Non-contaminating pressure transducer module

Abstract

A non-contaminating pressure transducer module having an isolation member is disclosed. The isolation member isolates a pressure sensor within the transducer module from exposure to ultra high purity fluids flowing through a conduit in the module without significantly affecting the accuracy of the pressure measurement. The transducer module may be positioned within a fluid flow circuit carrying corrosive materials, wherein the pressure transducer module produces a control signal proportional to either a gauge pressure or an absolute pressure of the fluid flow circuit. The pressure transducer module of the present invention also avoids the introduction of particulate, unwanted ions, or vapors into the flow circuit.

What is claimed is:  
     
       1. A chemically inert pressure transducer module adapted to be connected within a chemically corrosive ultra high purity fluid flow circuit, comprising: 
       (a) a chemically inert housing having a bore extending through at least a portion of said housing, wherein an inlet end of said bore is connected to the fluid flow circuit, said housing further having a cavity formed therein and extending from an outer surface of said housing toward the bore of said housing;  
       (b) a non-fluid conducting pressure sensor positioned within said cavity adjacent said bore for sensing a pressure within the fluid flow circuit;  
       (c) a removable chemically inert isolation member separating said cavity and said bore, said isolation member having first and second opposed major surfaces, said first major surface being exposed to fluid flowing in the bore, said second major surface engaging and adjoining the non-fluid conducting pressure sensor, thereby isolating the pressure sensor from fluid communication with the bore; and  
       (d) means for constraining the pressure sensor against the isolation member in a fixed position within the cavity of the housing.  
     
     
       2. The pressure transducer module as recited in  claim 1 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between first and second sealing members. 
     
     
       3. The pressure transducer module as recited in  claim 1 , wherein said isolation member is formed continuous with said housing and has a thickness dimension ranging between 0.001 and 0.040 inches. 
     
     
       4. The pressure transducer module as recited in claim  3   1 , wherein the housing further has a drain channel extending from the outer surface of the housing into a portion of the cavity that is between the isolation member and a sealing member which seals the pressure sensor to the housing and the isolation member . 
     
     
       5. The pressure transducer module as recited in  claim 1 , wherein an internal surface of the cavity includes first and second sealing members adapted for engaging a lower surface of the pressure sensor. 
     
     
       6. The pressure transducer module as recited in  claim 5 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between the first and second sealing members. 
     
     
       7. The pressure transducer module as recited in  claim 1 , wherein the isolation member has a shape congruent with the bore and is sized to fit within the bore. 
     
     
       8. The pressure transducer module as recited in  claim 5 , wherein the isolation member has a shape congruent with the bore and is sized to fit within the bore. 
     
     
       9. The pressure transducer module as recited in  claim 1 , wherein the pressure sensor is of a capacitive type. 
     
     
       10. The pressure transducer module as recited in  claim 1 , wherein the pressure sensor is of a diaphragm type. 
     
     
       11. The pressure transducer module as recited in  claim 1 , wherein the pressure sensor is of a piezoresistive type. 
     
     
       12. A chemically inert pressure transducer module adapted to be connected within a chemically corrosive ultra high purity fluid flow circuit, comprising: 
       (a) a chemically inert housing having a bore extending through at least a portion of said housing, wherein an inlet end of said bore is connected to the fluid flow circuit, said housing further having a cavity formed therein and extending from an outer surface of said housing into the bore of said housing;  
       (b) a non-fluid conducting pressure sensor positioned within said cavity adjacent said bore for sensing a pressure within the fluid flow circuit;  
       (c) a removable chemically inert isolation member separating said cavity and said bore, said isolation member having first and second opposed major surfaces, said first major surface being exposed to fluid flowing in the bore, said second major surface being adjacent to and adjoining the non-fluid conducting pressure sensor, thereby isolating the pressure sensor from fluid communication with the bore;  
       (d) means for constraining the isolation member against the non-fluid conducting pressure sensor in a fixed position within the cavity of the housing; and  
       (e) an electronic circuit contained within the cavity of the housing and coupled to the non-fluid conducting pressure sensor, whereby the electronic circuit produces an electrical signal proportional to the pressure within the bore.  
     
     
       13. The pressure transducer module as recited in  claim 12 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between first and second sealing members. 
     
     
       14. The pressure transducer module as recited in  claim 12 , wherein an internal surface of the cavity includes first and second sealing members adapted for engaging a lower surface of the pressure sensor. 
     
     
       15. The pressure transducer module as recited in  claim 14 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between the first and second sealing members. 
     
     
       16. The pressure transducer module as recited in  claim 12 , wherein the isolation member has a shape congruent with the bore and is sized to fit within the bore. 
     
     
       17. The pressure transducer module as recited in  claim 14 , wherein the isolation member has a shape congruent with the bore and is sized to fit within the bore. 
     
     
       18. The pressure transducer module as recited in  claim 12 , wherein said pressure sensor includes an annular groove formed on a lower surface of said sensor and being adaptable for receiving a sealing member for sealing said pressure sensor to an internal surface of said housing. 
     
     
       19. A chemically inert pressure transducer module adapted to be connected in-line within a chemically corrosive ultra high purity fluid flow circuit, comprising: 
       (a) a chemically inert housing having a bore extending through at least a portion of said housing, wherein an inlet end of said bore is connected to the fluid flow circuit, said housing further having a cavity formed therein and extending from an outer surface of said housing toward the bore of said housing;  
       (b) a non-fluid conducting pressure sensor positioned within said cavity adjacent said bore for sensing a pressure within the fluid flow circuit, said pressure sensor having an  a sapphire isolation member engaged to a lower planar surface of the pressure sensor; and  
       (c) means for sealably constraining the pressure sensor and isolation member against an opening formed in the housing between the cavity and bore.  
     
     
       20. The pressure transducer module as recited in  claim 19 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between first and second sealing members. 
     
     
       21. The pressure transducer module as recited in  claim 19 , wherein said isolation member is formed continuous with said housing and has a thickness dimension ranging between 0.001 and 0.040 inches. 
     
     
       22. The pressure transducer module as recited in  claim 21 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between a sealing member which seals the pressure sensor to the housing and a second sealing member that seals the isolation member to the pressure sensor. 
     
     
       23. The pressure transducer module as recited in  claim 19 , wherein an internal surface of the cavity includes a  first and second sealing members adjacent the opening and adapted for engaging a lower surface of the isolation member. 
     
     
       24. The pressure transducer module as recited in  claim 23 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between the first and second sealing members. 
     
     
       25. The pressure transducer module as recited in  claim 23 , wherein said isolation member is instead constructed of a material selected from the group consisting of PFA, PTFE, FEP, ETFE, CTFE, ECTFE, PVDF, and PEEK, and sapphire . 
     
     
       26. The pressure transducer module as recited in  claim 19 , wherein the isolation member has a shape congruent with the bore and is sized to fit within the bore. 
     
     
       27. The pressure transducer module as recited in  claim 19 , wherein said isolation member is formed as part of the housing. 
     
     
       28. The pressure transducer module as recited in  claim 19 , wherein the isolation member is replaceable and is manufactured from a chemically inert fluoropolymer. 
     
     
       29. The pressure transducer module as recited in claim  27   19 , wherein said isolation member forms a lower chemically inert layer of the pressure sensor and further includes an annular groove formed in the lower planar surface of the pressure sensor . 
     
     
       30. The pressure transducer module as recited in  claim 19 , wherein an edge proximate the lower planar surface of the pressure sensor is beveled. 
     
     
       31. The pressure transducer module as recited in  claim 20 , further including a fluid sensor positioned proximate the drain channel for detecting the presence of fluids within the drain channel. 
     
     
       32. A chemically inert pressure transducer module adapted to be connected within a chemically corrosive ultra high purity fluid flow circuit, comprising: 
       (a) a housing having a bore extending through at least a portion of said housing, wherein an inlet end of said bore is connected to a fluid flow circuit, said housing further having a cavity formed therein and extending from an outer surface of said housing toward the bore of said housing;  
       (b) a non-fluid conducting pressure sensor positioned within said cavity adjacent said bore for sensing a pressure within the fluid flow circuit;  
       (c) an removable isolation member separating said cavity and said bore, said isolation member having first and second opposed major surfaces, said first major surface being exposed to fluid flowing in the bore, said second major surface engaging and adjoining the pressure sensor, thereby isolating the pressure sensor from fluid communication with the bore; and  
       (d) means for positioning at least a portion of said pressure sensor and said isolation member in a fixed position within the cavity of the housing.  
     
     
       33. The pressure transducer module as recited in  claim 32 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between first and second sealing members. 
     
     
       34. The pressure transducer module as recited in  claim 32 , wherein said isolation member is formed continuous with said housing. 
     
     
       35. The pressure transducer module as recited in claim  34   32 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity. 
     
     
       36. The pressure transducer module as recited in  claim 32 , wherein the pressure sensor is of a capacitive type. 
     
     
       37. The pressure transducer module as recited in  claim 32 , wherein the pressure sensor is of a diaphragm type. 
     
     
       38. The pressure transducer module as recited in  claim 32 , wherein the pressure sensor is of a piezoresistive type. 
     
     
       39. The pressure transducer module as recited in  claim 32 , wherein the pressure sensor is of a sapphire diaphragm type. 
     
     
       40. The pressure transducer module as recited in  claim 32 , wherein the isolation member is removable. 
     
     
       41. The pressure transducer module as recited in claim  40   32 , wherein the housing further has a drain channel extending from the outer surface of the housing into the cavity between a sealing member which seals the pressure sensor to the housing and a second sealing member that seals the isolation member to the pressure sensor. 
     
     
       42. The pressure transducer module as recited in claim  40   32 , wherein said isolation member is constructed from a material selected from the group consisting of PFA, PTFE, FEP, ETFE, CTFE, ECTFE, PVDF, PEEK, and sapphire. 
     
     
       43. The pressure transducer module as recited in  claim 32 , wherein said isolation member is formed as a lower layer of the pressure sensor. 
     
     
       44. The pressure transducer module as recited in  claim 43 , wherein said isolation member is constructed of sapphire. 
     
     
       45. The pressure transducer module as recited in claim  32   41 , further including a fluid sensor positioned proximate the drain channel for detecting the presence of fluids within the drain channel. 
     
     
       46. A chemically inert pressure transducer module adapted to be connected within a corrosive fluid flow circuit, said pressure transducer module comprising: 
       ( a )  a housing having an inlet suitable for coupling to a fluid flow circuit;    
       ( b )  a non - fluid conducting pressure sensor contained within said housing and isolated from the fluid flow circuit;    
       ( c )  a vent extending from an outer surface of said housing into a first chamber of the housing between first and second sealing members, wherein at least a bottom portion of said pressure sensor is sealed within said first chamber and an electrical circuit coupled to said pressure sensor is contained within a second chamber of said housing; and    
       ( d )  an isolation member isolates the pressure sensor within the housing from the fluid flow circuit, an internal surface of the housing including the first and second sealing members that seal the isolation member to said housing.   
     
     
       47. The pressure transducer module as recited in  claim 46 , wherein the housing further has a second vent extending from the outer surface of the housing into said second chamber. 
     
     
       48. The pressure transducer module as recited in  claim 46  wherein said isolation member is formed continuous with said housing and has a thickness dimension ranging between  0 . 001  and  0 . 040  inches. 
     
     
       49. The pressure transducer module as recited in  claim 46 , wherein said isolation member is constructed from the group consisting of PFA, PTFE, FEP, ETFE, CTFE, ECTFE, PVDF, PEEK, and sapphire.  
     
     
       50. The pressure transducer module as recited in  claim 46 , wherein the isolation member has a shape congruent with the inlet and is sized to fit within the inlet.  
     
     
       51. The pressure transducer module as recited in  claim 46 , wherein the isolation member is removable.  
     
     
       52. The pressure transducer module as recited in  claim 46 , wherein said isolation member forms a lower layer of the pressure sensor.