Abstract:
A multi-diaphragm injection pump, having the driving diaphragm and the injection diaphragm joined together by means of a connecting rod so as that any movement of the driving diaphragm will result in an equal movement of the injection diaphragm, these two diaphragm being controlled by a mechanical micro-valve which is engaged by the connecting rod and therefore allows for the automatic actuation of the driving diaphragm which will drive the injection diaphragm which will cause any fluid to be drawn into the fluid chamber and then discharged at a higher pressure.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to the field of injection pumps, and more particularly to a multi-diaphragm pump for injecting chemicals into a pressurized process such as a gas well.  
       SUMMARY OF THE INVENTION  
       [0002]     The present invention is directed to an injection pump comprising a pressure chamber, a driving diaphragm, a fluid chamber, an injection diaphragm, a connecting rod, and a control unit. The pressure chamber has an inlet port and the driving diaphragm is disposed in the pressure chamber. The fluid chamber comprises a fluid supply port connectable to a fluid source and an outlet port. The injection diaphragm is disposed in the fluid chamber. The connecting rod is operatively connected to the driving diaphragm and the injection diaphragm. The control unit operatively engages the connecting rod and is adapted to supply a pressurized fluid to the inlet port of the pressure chamber. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0003]      FIG. 1  illustrates a cross-section view of a pump built in accordance with the present invention.  
         [0004]      FIG. 2  illustrates the pump of  FIG. 1  in an exhaust mode.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0005]     Gas and oil well drilling and pumping operations are generally done under pressurized conditions. The production and transmission of oil and gas are also done under pressurized conditions. The pressurized processes frequently require chemicals be injected into the process for various reasons. Pumps are used for injecting chemicals or other fluids into the pressurized process. In certain operations for example, appropriate chemicals may be injected to a process for enhanced fluid expulsion or to neutralize corrosive situations. Alternatively, a chemical such as methanol may be required to keep fluids from freezing where pressure fluctuations cause significant temperature drops in fluid.  
         [0006]     The present invention is directed to an improved pump for use in injecting chemicals to a pressurized process, such as a gas well application. The invention comprises a multi-diaphragm pump for high (approx. &gt;100 psi) or very high pressure (approx. &gt;1500 psi) applications. The pump provides fluid at a high pressure with a relatively small input pressure. The pump uses a larger driving diaphragm for the input and a smaller injection diaphragm, combined with a connecting shaft, to provide amplification of the input pressure. One skilled in the art will appreciate that relationship may be a function of the diameter of the driving diaphragm and the diameter of the connecting shaft. Preferably the ratio of a diameter of the driving diaphragm to the injection diaphragm is approximately 64:1. A preferred diameter for the driving diaphragm may be eight inches. The preferred diameter for the connecting shaft is one inch. Sealed fluid cavities at both diaphragms help to prevent corrosion and wear of the pump.  
         [0007]     With reference now to the drawings and to  FIG. 1  in particular, there is shown therein an injection pump built in accordance with the present invention. The pump, designated by reference numeral  10 , comprises a pressure chamber  12  having a driving diaphragm  16  disposed therein and a fluid chamber  14  having an injection diaphragm  18  disposed therein. The diaphragms  16  and  18  are joined by a connecting rod  20 . The connecting rod  20  is preferably disposed within a housing  22  that bridges the chambers  12  and  14 . A control unit  24  is operatively connected to the connecting rod  20  and adapted to supply a pressurized fluid to the pressure chamber  12 . The pump  10  may further comprise a pump stand  26  and a pump handle  28  for ease of use and handling.  
         [0008]     The pressure chamber  12  comprises a casing  30  forming a chamber  32  and enclosing the driving diaphragm  16 . The casing  30  comprises a diaphragm cover  34  and a pressure chamber base  36 . The diaphragm cover  34  and chamber base  36  may be bolted together, forming the chamber  32 . The driving diaphragm  16  is disposed in the chamber  32  and forms a sealed pressure cavity  38  in the chamber on a pressured side of the diaphragm. The pressure chamber  12  further comprises an inlet port  40  formed in the diaphragm cover  34 . The inlet port  40  provides for a connection to a source of pressurized fluid, yet to be described. In operation, pressurized fluid will fill the sealed cavity  38  on the pressured side of the diaphragm  16 .  
         [0009]     The fluid chamber  14  comprises a fluid case  42  forming a chamber  44  and enclosing the injection diaphragm  18 . The fluid case  42  comprises a fluid body cover  46  and a fluid base  48 . The fluid body cover  46  and base  48  may be bolted together, forming the chamber  44 . The injection diaphragm  18  is disposed in the chamber  44  and forms a sealed fluid cavity  50  on a pumping side of the injection diaphragm. The fluid chamber  14  further comprises a fluid supply port  52  and an outlet port  54  formed in the fluid body cover  46 . The fluid supply port  52  is connectable to a fluid source (not shown) for the fluid to be injected by the pump  10  into the pressurized process (not shown). In the preferred embodiment, a suction check valve  55  is used to connect the supply port to the fluid source. The fluid enters the fluid chamber  14  through the supply port  52  into the fluid cavity  50 . The outlet port  54  is operatively connected to the pressurized process. Fluid from the fluid cavity  50  is pumped from the cavity through the outlet port  54  to the pressurized process.  
         [0010]     In the preferred embodiment, a connecting tee  56  is connected to the outlet port  54  of the fluid chamber  14 . The connecting tee comprises a first outlet  58  and a second outlet  60 . A discharge check valve  62  is connected to the first outlet  58  of the connecting tee  56 . The discharge check valve  62  is further connected to the pressurized process. A priming valve  64  is preferably attached to the second outlet  60  of the connecting tee  56 , to allow for further regulation of the flow of fluid to the pressurized process.  
         [0011]     The connecting rod  20  is operatively connected to the driving diaphragm  16  and the injection diaphragm  18 . The connecting rod  20  is preferably of rigid construction, formed of steel, iron or other suitable material. Preferably, flange bolts  66  and  67  may be used to secure the diaphragms  16  and  18  to the connecting rod  20 . The connections between the connecting rod  20  and the diaphragms  16  and  18  are such that any movement in the driving diaphragm  16  will result in a coordinated movement in the injection diaphragm  18 . The connecting rod  20  may be of any length appropriate for the size of the pump  10  and its application. A stroke length of the connecting rod  20  may also be selected as appropriate for the diaphragms  16  and  18  and the pump  10  application. In the preferred embodiment, the stroke length of the connecting rod  20  is ¼ inch.  
         [0012]     A diaphragm plate  68  is used between the diaphragm  16  and the connecting rod  20  to provide a working diaphragm surface and support for the flange bolt  66  connection. The diaphragm plate  68  is preferably of a diameter that allows for a selected input ratio for the pump  10 . In the preferred embodiment, the diameter of the plate  68  is eight inches, although the size of the plate is a design consideration. The connecting rod  20  also has a diameter that provides a working surface of the injection diaphragm  18  and is significant to the output of the pump  10 . In the preferred embodiment, the diameter of the connecting rod  20  is one inch, although the diameter of the rod is a design consideration. Alternatively, a diaphragm plate  69  may be used to increase the working surface of the injection diaphragm  18 .  
         [0013]     The connecting rod  20  is preferably disposed in the housing  22 . The housing  22  may be formed of cast iron or other like materials. The durable construction of the housing  22  provides protection for the connecting rod  20  from corrosion and wear inherent to use of the pump  10 . The housing  22  further comprises at least one vent  70 . The vent  70  allows for any fluid leaked into the housing  22  to be exhausted so that pressure does not build in the housing around the connecting rod  20 .  
         [0014]     The housing  22  is connected at a first end  72  to the pressure chamber  12  and at a second end  74  to the fluid chamber  14 . Preferably, the housing  22  is connected to the pressure chamber base  36  of the pressure chamber  12  at the first end  72  of the housing, and to the fluid base  48  of the fluid chamber  14  at the second end  74  of the housing. The housing  22  may be welded or secured by other means. Alternatively, the housing  22  may be integrally formed with the pressure chamber base  36  of the pressure chamber  12  and the fluid base  48  of the fluid chamber  14 .  
         [0015]     A biasing spring  76  is preferably disposed around the connecting rod  20  and proximate the driving diaphragm  16 . In the preferred embodiment, the spring  76  is disposed in the pressure chamber  12 . The spring  76  is positioned between the diaphragm plate  68  and the pressure chamber base  36 . Alternatively, where the housing  22  is integrally formed with the pressure chamber base  36 , a ridge  78  or other surface may be provided in the housing  22  for the spring  76  to work on. The biasing spring  76  is preferably positioned to bias the diaphragms  16  and  18  and the connecting rod  20  in a relaxed state when the spring is extended. As shown in  FIG. 1 , and as to be further discussed below, when the diaphragms  16  and  18  are in the relaxed state the pump  10  will be in a supply mode. When the biasing spring  76  is compressed, as shown in  FIG. 2  and as to be further discussed below, the pump  10  is in an exhaust mode where the pressure in the pressure chamber  12  has built causing the fluid in the fluid chamber  14  to be delivered to the pressurized process.  
         [0016]     With reference again to  FIG. 1 , the control unit  24  is preferably positioned on the housing  22  and operatively connected to the connecting rod  20 . The control unit  24  comprises a fluid inlet  80 , a fluid supply port  82 , and an exhaust valve  84 . The fluid inlet  80  is connectable to a remote source of pressurized fluid (not shown). The fluid supply port  82  is operatively connected to the inlet port  40  of the pressure chamber. The exhaust valve  84  allows pressurized fluid to be released from the control unit  24 . The control unit  24  functions to deliver pressurized fluid received from the source of pressurized fluid to the pressure chamber  12 . In the preferred embodiment, the control unit  24  delivers pressurized air or gas. However, the pressurized fluid may alternatively be in liquid form.  
         [0017]     The control unit  24  is further operatively connected to the connecting rod  20 . The control unit  24  operates to sense the movement and position of the connecting rod  20  so that pressurized fluid is supplied to the pressure chamber  12  when the pump  10  is in a supply or inject mode. For sensing the position of the connecting rod  20 , the control unit  24  may comprise a movable switching arm  86 . The switching arm  86  is connected to the connecting rod  20  and indicates when the connecting rod is in the supply mode or the exhaust mode. A control unit  24  suitable for use with the present invention is available in the micro valve line of control valves available from Invalco, Inc.  
         [0018]     Operation of the pump  10  is as follows. In the supply mode, there is a lack of pressure buildup or pressurized fluid in the sealed pressure cavity  38  of the pressure chamber  12 . The spring  76  is extended and positions the diaphragms  16  and  18  and the connecting rod  20  in the biased or relaxed state as shown in  FIG. 1 . The positioning of the switch arm  86  of the control unit  24  causes the control unit to pass pressurized fluid to the pressure chamber  12 . At substantially the same time, fluid is drawn into the fluid cavity  50  of the fluid chamber  14  through the suction check valve  55 .  
         [0019]     When the pressure level in the pressure cavity  38  of the pressure chamber  12  builds, the driving diaphragm  16  will move and the pump  10  will go to exhaust mode, as shown in  FIG. 2 . Movement of the driving diaphragm  16  will cause the spring  76  to compress and a resultant move by the connecting rod  20 . Movement of the connecting rod  20  will consequently cause the injection diaphragm  18  to move. As the injection diaphragm  18  is moved, fluid in the fluid cavity  50  of the fluid chamber  14  will be discharged at pressure through the discharge check valve  62  and to the pressurized process.  
         [0020]     In the exhaust mode, the switch arm  86  of the control unit  24  will be in the position shown in  FIG. 2 . The positioning of the switch arm  86  will cause the control unit  24  to exhaust the pressure cavity  38  of the pressure chamber  12 . As the pressure in the pressure cavity  38  drops, the spring  76  will again extend, causing the driving diaphragm  16  to retract again to supply mode. The connecting rod  20  and injection diaphragm  18  will also retract, allowing the pump  10  to cycle again.  
         [0021]     Although the present invention has been described with respect to specific preferred embodiments, various changes, modifications, and substitutions of parts and elements may be suggested to one skilled in the art. Consequently, the invention should not be restricted to the above embodiments and it is intended that the present invention encompass such changes, modifications, and substitutions of parts and elements without departing from the spirit and scope of the invention.