Sewage Treatment Machine

Abstract

The wastewater treatment machine (1) comprises a closed vessel (2) in which the liquid to be treated is boiled, a vacuum generator (3) configured to maintain the interior of the closed vessel (2) at a given pressure having a value less than the ambient / external pressure, and a heat pump assembly (5) associated with the closed vessel (2) so as to transfer heat to the liquid present at the bottom of the closed vessel (2), thereby boiling the liquid, and at the same time remove heat from the vapor reaching the top of the closed vessel (2), thereby condensing the vapor and obtaining a distilled liquid, the heat pump assembly (5) containing a refrigerant fluid comprising one or more gases of the hydrofluoroolefin family at a percentage greater than 3%.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from Italian Patent Application No. 102019000022839, filed December 3, 2019, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a wastewater treatment machine.

[0003] More particularly, the invention relates to vacuum evaporators for the treatment of aqueous liquids.Explicit reference is made to the following disclosure for the use of the present invention, without loss of generality. [Background technology]

[0004] As is known, a vacuum evaporator is a machine capable of concentrating, by means of evaporation at less than atmospheric pressure, the contaminants present in the wastewater which it receives at its inlet, providing at its outlet two different streams of liquid, one with a low concentration of contaminants and the other with a high concentration of contaminants.

[0005] The liquid stream having a low concentration of contaminants is substantially free of contaminants and can be reused in the production process or freely released into the environment.

[0006] Liquids with high concentrations of contaminants are generally further collected and treated in special waste plants.

[0007] The most common vacuum evaporators on the market are provided with a large enclosed vessel maintained at a pressure of less than 0.9 bar and utilize a heat pump circuit to boil the liquid present inside the vessel at a low temperature and condense the resulting vapor in order to concentrate the contaminants in the portion of the liquid remaining at the bottom of the vessel.

[0008] CN109701291A, Japanese Patent No. 0852461, and US Patent Application Publication No. 2012 / 055777(A1) disclose vacuum evaporators of this type.

[0009] Unfortunately, current vacuum evaporator heat pump circuits use hydrofluorocarbons (e.g. R-134a gas) as refrigerant gases, which are non-toxic and have no impact on the ozone layer, but have very high GWP (acronym for Global Warming Potential) values ​​associated with environmental problems. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] CN109701291A [Patent Document 2] Japanese Patent No. 0852461 [Patent Document 3] US Patent Application Publication No. 2012 / 055777(A1) Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a vacuum evaporator for the treatment of aqueous liquids which has a lower environmental impact than currently known vacuum evaporators and at the same time is more efficient. [Means for solving the problem]

[0012] In accordance with these objects, according to the present invention there is provided a sewage treatment machine as defined in claim 1 and preferably, but not necessarily, as defined in any of the claims dependent thereon.

[0013] The present invention will now be described with reference to the accompanying drawings, which show non-limiting examples of embodiments thereof. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view, with parts removed for clarity, of a wastewater treatment machine implemented in accordance with the teachings of the present invention; [Diagram 2]FIG. 2 is a schematic diagram of the sewage treatment machine shown in FIG. 1 with parts removed for clarity. [Diagram 3] FIG. 2 is a schematic diagram of a variant of the embodiment of the wastewater treatment machine shown in the previous figure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] With reference to Figures 1 and 2, the number 1 indicates as a whole a sewage treatment machine which may be advantageously used for the treatment of aqueous liquids.

[0016] More specifically, the wastewater treatment machine 1 is configured to receive at an inlet a flow of wastewater to be treated f1 and is specifically configured to concentrate contaminants present in the wastewater at the inlet using evaporation at less than atmospheric pressure, whilst providing at an outlet a distilled liquid flow f2 and a waste liquid flow f3.

[0017] The distilled liquid is substantially free of contaminants or has a low concentration of contaminants and can be reused in the production process or can be freely released into the environment, whereas the waste liquid has a high concentration of contaminants and is suitable to be recovered for subsequent treatment in treatment plants of known types.

[0018] With reference to Figures 1 and 2, the wastewater treatment machine 1 initially comprises a closed reactor or vessel 2, conventionally called evaporation chamber, in which the liquid to be treated, i.e. wastewater, is boiled, preferably having a volume ranging between 100 liters and 7000 liters, and a vacuum generating device 3, preferably operated electrically, configured to maintain the internal volume of the reactor / vessel 2 at a given pressure having a value less than the environmental / external pressure.

[0019] More specifically, the vessel 2 is preferably oblong in shape, is preferably positioned in a substantially vertical position and is preferably configured to be only partially filled with liquid such that the liquid to be treated collects / occupies only the bottom of the vessel 2.

[0020] In the illustrated example, specifically, the container 2 preferably consists of a large watertight closed vessel, preferably made from a metallic material and preferably of substantially cylindrical shape.

[0021] Preferably, the bottom end of the container 2, or even the bottom end of the watertight closed vessel, is generally frusto-conical in shape.

[0022] Meanwhile, the vacuum generator 3 is preferably configured to continuously maintain the pressure inside the vessel / reactor 2 at a value below 0.8 bar, optionally below 0.6 bar.

[0023] More specifically, in the example shown, the pressure inside the vessel / reactor 2 is preferably maintained at a value in the range of 3 kPA to 8 kPA (kilopascals).

[0024] With reference to Figures 1 and 2, the wastewater treatment machine 1 further comprises a supply pipe 4 for the liquid to be treated, configured to lead the liquid to be treated, i.e. wastewater, to the reactor / vessel 2.

[0025] In other words, the supply pipe 4 is configured to conduct the wastewater flow f1 at the inlet of the vessel 2.

[0026] Preferably, the supply line 4 is further constructed such that it is possible to control / vary the flow rate of the liquid stream directed towards the vessel 2. More specifically, the supply line 4 is preferably configured to control / vary the flow rate of the liquid to be treated entering the vessel 2 so as to continuously maintain the liquid height inside the vessel 2 around a given value.

[0027] 1 and 2, the wastewater treatment machine 1 further comprises a heat pump evaporator / condenser assembly 5 connected / associated with the vessel / reactor 2 so as to transfer heat to the liquid present at the bottom of the vessel 2, thereby boiling the liquid, and at the same time removing heat from the vapor reaching the top of the vessel 2, thereby quickly condensing the vapor to obtain a distilled liquid.

[0028] The sewage treatment machine 1 is also provided with a first drain pipe 6 branching off / leaving from the bottom of the container 2 and configured to guide / transport liquid accumulating / stagnating at the bottom of the container 2 to the outside of the container / reactor 2, and a second drain pipe 7 branching off / leaving from the upper part of the container 2 and configured to guide / transport steam formed inside the container 2 and accumulating at the top of the container 2 and / or distilled liquid resulting from condensation of the steam to the outside of the container / reactor 2.

[0029] More specifically, drain line 6 preferably branches off / leaves from the bottom of vessel 2 and drain line 7 preferably branches off / leaves from the top of vessel 2 .

[0030] Specifically, the liquid flowing along drain line 6 has a higher concentration of contaminants, and the condensed vapor or liquid flowing along drain line 7 has a lower concentration of contaminants.

[0031] Thus, the waste liquid flow f3 is led / conveyed outside the treatment machine 1 by the drain line 6, while the distilled liquid flow f2 is led / conveyed outside the treatment machine 1 by the drain line 7.

[0032] 1, the sewage treatment machine 1 is preferably additionally provided with a rigid supporting framework 8, preferably made of a metal material and configured to be stably placed on the ground and optionally anchored thereto. The vessel 2, the vacuum generating device 3, the supply pipe 4, the heat pump evaporator / condenser assembly 5 and the two drain pipes 6 and 7 are preferably stably fixed / arranged on the rigid supporting framework 8 so as to form a single block that can be easily transported.

[0033] In the illustrated example, in particular, the rigid supporting skeletal structure 8 preferably has a cage-like structure and / or is substantially parallelepiped shaped and is preferably formed by metal bars joined and fixed to one another.

[0034] With reference to FIG. 1 , the sewage treatment machine 1 preferably finally comprises an electronic control device 9 for controlling the various components of the vessel 2 and / or the vacuum generating device 3, the various components of the supply pipe 4 and / or the various components of the heat pump evaporator / condenser assembly 5 and / or the various components of the two drain pipes 6 and 7, and which is preferably stably fixed / located on a rigid supporting skeleton structure 8.

[0035] Referring to FIG. 2, in the illustrated example, specifically, the supply piping 4 comprises a pipe 10 connecting the inlet of the treatment machine 1 to the container 2 so as to direct the liquid to be treated, i.e. wastewater, to the inlet of the container 2, and a regulating valve 11 with controlled opening and closing positioned along the pipe 10 and configured to regulate the flow of the liquid directed towards the container 2, and preferably also comprises a filter 12 positioned along the pipe 10, preferably upstream of the regulating valve 11, and configured to block solid particles above a given size.

[0036] More particularly, filter 12 is preferably constructed to retain solid particles having a particle size greater than 800 μm to 1000 μm (microns), or even greater than 500 μm (microns).

[0037] The liquid to be treated is therefore sucked into the container 2 by negative pressure without the use of a feed pump.

[0038] Optionally, the supply pipe 4 additionally comprises a manually operated shut-off valve 13 disposed along the pipe 10 upstream of the control valve 11 and / or the filter 12 .

[0039] Preferably, the supply pipe 4 additionally comprises a level sensor or level switch 14, preferably positioned inside the vessel 2 and configured to detect or switch when the height of the liquid inside the vessel 2 reaches or exceeds a maximum given value.

[0040] The regulator valve 11 is further preferably configured to open and close based on a signal coming from a level sensor or level switch 14 .

[0041] More specifically, the regulating valve 11 is preferably controlled by an electronic control device 9 on the basis of a signal coming from a level sensor or level switch 14 and other operating parameters of the processing machine 1 .

[0042] The drain pipe 6 instead preferably comprises a main pipe 15 which branches / leaves from the bottom of the container 2 and terminates at the first outlet of the treatment machine 1, and a suction pump 16, preferably electrically operated, positioned along the pipe 15 and configured to suck liquid accumulating / stagnating at the bottom of the container 2, i.e. liquid with a high concentration of contaminants, from the container 2 and pump the liquid towards the outlet.

[0043] Specifically, in the illustrated example, suction pump 16 is preferably a centrifugal pump.

[0044] Optionally, the drain line 6 is additionally provided with a manually operated shut-off valve 17 located along the pipe 15 upstream of the circulation pump 16, i.e., between the suction pump 16 and the vessel 2.

[0045] The shut-off valve 17 makes it possible to isolate the vessel 2 so as to allow possible maintenance work to be carried out on the suction pump 16 without providing a vacuum seal for the vessel 2 .

[0046] Preferably, the drain piping 6 additionally comprises a recirculation pipe 18 which branches off from the main pipe 15 downstream of the suction pump 16 and returns to the vessel 2, preferably connecting to the vessel 2 at a given height from the bottom of the vessel 2, and a regulating valve 19 with controlled opening and closing, positioned along the main pipe 15 downstream of the branch of the recirculation pipe 18 and configured to adjust / control the flow of liquid along the end section of the main pipe 15.

[0047] Preferably, the suction pump 16 is additionally configured to circulate the liquid continuously along the closed loop formed by the recirculation pipe 18 and the container 2 .

[0048] Thus, by opening or closing the regulating valve 19 it is possible to direct or not direct the liquid coming from the bottom of the container 2 towards the first outlet of the treatment machine 1 .

[0049] Preferably, the recirculation pipe further connects to the vessel 2 above the free surface of the liquid pooling / stagnating at the bottom of the vessel 2 , i.e. above the maximum height that can be reached by the liquid inside the vessel 2 .

[0050] The drain pipe 6 also comprises a preferably electrically operated, preferably positive displacement, conveying pump 20 located along the end section of the main pipe 15, i.e. downstream of the branch of the recirculation pipe 18 and the control valve 19, if present, and configured to pump the liquid with a high concentration of pollutants coming from the suction pump 16 at a given pressure towards the first outlet of the treatment machine.

[0051] Specifically, in the illustrated example, the delivery pump 20 is a diaphragm pump.

[0052] Optionally, the drain pipe 6 is additionally provided with one or more manually operated shut-off valves 21 positioned along an end section of the main pipe 15 and preferably interposed between the control valve 19 and the conveying pump 20.

[0053] The shut-off valve 21 makes it possible to isolate a single section of the main pipe 15 so as to allow possible maintenance work to be carried out on the control valve 19 and / or the conveying pump 20 without having to provide a vacuum seal on the vessel 2 .

[0054] Preferably, the electronic control device 9 is configured to control the suction pump 16, the regulating valve 19 and the transfer pump 20, if present, based on certain operating parameters of the processing machine 1 and / or based on signals coming from one or more sensors (e.g., a temperature sensor and / or a level sensor) positioned at the bottom of the container 2.

[0055] Referring to FIG. 2, the drain piping 7 preferably further comprises a small tank 24, preferably having a nominal volume in the range between 1 liter and 500 liters and configured to contain the distilled liquid and / or vapor coming from the top of the vessel 2, a first pipe 25 connecting the tank 24 to the top of the vessel / reactor 2, and a second pipe 26 connecting the tank 24 to a second outlet of the processor 1.

[0056] In the illustrated example, specifically, tank 24 is preferably a substantially closed vessel.

[0057] Preferably, the drain pipe 7 further comprises a check valve 27 and / or a non-condensable gas release device 28. The check valve 27 is positioned along the pipe 25 and oriented to prevent the distilled liquid and / or vapor from flowing back towards the vessel 2. The non-condensable gas release device 28 is preferably located at the top of the tank 24 and configured to vent / release the non-condensable gas present in the tank 24 to the outside of the tank 24.

[0058] In the illustrated example, specifically, the non-condensable gas release device 28 is configured to automatically vent / release the non-condensable gas to the outside of the tank 24 .

[0059] Additionally, the drain piping 7 preferably comprises a suction pump 29, preferably electrically operated, configured to suck the distilled liquid from the tank 24 and deliver said liquid at a given pressure to the second outlet of the processor, and a regulating valve 30 with controlled opening and closing, preferably positioned downstream of the suction pump 29, along the pipe 26, configured to adjust / control the flow of the distilled liquid towards the second outlet of the processor.

[0060] Therefore, the distilled liquid is discharged outside the processing machine 1 by operating the suction pump 29 and the control valve 30 simultaneously.

[0061] In particular, in the illustrated example, the suction pump 29 is a centrifugal pump.

[0062] Optionally, the drain line 7 additionally comprises one or more manually operated shut-off valves 31 positioned along the pipe 26 , preferably upstream of the suction pump 29 and downstream of the control valve 30 .

[0063] A shut-off valve 31 makes it possible to isolate the pipe 26 to allow possible maintenance work to be carried out on the suction pump 29 and / or the control valve 30 .

[0064] Preferably, the electronic control device 9 is configured to control the suction pump 29 and the regulating valve 30, if present, based on signals coming from one or more level sensors positioned inside the tank 24, based on one or more flow sensors positioned along the pipe 26, and / or based on certain operating parameters of the processing machine 1.

[0065] Referring to FIG. 2, the vacuum generator 3 is further preferably connected directly to a drain line 7 so as to utilise the distilled liquid produced by the vessel 2 to maintain the vessel 2 at a negative pressure.

[0066] In other words, the vacuum generator 3 uses the distilled liquid and / or vapor produced by the vessel 2 as the working fluid.

[0067] More specifically, in the illustrated example, the vacuum generating device 3 preferably comprises an ejector 34 located just upstream of the tank 24 along the line 25 (i.e., located between the tank 24 and the check valve 27), and a circulation pump 35, preferably electrically operated and preferably of the centrifugal type, located along a recirculation line 36 directly connecting the tank 24 to the ejector 34.

[0068] The circulation pump 35 draws the distilled liquid or vapour from the tank 24 and directs it to the ejector 34, which in turn draws in the distilled liquid and / or vapour present along the tube 25 by means of negative pressure (Venturi effect).

[0069] Optionally, the vacuum generator 3 further comprises one or more manually operated shut-off valves 37 positioned along the recirculation line 36 upstream and / or downstream of the circulation pump 35 .

[0070] A shutoff valve 37 makes it possible to isolate the recirculation line 36 to allow possible maintenance work to be carried out on the circulation pump 35 .

[0071] Preferably, the electronic control device 9 is configured to command the circulation pump 35 based on signals coming from one or more level sensors positioned inside the tank 24, based on signals coming from one or more pressure sensors positioned inside the container 2, and / or based on certain operating parameters of the processing machine 1.

[0072] 1 and 2, on the one hand, a heat pump evaporator / condenser assembly 5 is arranged to heat the liquid stagnating at the bottom of the vessel 2, preferably located along the recirculation pipe 18 of the drain line 6 so as to quickly heat the liquid with a high concentration of contaminants re-entering the vessel 2, and a first heat exchanger 41, conventionally called a high pressure heat exchanger or condenser, arranged to cool / condense the vapor forming the interior of the vessel 2, preferably located along the drain line 6 so as to quickly cool and preferably also at least partially condense the vapor leaving the vessel 2. 7 or at the inlet of the drain line 7, a second heat exchanger 42, conventionally referred to as a low pressure heat exchanger or evaporator, and an expansion valve 43, preferably electronically controlled, interposed between the outlet of the high pressure heat exchanger 41 and the inlet of the low pressure heat exchanger 42, configured to cause a rapid and irreversible expansion of the refrigerant fluid in a gaseous state flowing from the outlet of the heat exchanger 41 towards the inlet of the heat exchanger 42, such that the refrigerant fluid entering the heat exchanger 42 has a pressure and temperature that is appreciably lower than the pressure and temperature of the refrigerant fluid exiting the heat exchanger 41.

[0073] Specifically, the expansion valve 43 may be replaced by a capillary tube or by other active or passive expansion members.

[0074] The heat pump evaporator / condenser assembly 5 further comprises a compressor 44, preferably electrically operated, interposed between the heat exchangers 41 and 42 and configured to compress the refrigerant fluid leaving the heat exchanger 42 and entering / returning to the heat exchanger 41.

[0075] More specifically, a compressor 44, preferably a positive displacement compressor, is interposed between the outlet of the low pressure heat exchanger 42 and the inlet of the high pressure heat exchanger 41 so as to increase the pressure and temperature of the refrigerant fluid directed towards the heat exchanger 41.

[0076] Specifically, in the illustrated example, low pressure heat exchanger 42 is preferably positioned along pipe 25 of drain line 7 immediately downstream of vessel 2 .

[0077] Furthermore, preferably, the low pressure heat exchanger 42 is at least partially housed / inserted inside the vessel 2 at the top of the vessel 2 so as to form the initial section of the drain line 7 .

[0078] Preferably, the heat pump evaporator / condenser assembly 5 further comprises a second low pressure heat exchanger 45, conventionally called an auxiliary evaporator, located inside the tank 24 in the drain line 7 so as to be able to cool the distilled liquid and / or vapour inside the tank 24.

[0079] More specifically, the heat exchanger 45 is preferably connected in parallel with the low pressure heat exchanger 42, and the heat pump evaporator / condenser assembly 5 preferably additionally comprises a second expansion valve 46 or other active or passive expansion member positioned upstream of the inlet of the heat exchanger 45 and configured to cause rapid and irreversible expansion of the gaseous state refrigerant fluid flowing from the outlet of the heat exchanger 41 directed towards the inlet of the heat exchanger 45 such that the refrigerant fluid entering the heat exchanger 45 has a measurably lower pressure and temperature than the refrigerant fluid exiting the heat exchanger 41.

[0080] Specifically, the outlet of the second low pressure heat exchanger 45 is connected to the suction of the compressor 44 .

[0081] Preferably, the electronic control device 9 is configured to command the compressor 44 and, optionally, the expansion valve 43 and, if present, the expansion valve 46 based on certain operating parameters of the processing machine 1 and / or based on signals coming from one or more pressure sensors positioned on the delivery and / or suction side of the compressor 44.

[0082] Alternatively, expansion valve 43 may be controlled by an autonomous mechanical or electronic system, and valve 46, if present, may be an autonomous thermostatic valve.

[0083] Optionally, the evaporator / condenser assembly 5 further comprises an auxiliary heat exchanger 47, preferably integral with fins, positioned immediately downstream of the high pressure heat exchanger 41 and configured to complete the condensation of the refrigerant fluid that transfers excess heat to the external environment.

[0084] In addition to or as an alternative to the auxiliary heat exchanger 47, the evaporator / condenser assembly 5 further includes a second auxiliary heat exchanger 48 positioned immediately upstream of the expansion valve 43 and, if present, immediately upstream of the expansion valve 46, and configured to further cool the gaseous state refrigerant fluid directed towards the expansion valves 43 and 46.

[0085] More specifically, the auxiliary heat exchanger 48 is preferably connected to the external hydraulic circuit so as to be simultaneously passed by the refrigerant fluid coming from the heat exchanger 41 and by the low temperature heat transfer fluid coming from the external hydraulic circuit, thereby removing heat from the refrigerant fluid directed towards the expansion valves 43 and 46.

[0086] Preferably, the circulation of the low temperature heat transfer fluid circulating in the auxiliary heat exchanger 48 may be regulated.

[0087] More specifically, in the illustrated example, the auxiliary heat exchanger 48 is connected to the external hydraulic circuit using a three-way valve 49 that is selectively configured, preferably electrically operated and controlled to switch, to direct the heat transfer fluid to the inlet of the auxiliary heat exchanger 47.

[0088] Preferably, the electronic control device 9 is also configured to control a valve regulating the circulation of the cryogenic heat transfer fluid inside the auxiliary heat exchanger 48, if present.

[0089] The refrigerant fluid contained within the heat pump evaporator / condenser assembly 5 (i.e., the gas that compressor 44 circulates inside heat exchangers 41 and 42, and optionally inside heat exchangers 45 and / or 47) further comprises one or more gases from the family of hydrofluoroolefins, in a percentage greater than 3%.

[0090] Preferably, the hydrofluoroolefin family of gases is the greater amount / percentage component of the refrigerant fluid.

[0091] More particularly, the refrigerant fluid preferably comprises a percentage greater than 30%, optionally greater than 50%, of one or more gases from the family of hydrofluoroolefins.

[0092] Optionally, the refrigerant fluid may contain one or more gases from the hydrofluorocarbon family, preferably in a percentage less than 50%.

[0093] Even more particularly, in the illustrated example, the refrigerant fluid contained in the heat pump evaporator / condenser assembly 5 preferably comprises, at a percentage greater than 75%, one or more gases from the hydrofluoroolefin family.

[0094] Stated another way, the refrigerant fluid preferably consists primarily of one or more gases of the hydrofluoroolefin family.

[0095] Referring only to FIG. 2 , preferably the wastewater treatment machine 1 finally comprises a separation / demister filter 50 positioned inside the vessel 2 below the inlet of the drain line 7 and configured to prevent droplets of liquid drawn upwards by the steam flow from reaching the inlet of the drain line 7, and / or a resistor 51 positioned at the bottom of the vessel 2 and configured to selectively heat the liquid present inside the vessel 2 in addition to or instead of the evaporator / condenser assembly 5.

[0096] Clearly, resistor 51 may be replaced by any other electrical device that generates heat when an electric current is passed through it.

[0097] Specifically, in the illustrated example, the separation / demister filter 50 is preferably located inside the vessel 2 immediately below the heat exchanger 42 .

[0098] Preferably, the electronic control device 9 is configured to command the resistors 51 etc. based on signals coming from one or more temperature sensors positioned inside the container 2 and / or based on some operating parameters of the processing machine 1.

[0099] The operation of the sewage treatment machine 1 can be easily inferred from what has been described above.

[0100] The liquid to be treated is sucked into the reactor / vessel 2 by the effect of the negative pressure created by the vacuum generator 3, without the use of a feed pump.

[0101] The suction pump 16 draws liquid from the bottom of the vessel 2 and delivers it to the heat exchanger 41 of the evaporator / condenser assembly 5, which provides the heat required to evaporate the liquid.

[0102] After passing through the heat exchanger 41 the liquid to be treated re-enters the vessel 2 and, under the effect of the subatmospheric pressure, part of the liquid is instantaneously evaporated (flash evaporated) towards the upper part of the vessel 2 .

[0103] While traveling upwards along vessel 2, the water vapor passes through separator filter 50 which retains larger droplets and then reaches low pressure heat exchanger 42 which causes total or partial condensation of the vapor at the inlet of drain line 7 or along drain line 7. The resulting condensed / distilled liquid accumulates inside tank 24 and is led out of the processor following activation of suction pump 29 and simultaneous opening of control valve 30.

[0104] Non-condensable gases present inside the tank 24 , meanwhile, are vented from the tank 24 using a non-condensable gas release device 28 .

[0105] Apparently, due to evaporation of some of the aqueous solution, the liquid remaining at the bottom of the container 2 will gradually increase in concentration of contaminants until it is discharged / directed outside the treatment machine 1 following the opening of the control valve 19 and the operation of the conveying pump 20.

[0106] The advantages associated with the use of the new refrigerant fluids containing one or more gases of the hydrofluoroolefin family in percentages of more than 3%, and more advantageously more than 30%, are noteworthy.

[0107] Experimental testing highlights that the new refrigerant fluid increases the efficiency of the heat pump evaporator / condenser assembly 5 and simultaneously reduces the GWP index value of the processor.

[0108] Finally, it is apparent that modifications and variations can be made to the above-described sewage treatment machine 1 without departing from the scope of the present invention.

[0109] For example, the non-condensable gas release device 28 may be configured to, upon command, release non-condensable gas outside the tank 24. In this case, the electronic control device 9 may command the non-condensable gas release device 28.

[0110] Also, referring to FIG. 3, in an alternative embodiment, the high pressure heat exchanger 41 of the heat pump evaporator / condenser assembly 5 is positioned adjacent to, and more conveniently in contact with, the bottom of the vessel 2, preferably outside the vessel, so as to transfer heat directly to the liquid present in the bottom of the vessel 2.

[0111] The low pressure heat exchanger 42 is further preferably disposed / housed entirely within the vessel 2, the top of which is preferably configured to temporarily collect condensed liquid dripping from the heat exchanger 42.

[0112] Further, in this embodiment, the sewage treatment machine 1 is preferably provided with a rotatable stirring member 60 positioned inside the vessel / reactor 2 near the bottom of the vessel, the rotatable stirring member 60 being capable of rotating about a given axis of rotation A, preferably substantially coincident with the longitudinal axis of the vessel 2, by a motor assembly 61, preferably electrically operated, the motor assembly 61 being preferably positioned outside the vessel 2 and configured to drive the stirring member 60 to rotate about axis A.

[0113] Preferably, the rotatable stirring member 60 is further configured to scrape the inner surface of the vessel 2 during rotation about the axis A.

[0114] More particularly, the rotatable stirring member 60 is preferably provided with a series of radial vanes angularly distributed about the axis A and extending to skim the inner surface of the vessel 2 .

[0115] Preferably, the rotatable stirring member 60 is further fixedly fixed / fitted to the end of a support shaft 62 which starts from the top, protrudes into the interior of the vessel 2, cantilevers within the vessel 2 and extends coaxially with the axis A and is driven to rotate by a motor assembly 61.

[0116] The motor assembly 61 further comprises an electric gear motor positioned at the top of the vessel 2, preferably outside the vessel 2, and essentially consists of an electric gear motor mechanically coupled to the support shaft 62 so as to be capable of driving the support shaft 62 and everything therewith to rotate about the axis A.

[0117] Preferably, the electronic control device 9 is also configured to command the motor assembly 61 based on certain operating parameters of the processor 1 .

[0118] Also in this embodiment, the refrigerant fluid contained in the heat pump evaporator / condenser assembly 5 comprises one or more gases from the hydrofluoroolefin family in a percentage greater than 3%, more advantageously greater than 30% or even greater than 50%.

[0119] Finally, in an alternative, not shown, embodiment, the vessel / reactor 2 may consist of a large, watertight closed vessel, preferably extending substantially horizontally and substantially cylindrical and oval in shape.

[0120] The rotatable stirring member may also consist of a screw inserted inside the vessel / reactor 2 in an axially rotatable manner substantially coaxially or parallel to the longitudinal axis of the vessel / reactor 2 and optionally dimensioned to scrape the bottom of the vessel / reactor 2 during rotation about the longitudinal axis of the vessel / reactor 2.

[0121] Specifically, the screw is preferably positioned external to the vessel / reactor 2 and is driven to rotate by a motor assembly which is preferably electrically operated. [Explanation of symbols]

[0122] 1. Sewage treatment machine 2. Containers and reactors 3. Vacuum Generator 4 Supply piping 5 Heat Pump Evaporator / Condenser Assembly 6 First drain pipe 7 Second drain pipe 8. Rigid support skeletal structure 9 Electronic Control Devices 10 tubes 11. Regulating valves, control valves 12 Filters 13. Shutoff valve 14 Level sensors, level switches 15 Master 16 Suction pump, circulating pump 17 Shut-off valve 18 Recirculation pipe 19 Control valve 20. Conveyor Pump 21 Shut-off valve 24 Tank 25 First Tube 26 Second Tube 27 Check valve 28 Non-condensable gas release devices 29 Suction Pump 30 Control valve 34 Ejector 35 Circulation Pump 36 Recirculation pipe 37 Shut-off valve 41 High pressure heat exchanger, condenser, first heat exchanger 42 Low pressure heat exchanger, evaporator, second heat exchanger 43 Expansion valve 44 Compressor 45 Auxiliary evaporator, second low pressure heat exchanger 47 Auxiliary heat exchanger 48 Second auxiliary heat exchanger 49 Three-way valve 50 Separation / Demister Filter 51 Resistance 60 Rotatable stirring member 61 Motor assembly A Rotation Axis F1 Stream of treated wastewater f2 Distilled liquid stream f3 Waste liquid flow

Claims

1. a closed vessel (2) in which the liquid to be treated is boiled; a vacuum generating device (3) configured to maintain the interior of the closed vessel (2) at a given pressure having a value less than the environmental / external pressure; a supply pipe (4) for the liquid to be treated, configured to lead the liquid to the interior of the closed vessel (2); a heat pump assembly (5) associated with said closed vessel (2) capable of transferring heat to a liquid present at the bottom of said closed vessel (2), thereby boiling said liquid, and at the same time removing heat from the vapor reaching the top of said closed vessel (2), thereby condensing said vapor and obtaining a distilled liquid; A first drain pipe (6) that branches off from the bottom of the closed container (2) and is configured to guide / transport liquid that accumulates / stagnates at the bottom of the closed container (2) to the outside of the closed container (2); a second drain pipe (7) branching off from the upper part of the closed vessel (2) and configured to guide / transport the vapor formed inside the closed vessel (2) and / or the distilled liquid resulting from the condensation of the vapor to the outside of the closed vessel (2); A sewage treatment machine (1) of the type comprising: The heat pump assembly (5) comprises a refrigerant fluid comprising one or more gases from the family of hydrofluoroolefins in a percentage greater than 3%, the second drain line (7) comprises a tank (24) configured to contain the vapor and / or distilled liquid coming from the closed vessel (2); The heat pump assembly (5) comprises: a first heat exchanger (41) configured to heat the liquid stagnating at the bottom of the closed vessel (2); a second heat exchanger (42) configured to cool / condense the vapor forming inside the enclosed vessel (2); a first expansion member (43) interposed between the first heat exchanger (41) and the second heat exchanger (42) and configured to cause a rapid expansion of the refrigerant fluid directed towards the second heat exchanger (42); a third heat exchanger (45) located inside the tank (24) and connected in parallel with the second heat exchanger (42) so as to be able to cool the distilled liquid and / or vapor located inside the tank (24) of the second drain pipe (7); a second expansion member (46) interposed between the first heat exchanger (41) and the third heat exchanger (45) and configured to cause a rapid expansion of the refrigerant fluid directed towards the third heat exchanger (45); A sewage treatment machine (1) comprising:

2. 2. The sewage treatment machine of claim 1, wherein the refrigerant fluid comprises one or more gases from the family of hydrofluoroolefins in a percentage greater than 30%.

3. 3. The sewage treatment machine of claim 2, wherein the refrigerant fluid comprises one or more gases from the family of hydrofluoroolefins in a percentage greater than 50%.

4. 4. The sewage treatment machine of claim 3, wherein the refrigerant fluid comprises one or more gases from the family of hydrofluoroolefins in a percentage greater than 75%.

5. 5. A sewage treatment machine according to any one of claims 1 to 4, wherein the refrigerant fluid comprises one or more gases from the hydrofluorocarbon family.

6. 2. The sewage treatment machine according to claim 1, wherein the vacuum generating device (3) is configured to continuously maintain the pressure inside the closed vessel (2) at a value less than 0.8 bar.

7. 2. The sewage treatment machine according to claim 1, wherein the supply pipe (4) is configured to control / vary the flow rate of the liquid to be treated entering the obstruction vessel (2) so as to continuously maintain the liquid height inside the obstruction vessel (2) around a given value.

8. 2. The sewage treatment machine of claim 1, wherein the first heat exchanger (41) is positioned along a recirculation pipe (18) of the first drain line (6) or adjacent to a bottom of the enclosed vessel (2).

9. 2. The sewage treatment machine of claim 1, wherein the second heat exchanger (42) is at least partially located inside the enclosed vessel (2) or upstream of the tank (24) along the second drain line (7).

10. The sewage treatment machine additionally comprises a rotatable stirring member (60) located inside the closed vessel (2) near a bottom of the closed vessel and capable of rotating about a given rotation axis (A), and a motor assembly (61) configured to drive the stirring member (60) to rotate about the rotation axis (A), 2. The sewage treatment machine according to claim 1, characterized in that the agitating member (60) is structured to rub against the inner surface of the enclosed vessel (2) during rotation about the rotation axis (A).

11. 2. The sewage treatment machine according to claim 1, further comprising a separating / demister filter (50) located inside the closed vessel (2) below the inlet of the second drain line (7) and configured to prevent droplets of liquid drawn upwards by the steam flow from reaching the second drain line (7).

12. The wastewater treatment machine further comprises a rigid supporting framework (8) configured to be stably placed on the ground, 2. The sewage treatment machine according to claim 1, characterized in that the enclosed vessel (2), the vacuum generating device (3), the supply pipe (4), the heat pump assembly (5), the first drain pipe (6) and the second drain pipe (7) are arranged on the rigid supporting framework (8) to form a single block that is easily transportable.

13. The vacuum generating device (3) an ejector (34) disposed immediately upstream of the tank (24) along a main pipe (25) connecting the tank (24) and an upper portion of the closed vessel (2); a circulation pump (35) disposed along a recirculation pipe (36) directly connecting the tank (24) and the ejector (34); The sewage treatment machine according to claim 1, further comprising:

14. A sewage treatment machine as described in Claim 13, characterized in that the second heat exchanger (42) is positioned along the main pipe (25) immediately downstream of the obstruction vessel (2).

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