Fluid access system for compressor sealing

Abstract

A rotary shaft machine (100) comprising a fluid access system for providing activation and / or deactivation of a first sealing member (250A, 250B, 250C, 250D) within the machine (100), the machine (100) comprising: a machine housing (210) comprising: a first housing fluid access channel (254'') within the machine housing (210); and a first external fluid access port (213) configured to provide fluid communication from outside of the machine housing (210) to the first housing fluid access channel (254''); a first fluid-activatable sealing component (250) in fluid communication with the first housing fluid access channel (254'') and comprising at least a first sealing member (250A, 250B, 250C, 250D) movable between an unsealed position and a sealed position; and a rotary shaft (220) arranged to pass from outside of the machine housing (210) to inside of the machine housing (210) through the first fluid-activatable sealing component (250); wherein in the unsealed position the first sealing member (250A, 250B, 250C, 250D) does not seal the rotary shaft (220) and in the sealed position the first sealing member (250A, 250B, 250C, 250D) forms a fluid tight seal with the rotary shaft (220); such that the first sealing member (250A, 250B, 250C, 250D) can be moved to seal around the rotary shaft (220) and / or to break sealing around the rotary shaft (220) by providing or evacuating fluid to or from the first external fluid access port (213) on the machine housing (210).

Description

[0001] FLUID ACCESS SYSTEM FOR COMPRESSOR SEALING

[0002] FIELD

[0003] The present invention relates to a fluid access system for activating or deactivating at least one sealing component in an industrial system utilising a rotating shaft.

[0004] BACKGROUND

[0005] In various machines it is required to provide sealing of a rotating shaft. Often the seals are arranged in a so-called cartridge, where they can be removed from the rotating shaft for maintenance or replacement. This is often needed if the seals wear due to contact with the rotating shaft and no longer provide sufficient sealing performance. Typically, a rotating shaft may be extending into one machine from an electric motor for example. In this connection, internally in the machine there may be provided a reservoir of lubricant. It is highly desirable to maintain the seals without draining and refilling the lubricant, as this is time consuming and expensive.

[0006] Many types of shaft seals employ inflatable or hydraulically expandable seals. The seals are provided at a connection between the electric motor and the machine receiving the rotatable shaft from the electric motor. This point is not always easily accessible, therefore the fluid communication ports required to operate (i.e. inflate / deflate, pressurise / depressurise) the seals are often not easily accessible. They therefore require either disassembly of the housing or facias covering the ports, or they require the provision of fluid communication lines running from the seals to another point where connection of a pump, hydraulic fluid line etc may be easier than close to the seal. It is highly undesirable to have many fluid communication lines running in the internal volumes of the housing. Firstly, the fluid communication lines take up valuable space within the housing. Additionally, the fluid communication lines may become tangled around each other or around other equipment within the housing. Additionally, it is time consuming and may require training to dismantle the housing to access the fluid communication lines.

[0007] In machines such as heat pumps, compressors are employed. Many heat pumps have a gas / vapor compressor as a core component. More specifically, for the vapor compression cycle, which is commonly used for, among other, residential heat pumps, refrigerators and air conditioning systems in cars, as well as for industrial heat pumps, the compressor is a central component. The main advantages of using heat pumps as opposed to conventional boiler or furnace systems, is that heat pumps generate several more times the heat than the power which is required to drive them, thereby increasing energy efficiency, and in many cases also improving economics of operation.

[0008] In the example described herein, a heat pump is described which comprises a compressor. However, it should be noted that the present disclosure is not limited to only heat pumps or heat pumps comprising compressors, and that it may be equally relevant and useful to other types of machines with similar requirements.

[0009] Therefore, there is a need to provide an easy access to the seals within the housing. There is another need to provide easy access to the fluid communication ports without disassembly of the housing or facias covering the ports.

[0010] Yet another need is to activate and deactivate the seal without opening the access hatch to gain access to the internal volume of the housing.

[0011] There is also a need to eliminate or reduce many fluid communication lines running in the internal volumes of the housing.

[0012] Patent Document US3556697A discloses in a vacuum pump including a housing having an end wall, a bore in said end wall, a shaft extending through said bore, and means in said housing produce subatmospheric pressure therein; a seal formed between the inner periphery of said bore and the associated outer periphery of said shaft to minimize flow of air from the exterior of said housing through said seal and into the interior of said housing; a supply of sealing liquid; and conducting means communicating said supply of sealing liquid with said seal to permit said liquid to be drawn through said seal by said subatmospheric pressure in said housing preventing air from entering said housing through said seal; wherein said seal is in the form of a labyrinth seal including two concentric sleeves disposed in said bore, one of said sleeves mounted on said shaft and rotatable therewith, the other of said sleeves mounted in said bore to be stationary relative to said one of said sleeves, and one of said sleeves having its outer periphery ridged and formed of a material harder than the material of said other of said sleeves and spaced in close sealing relationship with said other of said sleeves. Patent document US2010013167A1 discloses a sealing arrangement for the sealed leadthrough of rotating shafts through housing bores of housings comprising at least one lip seal with a sealing lip that faces toward the area normally under higher pressure. In order to extend substantially the area of application of sealing arrangements with lip seals and by doing so, to make use of the sealing arrangement to achieve its advantages of being more economical, more durable also at pressure peaks, easier to install, and easier to maintain, also at higher pressures and pressure fluctuations, the lip seal on the side facing the area with higher pressure is under a constant pressure that is higher than the highest pressure occurring inside the housing, and a gap that throttles the outflow is provided between this area and the inside of the housing.

[0013] Patent document JP2007132243A discloses a screw compressor which compresses target gas by screw rotors contained in a rotor chamber and meshed with each other. In the screw compressor, a non-contact sea is provided between the screw rotor and a discharge side bearing of a rotor shaft of the screw rotor , a lip seal is provided between the non-contact seal and the bearing of the rotor shaft and a communication passage is provided for bringing a space between the non-contact seal and the lip seal in communication with a space of lower pressure than durable pressure of the lip seal.

[0014] Patent Document US2015152966A1 discloses a shaft seal assembly for sealing along a rotor shaft. The shaft seal assembly includes a seal housing, annular inner and outer seal members, an annular middle element, and an end plate. The seal housing has a seal member bore and a shaft bore. The annular inner and outer seal members are configured to be disposed in the seal member bore. The middle element is disposed between the inner seal member and the outer seal member within the seal member bore. The end plate is attached to the seal housing and covers a portion of the seal member bore. The middle element biases the inner seal member against the seal housing and biases the outer seal member against the end plate.

[0015] At least one aim of the present invention is to obviate or at least mitigate one or more drawbacks associated with the prior art.

[0016] SUMMARY

[0017] According to a first aspect of the invention, there is provided a rotary shaft machine comprising a fluid access system for providing activation and / or deactivation of a first sealing member within the machine, the machine comprising: a machine housing comprising: a first housing fluid access channel within the machine housing; and a first external fluid access port configured to provide fluid communication from outside of the machine housing to the first housing fluid access channel; a first fluid-activatable sealing component in fluid communication with the first fluid access channel and comprising at least a first sealing member movable between an unsealed position and a sealed position; and a rotary shaft arranged to pass from outside of the machine housing to inside of the machine housing through the fluid-activatable sealing component; wherein in the unsealed position the first sealing member does not seal the rotary shaft and in the sealed position the first sealing member forms a fluid tight seal with the rotary shaft; such that the first sealing member can be moved to seal around the rotary shaft and / or to break sealing around the rotary shaft by providing or evacuating fluid to or from the first external fluid access port on the machine housing.

[0018] This may provide easy access to the seals within the housing. This may provide easy access to the fluid communication ports without disassembly of housings or facias covering the ports.

[0019] Activation and deactivation of the seals may be performed without opening the access hatch to gain access to the internal volume of the housing.

[0020] Elimination or reduction of fluid communication lines running in the internal volumes of the housing may be obtained.

[0021] The first fluid-activatable sealing component may further comprise a first sealing member fluid communication channel configured to provide fluid communication between the first housing fluid access channel and the first sealing member.

[0022] The first external fluid access port may be configured to receive positive and negative pressure such that the first sealing member can be activated and deactivated.

[0023] The first fluid activatable sealing component may be a cartridge seal.

[0024] The machine housing may further comprise: a second housing fluid access channel within the machine housing and in fluid communication with the first fluid-activatable sealing component; and a second external fluid access port configured to provide fluid communication from outside of the machine housing to the second housing fluid access channel; such that the first sealing member can be moved to seal around the rotary shaft by providing fluid to the second external fluid access port on the machine housing.

[0025] The first fluid-activatable sealing component may further comprise a second sealing member fluid communication channel configured to provide fluid communication between the second housing fluid access channel and the first sealing member.

[0026] The second external fluid access port may be configured to receive positive pressure such that the first sealing member can be activated.

[0027] The machine housing may further comprise: a third housing fluid access channel within the machine housing and in fluid communication with the first fluid-activatable sealing component; and a third external fluid access port configured to provide fluid communication from outside of the machine housing to the third housing fluid access channel; such that the first sealing member can be moved to break sealing around the rotary shaft by evacuating fluid from the third external fluid access port on the machine housing.

[0028] The first fluid-activatable sealing component may further comprise a third sealing member fluid communication channel configured to provide fluid communication between the third housing fluid access channel and the first sealing member.

[0029] The third external fluid access port may be configured to receive negative pressure such that the first sealing member can be deactivated.

[0030] The rotary shaft machine may further comprise a second sealing component configured to seal the machine housing, wherein the second sealing component is located between the machine housing the first activatable sealing component, and the rotary shaft is arranged to pass from outside of the machine housing to inside of the machine housing through the second sealing component.

[0031] The second sealing component may be an end cap.

[0032] The second sealing component may further comprise a first connecting fluid communication channel fluidly connecting the first housing fluid access channel with the first activatable sealing component.

[0033] The second sealing component may further comprise a first connecting fluid communication channel fluidly connecting the first housing fluid access channel with the first sealing member fluid communication channel.

[0034] The second sealing component may further comprise a second connecting fluid communication channel fluidly connecting the second housing fluid access channel with the first activatable sealing component.

[0035] The second sealing component may further comprise a second connecting fluid communication channel fluidly connecting the second housing fluid access channel with the second sealing member fluid communication channel.

[0036] The second sealing component may further comprise a third connecting fluid communication channel fluidly connecting the third housing fluid access channel with the first activatable sealing component.

[0037] The second sealing component may further comprise a third connecting fluid communication channel fluidly connecting the third housing fluid access channel with the third sealing member fluid communication channel. The rotary shaft machine may be further configured for providing activation and / or deactivation of a second sealing member within the machine, the machine further comprising: a fourth housing fluid access channel within the machine housing; and a fourth external fluid access port configured to provide fluid communication from outside of the machine housing to the fourth housing fluid access channel; wherein the second sealing component further comprises: a second fluid-activatable sealing component in fluid communication with the fourth fluid access channel and comprising at least a second sealing member movable between an unsealed position and a sealed position; wherein the rotary shaft is arranged to pass from outside of the machine housing to inside of the machine housing through the second activatable sealing component; wherein in the unsealed position the second sealing member does not contact the rotary shaft and in the sealed position the second sealing member contacts and forms a fluid tight seal with the rotary shaft; such that the second sealing member can be moved to seal around the rotary shaft and / or to break sealing around the rotary shaft by providing or evacuating fluid to or from the fourth external fluid access port on the machine housing.

[0038] The second fluid-activatable sealing component may further comprise a fourth sealing member fluid communication channel configured to provide fluid communication between the fourth housing fluid access channel and the second sealing member.

[0039] The fourth external fluid access port may be configured to receive positive and negative pressure such that the second sealing member can be activated and deactivated.

[0040] The machine housing may further comprise: a fifth housing fluid access channel within the machine housing and in fluid communication with the second fluid-activatable sealing component; and a fifth external fluid access port configured to provide fluid communication from outside of the machine housing to the fifth housing fluid access channel; such that the second sealing member can be moved to seal around the rotary shaft by providing fluid to the fifth external fluid access port on the machine housing.

[0041] The second fluid-activatable sealing component may further comprise a fifth sealing member fluid communication channel configured to provide fluid communication between the fifth housing fluid access channel and the second sealing member.

[0042] The fifth external fluid access port may be configured to receive positive pressure such that the second sealing member can be activated.

[0043] The machine housing may further comprise: a sixth housing fluid access channel within the machine housing and in fluid communication with the second fluid-activatable sealing component; and a sixth external fluid access port configured to provide fluid communication from outside of the machine housing to the sixth housing fluid access channel; such that the second sealing member can be moved to break sealing around the rotary shaft by evacuating fluid from the sixth external fluid access port on the machine housing.

[0044] The second fluid-activatable sealing component may further comprise a sixth sealing member fluid communication channel configured to provide fluid communication between the sixth housing fluid access channel and the second sealing member.

[0045] The sixth external fluid access port may be configured to receive negative pressure such that the second sealing member can be deactivated.

[0046] The first fluid-activatable sealing component may be configured to provide sealing of a rotating shaft in use.

[0047] Alternatively, the first fluid-activatable sealing component may be configured to provide sealing of a stationary shaft in use.

[0048] The second fluid-activatable sealing component may be configured to provide sealing of a stationary shaft in use.

[0049] Alternatively, the second fluid-activatable sealing component may be configured to provide sealing of a rotating shaft in use.

[0050] The machine housing may be a compressor block configured to be substantially filled with lubricant in use.

[0051] According to a second aspect of the invention, there is provided a kit for assembling a rotary shaft machine comprising a fluid access system for providing activation and / or deactivation of a first sealing member within the machine, the kit comprising: a machine housing comprising: a first housing fluid access channel within the machine housing; and a first external fluid access port configured to provide fluid communication from outside of the machine housing to the first housing fluid access channel; a first fluid-activatable sealing component configured to be in fluid communication with the first fluid access channel in use and comprising at least a first sealing member movable between an unsealed position and a sealed position; and a rotary shaft configured to pass from outside of the machine housing to inside of the machine housing through the first fluid-activatable sealing component in use; wherein when assembled, in the unsealed position the first sealing member does not seal the rotary shaft and in the sealed position and first sealing member forms a fluid tight seal with the rotary shaft; such that the first sealing member can be moved in use to seal around the rotary shaft and / or to break sealing around the rotary shaft by providing or evacuating fluid to or from the first external fluid access port on the machine housing.

[0052] The kit may further comprise a second sealing component configured to seal the machine housing wherein the second sealing component is configured to be located in use between the machine housing and the first activatable sealing component, and the second sealing component is configured such that the rotary shaft can pass from outside of the machine housing to inside of the machine housing through the second sealing component in use.

[0053] The second sealing component may further comprise a first connecting fluid communication channel configured to fluidly connect the first housing fluid access channel with the first activatable sealing component when the kit is assembled.

[0054] According to a third aspect of the invention, there is provided a method of assembling a rotary shaft machine comprising a fluid access system for providing activation and / or deactivation of a first sealing member within the machine, the method comprising the steps of: providing a machine housing comprising: a first housing fluid access channel within the machine housing; and a first external fluid access port configured to provide fluid communication from outside of the machine housing to the first housing fluid access channel; providing a first fluid- activatable sealing component comprising at least a first sealing member movable between an unsealed position and a sealed position; providing a rotary shaft; arranging the first fluid-activatable sealing component in fluid communication with the first fluid access channel; arranging the rotary shaft to pass from outside of the machine housing to inside of the machine housing through the fluid-activatable sealing component such that: in the unsealed position the first sealing member does not seal the rotary shaft and in the sealed position and first sealing member forms a fluid tight seal with the rotary shaft; and such that when fluid is provided or evacuated from the first external fluid access port on the machine housing, the first sealing member is moved to seal around the rotary shaft and / or break sealing around the rotary shaft.

[0055] According to a fourth aspect of the invention, there is provided a method of operating a fluid access system to activate a first sealing member within the machine, the method comprising the steps of: providing a rotary shaft machine according to the first aspect of the invention; and providing pressurised fluid to the first external fluid access port such that the sealing member moves from an unsealed position to a sealed position to seal the rotary shaft.

[0056] According to a fifth aspect of the invention, there is provided a method of operating a fluid access system to deactivate a first sealing member within the machine, the method comprising the steps of: providing a rotary shaft machine according to the first aspect of the invention; and evacuating pressurised fluid to the first external fluid access port such that the sealing member moves from a sealed position to an unsealed position to unseal the rotary shaft.

[0057] BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The prior art and embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0059] Fig. 1 shows a cross-sectional view of a prior art industrial system comprising an electric motor and a compressor;

[0060] Fig. 2 shows part of a high-temperature heat pump system comprising an electric motor and a compressor; and

[0061] Fig. 3 shows a detailed view of a section through part of the heat pump system of Fig. 1 .

[0062] DETAILED DESCRIPTION

[0063] Figure 1 shows part of a prior art system 1 . The system 1 comprises a compressor 2, an intermediate section 3 and an electric motor 4.

[0064] The compressor 2 comprises a cast compressor block 21 for containing the other components of the compressor 2 (not shown) and providing a reservoir for lubricating fluid (not shown). The compressor 2 utilises a rotating shaft 22 in normal operation. Further details of this utilisation are omitted here in the interest of brevity as they will be easily known by a person skilled in the art. It will be understood that the rotating shaft may be provided for a myriad of purposes in various different machines in the prior art. The intermediate section 3 comprises an intermediate section housing 31 which comprises a front access hatch 32 and a rear access hatch 32’. The electric motor 4 is configured to drive the rotating shaft 22 in use.

[0065] It will be easily understood that the system 1 is generally speaking substantially tubular in construction. The compressor 2 is connected to the intermediate housing 3 which connects to the electric motor 4.

[0066] Attached to the compressor block 21 there is an expandable seal 24 comprising an aperture through which the compressor rotatable shaft 22 passes through in use. The expandable seal 24 is configured to be selectively expanded to provide sealing around the compressor rotatable shaft 22. It will be understood by a person skilled in the art that the prior art example shown in Figure 1 only comprises one expandable seal, however it is common for multiple expandable seals to be used to seal a rotatable shaft 22. In this connection, there may be a plurality of stationary and / or rotary shaft seals in some prior art examples. Regardless of the number of stationary and / or rotary shaft seals provided in any prior art example, the expandable seals 24 require a fluid connection such that they can be activated or deactivated when required. In this connection, the expandable seal 24 is provided with first and second fluid communication ports 24A, 24B such that hydraulic fluid can be provided or removed from the expandable seal 24 in use. It will be understood that there are many expandable seals in the prior art whereby a liquid or gas is required to be provided or removed from the seal 24 in use to activate or deactivate the seal 24.

[0067] The first and second fluid communication ports 24A, 24B are provided on the expandable seal 24. To access the fluid communication ports 24A, 24B, either or both access hatches 32, 32’ can be removed (as shown in Figure 1 for the front access hatch 32). Although not shown in Figure 1 , in some prior art examples there may be a myriad of other equipment within the intermediate housing 3 such that access to the first and second fluid communication ports 24A, 24B is difficult and / or time consuming. Additionally, in some prior art examples the first and second fluid communication ports 24A, 24B may be communicated with via fluid communication hoses (not shown). During operation of the expandable seal 24 or during servicing, repair or maintenance, the first and / or second fluid communication ports 24A, 24B may need to be accessed at any time.

[0068] In this connection, a technician may remove one or both of the first access hatch 32 or the second access hatch 32’ and then connect fluid communication lines to the first and / or second fluid communication ports 24A, 24B or locate the fluid communication hoses. If fluid communication hoses are provided, the hoses can easily become tangled with each other or with other equipment (not shown) within the intermediate section 3.

[0069] Figure 2 shows part of a high-temperature heat pump system 100. The system 100 comprises a compressor 200, an intermediate section 300 and an electric motor 400.

[0070] The compressor 200 utilises a rotating shaft (not shown in Figure 2) in normal operation. Further details of this utilisation are omitted here in the interest of brevity as they will be easily known by a person skilled in the art. Furthermore, it is not relevant the purpose of the rotating shaft in the particular example disclosed herein. It will be understood that the rotating shaft may be provided for a myriad of purposes in various different machines. The compressor 200 comprises a compressor block 210 which in the presently described example is a cast housing for containing the other components of the compressor 200 and providing a reservoir for lubricating fluid, as will be explained in more detail later. The compressor block 210 comprises a front connection panel 211 comprising a front first port 212 and a front second port 213.

[0071] The intermediate section 300 comprises an intermediate section housing 310 which comprises a front access hatch 320. The electric motor 400 is configured to provide a rotating shaft (not shown in Figure 2) in use.

[0072] A detailed section view of part of the compressor 200 and intermediate section 300 through section line A-A on Figure 2 is shown in Figure 3. The section view is a top down section view, looking from the top of the heat pump system 100 downwards. In this connection, features at the rear of the heat pump system 100 that cannot be seen in Figure 2 can now be seen in Figure 3. It will be easily understood that the heat pump system 100 is generally speaking substantially tubular in construction, and that the front side which is visible in Figure 2 is similar to the rear side which cannot be seen in Figure 2. In this connection, as described above, the front connection panel 211 comprising the front first port 212 and front second port 213 can be seen in Figure 3 along with the front access hatch 320 and a rear connection panel 21 T comprising a rear first port 212’ and rear second port 213’ along with a rear access hatch 320’. Referring to Figure 2, it can be seen that the compressor 200, intermediate housing 300 and electric motor 400 are modular, in that each of these main components can be removed from the heat pump system 100 and replaced. In this connection, the compressor 200 connects to the intermediate housing 300 which connects to the electric motor 400. Referring to Figure 3, an electric motor rotatable shaft 410 is provided from the electric motor 400. However, due to the modular nature of the electric motor 400 and compressor 200, the electric motor rotatable shaft 410 is connected to a compressor rotatable shaft 220 through a coupling 330 provided to operatively connect the two rotatable shafts 410, 220 such that rotation of the electric motor rotatable shaft 410 causes rotation of the compressor rotatable shaft 220. In some examples the coupling 330 may be provided as a claw coupling or a disc coupling or jaw coupling. The coupling 330 may in some examples comprise a gearing arrangement and / or a clutch arrangement.

[0073] Referring now to further details of the compressor 200 shown in Figure 3, the compressor 200 comprises a lubricant reservoir 230 comprising lubricant (not shown) to lubricate various internal components of the compressor 200. The lubricant reservoir 230 is typically pressurised above atmospheric pressure both during operation and during maintenance. Typically, the lubricant reservoir 230 is only not pressurised above atmospheric pressure when the lubricant reservoir is being filled initially, in which case it is evacuated to a low vacuum. Attached to the compressor block 210 there is an end cap 240 comprising an aperture 241 through which the compressor rotatable shaft 220 passes through in use. The end cap 240 comprises a circular expandable seal 242 which is configured to be selectively expanded to provide sealing around the compressor rotatable shaft 220. That is to say, the expandable seal 242 can be selectively moved from an open position in which the expandable seal 242 does not contact and seal the rotatable shaft 220 to a closed position in which the expandable seal 242 does contact and seal against the rotatable shaft 220. In this regard, the expandable seal 242 can be used as a service seal. That is to say, the expandable seal 242 is put into the open position when the rotatable shaft 220 is rotating in normal operation of the compressor 200 and sealing of the shaft 220 is provided by a cartridge seal 250. The expandable seal 242 is put into the closed position when the rotatable shaft 220 is not rotating and the cartridge seal 250 is not sealing the shaft 220. In this way, the expandable seal 242 can be used to provide sealing of the shaft 220 when the cartridge seal 250 is to be maintained or removed and replaced. By providing a means of sealing the shaft 220 and lubricant reservoir 230, the lubricant in the lubricant reservoir 230 need not be drained of lubricant when the cartridge seal 250 is to be maintained.

[0074] In the presently described example, the expandable seal 242 is in the form of a hydraulically activated expandable seal. There is a first expandable seal fluid communication channel 243 provided in the end cap 240 to provide hydraulic fluid to the expandable seal 242 when required. Further details of the first expandable seal fluid communication channel 243 will be discussed later.

[0075] The end cap 240 is configured to close an aperture in the lubricant reservoir 230, and provide sealing of the lubricant reservoir 230 where the end cap 240 engages the compressor block 210. In this connection, it will be understood that the end cap 240 and / or compressor block 210 may be provided with sealing features such as, but not limited to, gaskets and o-rings to ensure that the lubricant does not leak from the lubricant reservoir 230. The aperture which is closed by the end cap 240 is relatively large, in that it may be usefully used as an access point to assemble components in the interior of the compressor 200 during assembly of the compressor 200.

[0076] Still referring to Figure 3, the cartridge seal 250 in the presently described example is in the form of a low-friction rotary shaft seal, provided with a plurality of shaft sealing elements, namely first 250A, second 250B, third 250C and fourth 250D shaft sealing elements. The first 250A, second 250B and fourth 250D shaft sealing elements are provided in a first orientation with a lip feature pointing away from the lubricant reservoir 230. The third shaft sealing element 250C is provided in a second orientation with a lip feature pointing towards the lubricant reservoir 230. As previously explained, the lubricant reservoir 230 is typically evacuated of air when it is initially filled with lubricant. The fourth shaft sealing element 250D is provided in the first orientation such that it will prevent air from leaking into the lubricant reservoir 230 when the lubricant reservoir 230 is drawn down to below atmospheric pressure. Between the second and third shaft sealing elements 250B, 250C there is a barrier fluid chamber 251. The barrier fluid chamber 251 is the volume within the cartridge seal 250 which can be pressurised and depressurised to activate the cartridge seal 250 in use. In this connection, to operate the cartridge seal 250 to provide sealing of the shaft 220, the barrier fluid chamber 251 is pressurised to a pressure greater than the pressure in the lubricant reservoir 230. The third seal 250C ensures that the barrier fluid does not leak out into the intermediate section 300. The first and second seals 250A, 250B provide sealing of the lubricant reservoir 230 by the higher pressure within the barrier fluid chamber 251 maintaining the seals 250A, 250B in a sealing position. In use a very thin film of barrier fluid gathers between the sealing elements 250A, 250B, 250C, 250D and the shaft 220, such that a very low friction seal is provided by the cartridge seal 250. In this connection, the sealing elements 250A, 250B, 250C, 250D will provide a long service life.

[0077] The cartridge seal 250 can be used to provide sealing of the rotatable shaft 220 when the rotatable shaft 220 is rotating in use. It is common for such industrial sealing systems as the cartridge seal 250 to be maintained or replaced at particular service intervals. Although the cartridge seal 250 of the presently described example provides a longer service life, it may still need to be maintained or replaced. Furthermore, in other examples utilising seals with higher friction, the seals may need to be maintained more often than in the presently described example. In this connection, the rotatable shaft 220 may need to be stopped from rotating such that the cartridge seal 250 can be maintained or replaced. As explained above, when the cartridge seal 250 is to be maintained, the expandable seal 242 is moved to the closed position such that a fluid-tight seal is formed around the shaft 220 which is not rotating. In this way the lubricant in the lubricant reservoir 230 is maintained within the reservoir 230 while the cartridge seal 250 is being maintained or replaced. The cartridge seal 250 is provided with a first fluid injection channel 252, a first fluid ejection channel 253 and a first bi-directional fluid communication channel 254. The first fluid injection channel 252 is for pressurising the barrier fluid reservoir 251 . The first fluid ejection channel 253 is for de-pressurising the barrier fluid reservoir 251 . The first bi-directional fluid communication channel 254 is for pressurising or depressurising the barrier fluid reservoir 251 .

[0078] The first fluid injection channel 252, first fluid ejection channel 253 and first bi-directional fluid communication channel 254 are each provided internally in the cartridge seal 250 and connect the barrier fluid chamber 251 to a point on the cartridge seal 250 adjacent the end cap 240.

[0079] The end cap 240 is provided with a second fluid injection channel 252’, a second fluid ejection channel 253’ and a second bi-directional fluid communication channel 254’, which are arranged internally in the end cap 240 and connect the first fluid injection channel 252, first fluid ejection channel 253 and first bi-directional fluid communication channel 254 to channels in the compressor block 210 as will now be explained.

[0080] The compressor block 210 is provided with a third fluid injection channel 252”, a third fluid ejection channel 253” and a third bi-directional fluid communication channel 254”, which are arranged internally in the compressor block 210 and connect the second fluid injection channel 252’, second fluid ejection channel 253’ and second bi-directional fluid communication channel 254’ to the rear first port 212’, the rear second port 213’ and the front second port 213, respectively. Still referring to Figure 3, further details of the activation and deactivation of the expandable seal 242 is now provided. As previously explained, there is provided a first expandable seal fluid communication channel 243 provided in the end cap 240 to provide hydraulic fluid to the expandable seal 242 when required. Similarly, there is a second expandable seal fluid communication channel 243” arranged internally in the compressor block 210 to connect the first expandable seal fluid communication channel 243 to the front first port 212.

[0081] The front connection panel 211 and rear connection panel 21 T provided with the front first port 212, rear first port 212’ and front second port 213, rear second port 213’, respectively, are located on the external surface of the compressor block 210 such that the fluid ports 212, 212’, 213, 213’ can be easily accessed when required.

[0082] In this connection, when it is desired to activate the cartridge seal 250, a connection may be made to the rear first port 212’ and when it is desired to deactivate the cartridge seal 250, a connection may be made to the rear second port 213’. Alternatively, the cartridge seal 250 may be activated and deactivated by connection being made to the front second port 213.

[0083] Therefore, to activate and deactivate the cartridge seal 250, it is not required to open the front 320 or rear 320’ access hatch to gain access to the internal volume of the intermediate section 300. Furthermore, it is not required to make a connection directly onto the cartridge seal 250 from the internal volume of the intermediate section 300. In some machines, such as the high temperature heat pump system 100 shown in the present example, it may be required that the front 320 and / or rear 320’ access hatches are opened anyway during servicing and maintenance, to provide access to other components in the heat pump system 100. In this connection, when the hatches 320, 320’ are to be opened anyway, the advantage provided is that direct connection onto the cartridge seal 250 is not required, which may make activation and / or deactivation of the cartridge seal 250 easier and faster.

[0084] Similarly, when it is desired to activate or deactivate the expandable seal 242, a connection may be made to the front first port 212. Therefore, to activate and deactivate the expandable seal 242, it is not required to open the front 320 or rear 320’ access hatch to gain access to the internal volume of the intermediate section 300. Furthermore, it is not required to make a connection directly onto the expandable seal 242 from the internal volume of the intermediate section 300.

[0085] The front first port 212, rear first port 212’, front second port 213 and rear second port 213’ may be provided with adaptors or connectors such that fluid communication lines may be easily connected to the ports 212, 212’, 213, 213’ as required. Furthermore, each port 212, 212’, 213, 213’ may be provided with any appropriate sealing means such that hydraulic fluid within the fluid communication channels 252, 252’, 252”, 253, 253’, 253”, 254, 254’, 254”, 243, 243” does not leak when the fluid communication lines are removed from the ports 212, 212’, 213, 213’. In some examples, the sealing means may be a stab connector, a screw fitting, or any other suitable connection.

[0086] It will be understood that at all points in the system where two fluid communication channels meet, there may be appropriate sealing elements such as gaskets, washers, o-rings or other intermediate seals which will be apparent without further explanation here.

[0087] The heat pump system 100 in the presently described example is a high temperature heat pump system. However, it will be understood that the disclosure is not limited to heat pump systems.

[0088] It will be understood that at the time of writing, the term “high-temperature heat pump” generally refers to the heat pumps capable of supplying output temperatures above 55 degrees Celsius. It will be appreciated by a person skilled in the art that the definition of “high-temperature” in this context may change over time, and it is foreseeable with advancements in technology that in the future “high-temperature” may be used to refer to heat pumps with an output temperature of above 80 degrees Celsius for example, or even higher.

[0089] In the presently described example, the compressor block 210 is sealed by an end cap 240 and a cartridge seal 250. It will be understood that in some examples only an end cap 240 may be provided. In other examples, only a cartridge seal 250 may be provided. Regardless of the presence of other components in the system 100, the activation or deactivation of an internally located component in the system 100 may be made easier by internal routing of the fluid communication channel used for activation or deactivation. In this connection, regardless of the purpose of the component located internally in the system, and regardless of the location where it is provided in use, the activation channel for the component may be routed through another component of the system such that access to a port to activate or deactivate the component may be made simpler and faster.

[0090] In the above description there are several features of the described examples that are well-known to a person skilled in the art, and which have either been omitted or at least not described in detail for the sake of brevity.

[0091] The skilled person would understand that throughout the entire disclosure, the terms fluid access channel and fluid communication channel are interchangeable. The skilled person would understand that where the term fluid access channel is used it may be understood as either fluid access channel or fluid communication channel and where the term fluid communication channel is used it may be understood as fluid communication channel or fluid access channel.

Claims

CLAIMS1 . A rotary shaft machine (100) comprising a fluid access system for providing activation and / or deactivation of a first sealing member (250A, 250B, 250C, 250D) within the machine (100), the machine comprising: a machine housing (210) comprising: a first housing fluid access channel (254”) within the machine housing (210); and a first external fluid access port (213) configured to provide fluid communication from outside of the machine housing (210) to the first housing fluid access channel (254”); a first fluid-activatable sealing component (250) in fluid communication with the first housing fluid access channel (254”) and comprising at least a first sealing member (250A, 250B, 250C, 250D) movable between an unsealed position and a sealed position; and a rotary shaft (220) arranged to pass from outside of the machine housing (210) to inside of the machine housing (210) through the fluid- activatable sealing component (250); wherein in the unsealed position the first sealing member (250A, 250B, 250C, 250D) does not seal around the rotary shaft (220) and in the sealed position the first sealing member (250A, 250B, 250C, 250D) forms a fluid tight seal with the rotary shaft (220); such that the first sealing member (250A, 250B, 250C, 250D) can be moved to seal around the rotary shaft (220) and / or to break sealingaround the rotary shaft (220) by providing or evacuating fluid to or from the first external fluid access port (213) on the machine housing (210).

2. The rotary shaft machine (100) according to claim 1 , wherein the first fluid- activatable sealing component (250) further comprises a first sealing member fluid communication channel (254) configured to provide fluid communication between the first housing fluid access channel (254”) and the first sealing member (250A, 250B, 250C, 250D).

3. The rotary shaft machine (100) according to claim 1 or 2, wherein the first external fluid access port (213) is configured to receive positive and negative pressure such that the first sealing member (250A, 250B, 250C, 250D) can be activated and deactivated.

4. The rotary shaft machine (100) according to any preceding claim, wherein the machine housing (210) further comprises: a second housing fluid access channel (252”) within the machine housing (210) and in fluid communication with the first fluid-activatable sealing component (250); and a second external fluid access port (212’) configured to provide fluid communication from outside of the machine housing (210) to the second housing fluid access channel (252”); such that the first sealing member (250A, 250B, 250C, 250D) can bemoved to seal around the rotary shaft (220) by providing fluid to the second external fluid access port (212’) on the machine housing (210).

5. The rotary shaft machine (100) according to claim 4, wherein the first fluid- activatable sealing component (250) further comprises a second sealing member fluid communication channel (252) configured to provide fluid communication between the second housing fluid access channel (252”) and the first sealing member (250A, 250B, 250C, 250D).

6. The rotary shaft machine (100) according to claim 4 or 5, wherein the second external fluid access port (212’) is configured to receive positive pressure such that the first sealing member (250A, 250B, 250C, 250D) can be activated.

7. The rotary shaft machine (100) according to any preceding claim, wherein the machine housing (210) further comprises: a third housing fluid access channel (253”) within the machine housing (210) and in fluid communication with the first fluid-activatable sealing component (250); and a third external fluid access port (213’) configured to provide fluid communication from outside of the machine housing (210) to the third housing fluid access channel (253”); such that the first sealing member (250A, 250B, 250C, 250D) can bemoved to break sealing around the rotary shaft (220) by evacuating fluid from the third external fluid access port (213’) on the machine housing (210).

8. The rotary shaft machine (100) according to claim 7, wherein the first fluid- activatable sealing component (250) further comprises a third sealing member fluid communication channel (253) configured to provide fluid communication between the third housing fluid access channel (253”) and the first sealing member (250A, 250B, 250C, 250D).

9. The rotary shaft machine (100) according to claim 7 or 8, wherein the third external fluid access port (213’) is configured to receive negative pressure such that the first sealing member (250A, 250B, 250C, 250D) can be deactivated.

10. The rotary shaft machine (100) according to any preceding claim, further comprising a second sealing component (240) configured to seal the machine housing (210), wherein the second sealing component (240) is located between the machine housing (210) and the first activatable sealing component (250), and the rotary shaft (220) is arranged to pass from outside of the machine housing (210) to inside of the machine housing (210) through the second sealing component (240).11 . The rotary shaft machine according to claim 10, wherein the second sealing component (240) further comprises a first connecting fluid communication channel (254’) fluidly connecting the first housing fluid access channel (254”) with the first activatable sealing component (250).

12. The rotary shaft machine (100) according to claim 10 when dependent on: claim 2; or any of claims 3 to 9 when dependent on claim 2, wherein the second sealing component (240) further comprises a first connecting fluid communication channel (254’) fluidly connecting the first housing fluid access channel (254”) with the first sealing member fluid communication channel (254).

13. The rotary shaft machine (100) according to claim 10 when dependent on: claim 4; or any of claims 6 or 7 to 9 when dependent on claim 4; wherein the second sealing component (240) further comprises a second connecting fluid communication channel (252’) fluidly connecting the second housing fluid access channel (252”) with the first activatable sealing component (250).

14. The rotary shaft machine (100) according to claim 10 when dependent on:claim 5; or any of claims 6 to 9 when dependent on claim 5, wherein the second sealing component (240) further comprises a second connecting fluid communication channel (252’) fluidly connecting the second housing fluid access channel (252”) with the second sealing member fluid communication channel (252).

15. The rotary shaft machine (100) according to claim 10 when dependent on: claim 7; or claim 9 when dependent on claim 7, wherein the second sealing component (240) further comprises a third connecting fluid communication channel (253’) fluidly connecting the third housing fluid access channel (253”) with the first activatable sealing component (250).

16. The rotary shaft machine (100) according to claim 10 when dependent on: claim 8; or claim 9 when dependent on claim 8, wherein the second sealing component (240) further comprises a third connecting fluid communication channel (253’) fluidly connecting the third housing fluid access channel (253”) with the third sealing member fluid communication channel (253).

17. The rotary shaft machine (100) according to any of claims 10 to 16, further configured for providing activation and / or deactivation of a second sealing member (242) within the machine, the machine further comprising: a fourth housing fluid access channel (243”) within the machine housing (210); and a fourth external fluid access port (212) configured to provide fluid communication from outside of the machine housing (210) to the fourth housing fluid access channel (243”); wherein the second sealing component (240) further comprises a second fluid-activatable sealing component (240) in fluid communication with the fourth housing fluid access channel (243”) and comprising at least a second sealing member (242) movable between an unsealed position and a sealed position; wherein the rotary shaft (220) is arranged to pass from outside of the machine housing (210) to inside of the machine housing (210) through the second activatable sealing component (240); wherein in the unsealed position the second sealing member (242) does not seal around the rotary shaft (220) and in the sealed position thesecond sealing member (242) forms a fluid tight seal with the rotary shaft (220); such that the second sealing member (242) can be moved to seal around the rotary shaft (220) and / or to break sealing around the rotary shaft (220) by providing or evacuating fluid to or from the fourth external fluid accessport (212) on the machine housing (210).

18. The rotary shaft machine (100) according to claim 17, wherein the second fluid-activatable sealing component (240) further comprises a fourth sealing member fluid communication channel (243) configured to provide fluid communication between the fourth housing fluid access channel (243”) and the second sealing member (242).

19. The rotary shaft machine (100) according to claim 17 or 18, wherein the fourth external fluid access port (212) is configured to receive positive and negative pressure such that the second sealing member (242) can be activated and deactivated.

20. The rotary shaft machine (100) any of claim 17 to 19, wherein the machine housing (210) further comprises: a fifth housing fluid access channel within the machine housing (210) and in fluid communication with the second fluid- activatable sealing component (240); and a fifth external fluid access port configured to provide fluid communication from outside of the machine housing (210) to the fifth housing fluid access channel; such that the second sealing member (242) can be moved to seal around the rotary shaft (220) by providing fluid to the fifth external fluid accessport on the machine housing (210).21 . The rotary shaft machine (100) according to claim 20, wherein the second fluid-activatable sealing component (240) further comprises a fifth sealing member fluid communication channel configured to provide fluid communication between the fifth housing fluid access channel and the second sealing member (242).

22. The rotary shaft machine (100) according to claim 20 or 21 , wherein the fifth external fluid access port is configured to receive positive pressure such that the second sealing member (242) can be activated.

23. The rotary shaft machine (100) according to any of claims 17 to 22, wherein the machine housing (210) further comprises: a sixth housing fluid access channel within the machine housing (210) and in fluid communication with the second fluid- activatable sealing component (240); and a sixth external fluid access port configured to provide fluid communication from outside of the machine housing (210) to the sixth housing fluid access channel; such that the second sealing member (242) can be moved to break sealing around the rotary shaft (220) by evacuating fluid from the sixth external fluid access port on the machine housing (210).

24. The rotary shaft machine (100) according to claim 23, wherein the second fluid-activatable sealing component (240) further comprises a sixth sealing member fluid communication channel configured to provide fluid communication between the sixth housing fluid access channel and the second sealing member.

25. The rotary shaft machine (100) according to claim 24, wherein the sixth external fluid access port is configured to receive negative pressure such that the second sealing member (242) can be deactivated.

26. The rotary shaft machine (100) according to any preceding claim, wherein the first fluid-activatable sealing component (250) is configured to provide sealing of a rotating shaft in use.

27. The rotary shaft machine (100) according to claim 10 or any of claims 11 to 26 when dependent on claim 10, wherein the second fluid-activatable sealing component (240) is configured to provide sealing of a stationary shaft in use.

28. The rotary shaft machine (100) according to any preceding claim, wherein the machine housing (210) is a compressor block configured to be substantially filled with lubricant in use.

29. A kit for assembling a rotary shaft machine (100) comprising a fluid access system for providing activation and / or deactivation of a first sealing member (250A, 250B, 250C, 250D) within the machine, the kit comprising: a machine housing (210) comprising: a first housing fluid access channel (254”) within the machine housing (210); and a first external fluid access port (213) configured to provide fluid communication from outside of the machine housing (210) to the first housing fluid access channel (254”); a first fluid-activatable sealing component (250) configured to be in fluid communication with the first fluid access channel (254”) in use and comprising at least a first sealing member (250A, 250B, 250C, 250D) movable between an unsealed position and a sealed position; and a rotary shaft (220) configured to pass from outside of the machine housing (210) to inside of the machine housing (210) through the first fluid-activatable sealing component (250) in use; wherein when assembled, in the unsealed position the first sealing member (250A, 250B, 250C, 250D) does not seal the rotary shaft (220) and in the sealed position and first sealing member (250A, 250B, 250C, 250D) forms a fluid tight seal with the rotary shaft (220);such that the first sealing member (250A, 250B, 250C, 250D) can be moved in use to seal around the rotary shaft (220) and / or to break sealing around the rotary shaft (220) by providing or evacuating fluid to or from the first external fluid access port (213) on the machine housing (210).

30. The kit according to claim 29, further comprising a second sealing component (240) configured to seal the machine housing (210) wherein the second sealing component (240) is configured to be located in use between the machine housing (210) and the first activatable sealing component (250), and the second sealing component (240) is configured such that the rotary shaft (220) can pass from outside of the machine housing (210) to inside of the machine housing (210) through the second sealing component (240) in use.

31. The kit according to claim 30, wherein the second sealing component (240) further comprises a first connecting fluid communication channel (254’) configured to fluidly connect the first housing fluid access channel (254”) with the first activatable sealing component (250) when the kit is assembled.

32. A method of assembling a rotary shaft machine (100) comprising a fluid access system for providing activation and / or deactivation of a first sealingmember (250A, 250B, 250C, 250D) within the machine (100), the method comprising the steps of: providing a machine housing (210) comprising: a first housing fluid access channel (254”) within the machine housing (210); and a first external fluid access port (213) configured to provide fluid communication from outside of the machine housing (210) to the first housing fluid access channel (254”); providing a first fluid-activatable sealing component (250) comprising at least a first sealing member (250A, 250B, 250C, 250D) movable between an unsealed position and a sealed position; providing a rotary shaft (220); arranging the first fluid-activatable sealing component (250) in fluid communication with the first housing fluid access channel (254”); and arranging the rotary shaft (220) to pass from outside of the machine housing (210) to inside of the machine housing (210) through the fluid-activatable sealing component (250) such that in the unsealed position the first sealing member (250A, 250B, 250C, 250D) does not seal the rotary shaft (220) and in the sealed position and firstsealing member (250A, 250B, 250C, 250D) forms a fluid tight seal with the rotary shaft (220); such that when fluid is provided or evacuated from the first external fluid access port (213) on the machine housing (210), the first sealing member (250A, 250B, 250C, 250D) is moved to seal around the rotary shaft (220) and / or break sealing around the rotary shaft (220).

33. A method of operating a fluid access system to activate a first sealing member (250A, 250B, 250C, 250D) within the machine (100), the method comprising the steps of: providing a rotary shaft machine (100) according to claim 1 ; and providing pressurised fluid to the first external fluid access port (213) such that the sealing member (250A, 250B, 250C, 250D) moves from an unsealed position to a sealed position to seal the rotary shaft (220).

34. A method of operating a fluid access system to deactivate a first sealing member (250A, 250B, 250C, 250D) within the machine (100), the method comprising the steps of: providing a rotary shaft machine (100) according to claim 1 ; and evacuating pressurised fluid to the first external fluid access port (213) such that the sealing member (250A, 250B, 250C, 250D) moves from a sealed position to an unsealed position to unseal therotary shaft (220).

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