Patent Publication Number: US-10760560-B2

Title: Gas displacement pump assembly

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/211,648, filed Aug. 28, 2015, which is incorporated herein by reference as if fully set forth. 
    
    
     FIELD OF THE INVENTION 
     This application relates generally to gas displacement pump assemblies. 
     BACKGROUND 
     Pumping is an example of a method typically used to fill compressed gas cylinders with compressed gasses. According to such a method, a gas material is typically pumped in liquid form through a heat exchanger using a cryogenic pump. The heat exchanger converts the liquid into gas form by increasing the material&#39;s temperature. The gas then exits the heat exchanger and is transferred into compressed gas cylinders. 
     One drawback to conventional methods results from the fact that many liquefied gases, such as helium, may be expensive and difficult to maintain, due for example, to vaporization and resultant pressure changes over time. Further, pumping liquefied helium is impractical, therefore a gas booster pump is used. 
     Pumping liquefied helium with a cryogenic pump also presents challenges. According to conventional methods, a pneumatic gas booster pump must be used to pump helium in order to achieve a higher ultimate pressure than the pressure supplied. However, pneumatic gas booster pumps are slow and require large air compressors to run. These large air compressors are expensive, often being valued many times above the cost of the pump itself. Furthermore, such systems typically generate a great deal of wasted energy and in turn heat, often utilizing exhaust air to cool the pump, as the heat of compression of the pumped gas can result in temperatures in excess of 200° F. if left uncooled. 
     SUMMARY OF THE EMBODIMENTS 
     The application relates to a gas displacement assembly, including: a storage container, a pump that pumps a pressurized gas material into the storage container, a cooling chamber that houses a coolant and cools the gas material to a cryogenic temperature, and a coolant line that transports coolant through the cooling chamber. 
     The application further relates to a gas displacement pump assembly, including: a storage container, a pump that pumps a gas material into the storage container, a vessel housing a supply of coolant, a cooling chamber, a coolant line that transfers coolant from the vessel to the cooling chamber, a gas source, and a gas line that transmits a gas material from the gas source through the cooling chamber and to the pump. The cooling chamber cools the gas material to a cryogenic temperature before the gas material reaches the pump. 
     The application further relates to a method of transferring a gas material into a storage container, including providing the gas material, providing the storage container, and providing a gas displacement pump assembly. The gas displacement pump assembly has a cooling chamber, a pump, a vessel housing a supply of coolant, and a coolant line, and a gas line. The method further includes transmitting coolant from the vessel, and through the coolant line to the cooling chamber, transmitting the gas material through the gas line into the cooling chamber, cooling the gas material to a cryogenic temperature in the cooling chamber to generate a cooled gas material, transmitting the cooled gas material from the cooling chamber to the pump, and pumping the cooled gas material into the storage container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of an embodiment of a gas displacement pump assembly. 
         FIG. 2  is a side elevational view of the assembly of  FIG. 1 . 
         FIG. 3  is a front elevational view of the assembly of  FIG. 1 . 
         FIG. 4  is a schematic illustration of another embodiment of a gas displacement pump assembly. 
         FIG. 5  is a side elevational view of the assembly of  FIG. 4 , 
         FIG. 6  is a front elevational view of the assembly of  FIG. 4 . 
         FIG. 7  is a schematic illustration of another embodiment of a gas displacement pump assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     An embodiment of a gas displacement pump assembly  10  is shown in  FIGS. 1-3 . This embodiment of the assembly may be used for compression and liquefaction of a gas material for storage, as described below. 
     As used in this application and claims, the term “gas material” shall be defined as a material in a gas state at any stage of the transport and storage processes described in this application, and such a material may be referred to as a “gas material” even at times when such a material is in a non-gaseous state, such as a liquid state. 
     As shown, the assembly  10  comprises a coolant vessel  20  that houses a supply of coolant  22 . The vessel  20  is in communication with a cooling chamber  30  via a coolant line  40 . The cooling chamber  30  cools a supply of a gas material transmitted to the cooling chamber via a gas line  60 , before transmitting the gas material to a filling pump  80  that compresses and pumps the gas material through an outlet  12  into a storage container, which may be a suitable gas storage cylinder. 
     Referring to  FIG. 1 , the coolant vessel  20  is formed as a chamber having an interior that houses the coolant  22 . The coolant  22  of this embodiment is liquid nitrogen. The vessel  20  comprises a vapor return port  24  and a liquid supply port  26 , each of which is in communication with a section of the coolant line  40 . 
     The coolant line  40  forms a closed loop that commences at the liquid supply port  26 , where coolant  22  exits the coolant vessel. An exit valve  42  may be located along the coolant line  40  just beyond the liquid supply port  26 , for starting and stopping the flow of coolant  22  out from the vessel  20  via the liquid supply port  26 . The coolant line  40  then travels through the cooling chamber  30  and cooling tower  82 , as described in detail below, and returns to the coolant vessel  20  via the coolant line  40 . The coolant line  40  may be formed of any conventional tubing known in the art that is suitable for transport of a coolant material. A return valve  44  may be located along the coolant line  40  just before it reaches the vapor return port  24  and returns to the coolant vessel  20 , for starting and stopping the flow of coolant  22  back into the vessel  20 . 
     The gas material of this embodiment is helium. Still referring to  FIG. 1 , the gas line  60  transmits the gas material, beginning at a gas source  62 , through the cooling chamber  30 , and then to the pump  80 , which pumps the gas material through the cooling tower  82 , through an outlet  12  leading into the storage container, as described in detail below. The gas line  60  may be formed of tubing material suitable for transport of a gas material in both gaseous and liquid states. 
     As shown, the coolant line  40  and the gas line  60  meet at the cooling chamber  30 , at which point the gas material is cooled before being transferred to the pump  80  via gas line  60 . Referring to  FIG. 2 , the cooling chamber  30  comprises a vacuum insulated receptacle  38  that houses coolant, which is transferred to the cooling chamber  30  via coolant line  40 . The coolant enters the receptacle  38  via coolant feed  108  in a liquid state and forms a bath  46  within the cooling chamber  30 . The gas line  60  extends to the cooling chamber  30 , enters the receptacle  38  at gas feed  110 , and forms a tubing coil  64  immersed in the bath  46 . The tubing coil  64  could be formed of copper to provide optimal heat conduction. The gas material travels through the tubing coil  64  and is cooled by the bath  46  of coolant material within the cooling chamber  30 . The cooling chamber  30  may be provided with a liquid solenoid valve  32  ( FIG. 1 ) liquid level thermocouple  36  for controlling the temperature of the bath  46 , and a relief valve  34  for controlling the pressure in the cooling chamber  30 . The gas material of the embodiment shown may be cooled to cryogenic temperatures, for example, below −320° F./−195° C. in embodiments in which helium is the gas material. 
     Referring to  FIG. 1 , after being cooled in the cooling chamber  30 , the gas material travels to the pump  80  via a section  66  of the gas line  60  extending between the cooling chamber  30  and pump  80 . A reservoir  106  is located along section  66 , and the gas material is fed into the reservoir  106  prior to reaching the pump  80 . The reservoir  106  houses a reserve supply of the gas material, which is fed directly into the pump  80 . Feeding gas material from the reserve supply helps increase efficiency in feeding the gas material to the pump  80  by providing a constant supply to draw from in feeding the gas material into the pump  80 . 
     Section  66  of the gas line  60  splits into first  66 A and second  66 B branches between the pump  80  and reservoir  106 . Branch  66 A includes check valve  84 A, and branch  66 B includes check valve  84 B. Gas material is driven from the reservoir  106  to the pump  80  by check valve  84 B, through branch  66 B. During pumping, some of the gas material may leak. For example, the pump  80  may include a head seal, which may be a common location for such leaks. Seal leak gauge  68  may be provided along section  66 B, to detect such leaks, and check valve  84 B may collect any leaked gas material leaked at the pump  80 , and route it back to the reservoir  106  through branch  66 A, effectively recirculating any leaked gas material back to the pump  80 . 
     In another embodiment, shown in  FIGS. 4-6 , the reservoir  106  could be omitted, and the gas material fed directly from the cooling chamber  30  to the pump  80  via section  66 , and then branch  66 B, driven by check valve  84 B. In such an embodiment, check valve  84 B returns leaked gas material to section  66  of the gas line  60  through branch  66 A, so it can then be recirculated to the pump  80  through branch  66 B. The embodiment of  FIGS. 4-6  is otherwise similar to that of  FIGS. 1-3   
     The pump  80  remains cool during pumping, because the gas material is cooled by the cooling chamber  30  prior to reaching the pump  80 . 
     The pump  80  may be an electrically driven positive displacement gas booster pump, which may be, for example, a belt-driven piston pump. The assembly  10  includes an electric motor  50  that drives the pump  80 . In the embodiment shown, the electric motor  50  may comprise an enclosed, fan cooled electric motor, though other types of electric motors could be employed as well. The pump  80  compresses and transfers the gas material into a cooling tower  82 . 
     In the example shown, the cooling tower  82  is a conventional-type cooling tower that cools the gas material through a heat exchange process known in the art, prior to the gas material being transferred into a storage container via a final section  70  of gas line  66 . The cooling tower  82  includes a check valve  86  to drive the gas material in a direction from the pump  80  and towards the storage container outlet  12  via the section  70  of gas line. The final section  70  of gas line  60  may include a pressure relief valve  72  and gas material thermocouple  74  to ensure proper temperature and pressure of the cooled gas material. Additional pressure relief valves and thermocouples may be provided at others sections of the gas line  60  for similar purposes. 
     The gas line  60  may also include a bypass section  76  that extends directly between the source  62  and final section  70  and includes a bypass section check valve  88  that drives the gas material directly from the source to the storage container. Bypass valves  78  may be provided for allowing and stopping the flow of gas material via the bypass section  76 . 
     Cooling the gas material by the cooling chamber  30  before it is transferred to the pump  80  mitigates the heat generated during compression by the pump  80 , which in turn extends the life of the pump  80 . As the temperature of the gas material is reduced in the cooling chamber  30 , the density of the gas material is increased, which in turn increases the amount of gas molecules pumped through a given area per unit of time, increasing pumping efficiency and reducing the time required to fill the storage container. 
     The coolant travels through the assembly  10  via the coolant line  40 , traveling out of the coolant vessel  20  through outlet  26 , through cooling chamber  30 , from the cooling chamber  30  to the cooling tower  82  by way of section  48 . During this process, the coolant, which is initially provided in a liquid state, may vaporize. The vaporized coolant is utilized in the cooling process that takes place at the cooling tower  82 , and then transported from the cooling tower  82  through final section  54  of coolant line, through vapor return port  24  and back to the coolant vessel  20 . 
     The pumping assembly  10  of the embodiment shown is electrically controlled. As shown in  FIG. 1 , the system  10  further comprises an electrical control line  90 . An electrical control box  92  forms a junction at which multiple sections of the electrical control line  92  meet, for supplying power and controlling the various components of the system  10 . 
     A first section  94  of the electrical control line  90  controls and powers the liquid solenoid valve  32  that regulates liquid level of the cooling chamber  30 . A second section  96  of the electrical control line  90  controls and powers the electric motor  50 . A third section  98  of the electrical control line  90  controls and powers the gas material thermocouple  74 . A fourth section  100  of the electrical control line  90  controls and powers the liquid level thermocouple  36 . 
     The electrical control box  92  may further include an over pressure switch  102  connected with an over pressure section  104  of the gas line  60 . Over pressure section  104  is in communication with the final section  70  of gas line  60 . Over pressure switch  104  acts as a safety mechanism to cut power to the assembly  10  where the pressure of the gas material in the final section  70  is above a selected threshold, to avoid gas at excessive pressure levels being fed into the storage container. 
     Another embodiment of a gas displacement pump assembly  210  is shown in  FIG. 7 . In this embodiment, the gas material is a cryogenic material, and a pump assembly as shown and described may be use to periodically cool such a cryogenic material to maintain a low volume and storage pressure. 
     As shown, the assembly  210  comprises a coolant vessel  220  that houses a supply of coolant  222 . The vessel  220  is in communication with a cooling chamber  230  via a coolant line  240 . The cooling chamber  230  cools a supply of cryogenic material transmitted from a storage container  212  to the cooling chamber  230  via a cryogenic material line  260 , in order to take the cryogenic material from a gaseous to a liquid state before returning the cryogenic material back into the storage container  212 . 
     The cryogenic material of the embodiment shown is argon, which is stored as liquid argon and may, over time, vaporize. The vaporized argon is cooled and liquefied using the assembly  210 , before being returned to the storage container in liquid form, thereby reducing the internal pressure within the storage container  212 . 
     The coolant  222  of this embodiment is liquid nitrogen. The vessel  220  comprises a vapor return  224  and a liquid supply port  226 , each of which is in communication with a section of the coolant line  240 . 
     The coolant line  240  forms a closed loop that commences at the liquid supply port  226 , where coolant  222  exits the coolant vessel  220 . An exit valve  242  may be located along the coolant line  240  just beyond the liquid supply port  226 , for starting and stopping the flow of coolant  222  out from the vessel  220  via the liquid supply port  226 . The coolant line  240  then travels through the cooling chamber  230 , and through cooling tower  280 , before returning to the coolant vessel  220 . The coolant line  240  may be formed of any conventional tubing known in the art that is suitable for transport of a coolant material. As shown, the coolant vessel  220  is formed as a chamber having an interior that houses the coolant  222 . A return valve  244  may be located along the coolant line  240  just before it reaches the vapor return port  224  and returns to the coolant vessel  220 , for starting and stopping the flow of coolant  222  back into the vessel  220 . 
     As shown, the storage container  212  includes a vapor supply port  216  where the cryogenic material flows from the storage container  212  into the cryogenic material line  260  in vapor form, and a liquid return port  214  where the cryogenic material returns to the vessel  220  from the cryogenic material line  260 . The liquid return port  214  may include an entry valve  218  for starting and stopping the flow of cryogenic material into the storage container  212 , and the vapor supply port  216  may include an exit valve  219  for starting and stopping the flow of cryogenic material into the storage container  212 . 
     The cryogenic material line  260  transmits the cryogenic material through a cooling tower  282 , to the pump  280  and through the cooling chamber  230  before returning the cryogenic material to the storage container  212 . The cryogenic material line  260  may be formed of tubing material suitable for transport of a cryogenic material in both gaseous and liquid states. 
     In the example shown, the cooling tower  282  is conventional-type cooling tower that cools the cryogenic material through a heat exchange process known in the art. The cryogenic material line  260  may include first and second check valve  286 A,  286 B that drive the gas material between the cooling tower  282  and the pump  280 . In the embodiment shown, section  270  of the cryogenic material line  260  splits into first  270 A and second  270 B branches between the pump  280  and cooling tower  282 . The cooling tower  282  and check valve  286 A are located along branch  270 A, and check valve  286 B is located along branch  270 B. Cryogenic material travels from the cooling tower  282  to the pump  280  through branch  270 A. During pumping, some of the cryogenic material may leak. For example, the pump  280  may include a head seal, which may be a common location for such leaks. A seal leak gauge  268  may be provided along branch  270 A to detect leaks and pressure differentials at the pump  280 . Check valve  286 B may also collect any leaked gas material leaked at the pump  280 , and route it back to the cooling tower  282  through branch  270 B, effectively recirculating any leaked gas material back to the pump  280 . 
     The pump  280  is an electrically driven positive displacement gas booster pump, which may be, for example, a belt-driven piston pump. The assembly  210  includes an electric motor  250  that drives the pump  280 . In the embodiment shown, the electric motor  250  is a totally enclosed, fan cooled electric motor, though other types of electric motors could be employed as well. 
     After pumping, the cryogenic material then travels via the cryogenic material line  260  from the pump  280  to the cooling chamber  230 . 
     As shown, the coolant line  240  and the cryogenic material line  260  meet at the cooling chamber  230 , at which point the cryogenic material is further cooled before being returned to the storage container  212  via cryogenic material line  260 . The cooling chamber  230  comprises a vacuum insulated receptacle that houses coolant, which is transferred to the cooling chamber  230  via coolant line  240 . The coolant is in a liquid state at the cooling chamber  230  and forms a bath  246  within the cooling chamber  230 . The cryogenic material line  260  extends into the cooling chamber  230  and forms a tubing coil, which may have the same configuration as tubing coil  64  shown in  FIGS. 2 and 3 , immersed in the bath  246 . The tubing coil could be made of copper to provide optimal heat conduction. The tubing coil is cooled by the bath  246  of coolant material within the cooling chamber  230 . The cooling chamber  230  may be provided with a liquid solenoid valve  232  and liquid level thermocouple  236  for controlling the temperature of the bath  246 , and a relief valve  234  for controlling the pressure in the cooling chamber  230 . The cryogenic material of the embodiment shown may be cooled sufficiently to cause liquefaction thereof. The cryogenic material of the embodiment shown may be cooled to cryogenic temperatures, for example, below −302° F./−185° C. in embodiments in which argon is the cryogenic material. 
     The cryogenic material line  260  may include a pressure relief valve  272 , which is provided within section  270  in the illustrated embodiment, as well as a thermocouple  274 , to ensure proper temperature and pressure of the cooled cryogenic material. Additional pressure relief valves and thermocouples may be provided at other sections of the cryogenic material line for the same purposes. At least one check valve  284  may be located along the section  266  cryogenic material line  260  between the cooling chamber  230  and the pump  280 , to drive the cryogenic material in a direction towards the cooling chamber  230  and away from the pump  280 . 
     After exiting the cooling chamber  230 , the cryogenic material is returned to the storage container  212  via section  252  of cryogenic material line  260 . 
     The cryogenic material stored within the storage container  212  may be repeatedly circulated through the cryogenic material line  260  as described above, in order to maintain low temperatures in the cryogenic material. Over time, the temperature of the cryogenic material  212  within the storage container  212  will increase, and some of the cryogenic material will vaporize and then be recirculated and liquefied according the above-described process. 
     Storing the cryogenic material in the storage container  212  in a liquid state reduces the internal pressure within the storage container  212 , allowing the user to retain a liquid product longer and reduce common expenses resulting from pressure relief devices venting the high pressure vapor into the atmosphere. 
     The coolant travels through the assembly  210  via the coolant line  240 , traveling out of the coolant vessel  220  through outlet  226 , through cooling chamber  230 , from the cooling chamber  230  to the cooling tower  282  by way of section  248 . During this process, the coolant, which is initially provided in a liquid state, may vaporize. The vaporized coolant is utilized in the cooling process that takes place at the cooling tower  282 , and then transported from the cooling tower  282  through final section  254  of coolant line, through vapor return port  224  and back to the coolant vessel  220 . 
     The pumping assembly  210  of the embodiment shown is electrically controlled. As shown, the system  210  further comprises an electrical control line  290 . An electrical control box  292  forms a junction at which multiple sections of the electrical control line  292  meet, for supplying power and controlling the various components of the system  210 . 
     A first section  294  of the electrical control line  290  powers and controls the liquid solenoid valve  232  that regulates the liquid level of the cooling chamber  230 . A second section  296  of the electrical control line  290  powers and controls the electric motor  250 . A third section  298  of the electrical control line  290  powers and controls the cryogenic vapor material thermocouple  274 . A fourth section  300  of the electrical control line  290  powers and controls the liquid level thermocouple  236 . 
     The electrical control box  292  may further include an over pressure switch  302  connected with the cryogenic material line  360 . Over pressure switch  304  acts as a safety mechanism to cut power to the assembly  310  where the pressure of the cryogenic vapor material in is above a selected threshold 
     While the invention has been described with reference to the embodiments above, a person of ordinary skill in the art would understand that various changes or modifications may be made thereto without departing from the scope of the claims.