamber 510 is completely sealed with the air within the chamber being prevented from exiting the compression chamber 510 as the piston 506 moves between its highest position to its lowest position. When the piston 506 is being moved downwardly, the volume of the compression chamber 510 is reduced. Therefore, as the piston 506 moves downwardly, the air located in the compression chamber 510 becomes compressed, with both the pressure and temperature of the air within the compression chamber 510 increasing. The force required to move the piston 506 in order to compress the air is provided by the rotation of the crank shaft. If there are any fluids within the gas, the temperature of the fluid also increases. This results in the fluid evaporating. The operating cycle continues when the piston 506 reaches its lowest position as shown in Figure 2A. When the piston 506 is in its lowest position, the compressed heated gas, can pass from the compression chamber 510, through the T shaped passageway, through the second passageway 610 and then exit. The mechanical compressor can be connected into either a mechanical compression pulse spray dryers such as one disclosed in WO23161599 or a separation device disclosed in GB2619110 by connecting the second passageway to such a device. As the air within the compression chamber 510 has increased pressure and temperature, the air is emitted from the second passageway as a pulse of compressed and heated gas. Once the air has been emitted as a pulse, the pressure of the remaining air within the compression chamber 510 is reduced and is likely to be similar to that of the surrounding atmosphere. The operating cycle continues when the piston 506 is moved by the crank shaft from its lowest position as shown in Figure 2A to its highest position as sown in Figure 2B. During this part of the operating cycle, the compression chamber 510 is completely sealed with the air within the chamber being prevented from entering or exiting the compression chamber 510 as the piston 506 moves between its lowest position to its highest position. When the piston 506 is being moved upwardly, the volume of the compression chamber 510 is increased. Therefore, as the piston 506 moves upwardly, the air located in the compression chamber 510 reduces in pressure. The force required to move the piston 506 is provided by the rotation of the crank shaft. When the piston 506 reaches its highest position as shown in Figure 2B, the pressure inside of the compression chamber 510 is significantly reduced. This causes air to be drawn into the compression chamber 510 when the piston 506 reaches its highest position and air is able to be drawn into the compression chamber 510 from the surrounding atmosphere (which would be at a higher pressure). Once the piston 506 has returned to its highest position shown in Figure 2B, the operating cycle of the mechanical compressor 484 is repeated as the crank shaft 412 continues to rotate. Each 360 degree rotation of the crank shaft results in a single operating cycle of the mechanical compressor, with the piston traveling down and up once. Each operating cycle results in the mechanical compressor generating of a single pulse of compressed heated gas. 3ro EMBODIMENT A third embodiment of the present invention will now be describe with reference to Figures 3A to 3D. The third embodiment is based on the design of a KKM Wankel engine. In the third embodiment, a "Wankel engine" acts as a mechanical compressor. However, in contrast to a Wankel engine where the rotor is driven by the compression and combustion of aerated fuel which in turn rotatingly drives a shaft on which it is mounted, the rotor 700 is rotationally driven via the shaft, the rotating rotor compressing air within the shaped housing as it rotates. Referring to Figure 3A, the rotary mechanical compressor comprises a rotor 700 mounted on a shaft 704 via an eccentric lobe (not shown) and engages with the shaft 704 via gear teeth (not shown). The rotor 700 rotates within the shaped housing 702 compressing air located within pockets 706 to 710 formed between the rotor 700 and the inner wall of the shaped housing 702, the construction of the rotor 700, shaft 704 and shaped housing 702 and their relative movement is the same as that of a Wankel engine, the construction of which is well known, and therefore will not be described in any further detail. In order for the mechanical compressor to operate to produce a series of pulses of compressed hot air, the shaft 704 must be rotationally driven by an external rotary force to move the rotor 700 within the shaped housing 702. Such a force can be generated by a separate fan or propeller (not shown) due to the movement of air or water through the fan or propellor such as wind acting on a wind turbine or sea water passing through a water turbine due to the movement of the water caused by the tide. Alternatively, the force could be generated by an electric motor (not shown), a pneumatic motor (not shown), a hydraulic motor (not shown), a petrol or diesel engine (not shown) or any known device which is capable of generating a rotational movement. Referring to Figures 3A to 3D, an air inlet pipe 712 is attached to one side of the shaped housing 702. The inlet pipe 712 connects between the chamber inside of the shaped housing 702 and the surrounding atmosphere, the pipe 712 enables air to enter the shaped housing 702. Referring to Figures 3A to 3D, an air outlet pipe 714 is attached to one side of the shaped housing 702. The outlet pipe 714 connects between the chamber inside of the shaped housing 702 and an outlet device, for example, mechanical compression pulse spray dryers such as one disclosed in WO23161599 or separation devices disclosed in GB2619110 by connecting the outlet pipe 714 to such a device. Referring to Figures 3A to 3D, three air pockets 706, 708,710 are formed between the sides of the rotor 700 and the inner wall of the shaped housing 702. The air pockets rotate within 706, 708,710 the shaped housing 702 as the rotor 700 rotates. The air pockets 706, 708,710 will be given reference letter as a, b, c and d as they pass through the four positions of the operating cycle. The operating cycle will now be described. Referring to Figure 3A, air enters the The operating cycle begins when the rotor 700 is in the position shown in Figure 3A. When it is in this position, air can pass from the surrounding atmosphere, along the inlet pipe 712 and into the first air pocket 706a. As such, air from the surrounding atmosphere enters the pocket 706a until the pressure of the air within the first air pocket 706a is the same as that of the surrounding atmosphere. The operating cycle continues when the rotor 700 is moved by the shaft 704 to the position shown in Figure 3B. During this part of the operating cycle, the first pocket 706b is completely sealed with the air within the first pocket 706b being prevented from exiting the first air pocket 706b. As the rotor 700 rotates, the volume of the first air pocket 706 is reduced. Therefore, as the rotor 700 rotates, the air located in the first air pocket 706b becomes compressed, with both the pressure and temperature of the air within the first air pocket 706b increasing. The operating cycle continues when the rotor 700 reaches the position shown in Figure 3C. In this position, the compressed heated gas, can pass from the first air pocket 706c, through the air outlet pipe and then exit. It the air outlet pipe 714 is connected into either a mechanical compression pulse spray dryers such as one disclosed in WO23161599 or a separation device disclosed in GB2619110, then the air can pass into these devices. As the air within the first air pocket 706c has increased pressure and temperature, the air is emitted from the air outlet pipe 714 a pulse of compressed and heated gas. Once the air has been emitted as a pulse, the pressure of the remaining air within the first air pocket 706c is reduced and is likely to be similar to that of the surrounding atmosphere. The operating cycle continues when the rotor 700 is at the position shown in Figure 3D. During this part of the operating cycle, the first compression pocket 706c is completely sealed with the air being prevented from entering or exiting the first air pocket 706c as the rotor rotates. As the rotor continues to rotate, the volume of the first air pocket 706c is increased. Therefore, as the rotor 700 rotates, the air located in the first air pocket 706c reduces in pressure. When the rotor returns to the position shown in Figure 3A, the pressure inside of the first air pocket is significantly reduced. This causes air to be drawn into the first air pocket 706a from the surrounding atmosphere (which would be at a higher pressure). Each air pocket 706,708, 710 performs the same operating cycle, the operating cycle of each air pocket 706,708, 710 being 120 degrees out of synchronization with adjacent air pockets706,708,710. Once the rotor 700 has returned to the position shown in Figure 3A, the operating cycle of the mechanical compressor is repeated. Each 360 degree rotation of the rotor results in the mechanical compressor generating of three pulses of compressed heated gas. It should be noted that the movement of the rotor 700 inside of the shaped housing 702 acts as a valve to allow air into or out of the air pockets 706, 708, 710, the relative movement opening and closing the valves, their relative position acting as a timer. When the rotor 700 is in the appropriate position, the valve is open allowing compressed air out of the air pockets in the form of a pulse.

Claims

1 A compression mechanism for a mechanical compression pulse spray dryer or a separation device comprising:a cylinder block (500) which forms a cylinder (504);a piston (506) slideably mounted within the cylinder (504) such that the piston (506) and cylinder (504) can move relative to each other;a compression chamber (510) formed between the piston (506) and cylinder (504), the volume of which alters depending on the position of the piston (506) within the cylinder (504);at least one valve which allows a gas to enter and / or exit the compression chamber (510);wherein the cylinder block (500) and the piston (506) form the at least one valve.2 A compression mechanism as claimed in claim 1 wherein the position of the piston (506) within the cylinder (504) determines whether the at least one valve is open or closed.3 A compression mechanism as claimed in either of claims 1 or 2 wherein the relative movement of piston inside of the cylinder acts as a timing device, its movement opening and closing the at least one valve as the piston slides within the cylinder.4 A compression mechanism as claimed in any of the previous claims wherein the pressure of the gas when it enters the compression chamber is substantially less than when it exits the compression chamber and the temperature of the gas when it enters the compression chamber is substantially less than when it exits the compression chamber.5 A compression mechanism as claimed in any of the previous claims wherein the at least one valve allows the gas to exit the compression chamber when the gas has been compressed and the pressure and temperature of the gas has been increased, and preferably, in the form of a pulse.6 A compression mechanism as claimed in any of the previous claims wherein:• a first set of passageways are formed in the piston;• a second set of passageways formed in the cylinder block (500);wherein the piston can move between:at least one first position within the cylinder where at least part of the first set of passageways of the piston aligns with at least part of the second set of passageways of the cylinder block to form a first conduit between the compression chamber and a gas supply; andat least one second position within the cylinder where at least part of the first set of passageways of the piston aligns with at least part of the second set of passageways of the cylinder block to form a second conduit between the compression chamber and an external device.7 A compression mechanism as claimed in claim 6 wherein, when the piston is located between its first position and its second position; the first set of passageways and second set passageways are located relative to each other such that the compression chamber is sealed so that gas can neither enter nor exit the compression chamber.8 A compression mechanism as claimed in either of claims 6 or 7 wherein each of the passageways within the piston or cylinder block is either a groove or a channel.9 A compression mechanism as claimed in any of claims 6 to 8 wherein there is a plurality of seals located between the sides of the piston and the walls of the cylinder which restrict the movement of a gas between the sides of the piston and the walls of the cylinder.10 A compression mechanism as claimed in claim 9 wherein the plurality of seals:1) aid in the formation of the first conduit when the piston is in its at least one first position in the cylinder; and / or2) aid in the formation of the second conduit when the piston is in its at least one second position in the cylinder; and / or and3) aid in the sealing of the compression chamber when the piston is located between its at least one first position and its at least one second position.11 A compression mechanism for a mechanical compression pulse spray dryer or a separation device comprising:a shaped housing which forms a chamber;a rotor moveably mounted within the chamber such that the rotor can move in a rotational manner within the chamber;at least one air pocket formed between the rotor and shaped housing, the volume of which alter depending on the position of the rotor within the shaped housing;at least one opening which allows a gas to enter and / or exit the at least one air pocket;wherein the relative position of the rotor within the shaped housing determines whether the at least one opening is open or closed.12 A compression mechanism as claimed in claim 11 wherein the relative movement of rotor inside of the shaped cylinder acts as a timing device, its movement opening and closing the at least one opening as the rotor moves in a rotational manner within the shaped housing.13 A compression mechanism as claimed in claims 11 or 12 wherein the pressure of the gas when it enters the at least one air pocket is substantially less than when it exits the at least one air pocket and the temperature of the gas when it enters the at least one air pocket is substantially less than when it exits the at least one air pocket.14 A compression mechanism as claimed in any of claims 11 to 13 wherein the gas exits the at least one air pocket when the gas has been compressed and the pressure and temperature of the gas has been increased, and preferably, in the form of a pulse.Application No: GB2410330.1Examiner: Dr Nicholas WigleyClaims searched: 1-10Date of search: 27 March 2025Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-10 GB 2619110 A (BELL) See whole document, especially Figures 4A-D, noting valve 486 X 1-10 US 2013 / 189140 Al (KABIR et al) See whole document, especially Figures 7 &8 and paragraphs 0049-0052 X 1-10 JP H07208325 A (TOYO INK MFG CO) See whole document, especially Figures 3 &4 and paragraphs 0011-0013 &0016-0019 X 1-5 US 2006 / 083647 Al (MOODY et al) See whole document, especially Figures 3 &4 and paragraph 0040 X 1-5 DE 2006824 Al (STELZER) See whole document, especially Figures 1 &2 noting outlet 22, piston channel 20 and inlet 18Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From F04B 0007 / 04 01 / 01 / 2006 F04B 0039 / 00 01 / 01 / 2006 F04B 0039 / 08 01 / 01 / 2006 F04B 0039 / 10 01 / 01 / 2006 F01C 0001 / 22 01 / 01 / 2006

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