Patent EA-001508-B1 (EA)
Title: Fluid flow controller apparatus, actuator and method producing thereof
Inventor: MULLER CHARLES E
IPC: F16K31/02
Filed: 1998-02-11
Abstract: 1. Fluid flow controller apparatus, comprising an inlet plenum and an outlet separated by a partition that has an aperture extending between said inlet plenum and said outlet, said inlet plenum being connected to a source of gas that maintains gas in said inlet plenum at an inlet plenum pressure sufficiently greater than an outlet pressure in said outlet to cause a sonic choked flow of the gas through the aperture from the inlet plenum to the outlet, a valve positioned to open and close said aperture,  wherein said valve includes a valve seat for said inlet opening, and said closure member positioned adjacent said valve seat to provide closing of said inlet opening and connected to said actuator, said actuator being responsive to move the closure member between an open position, which allows unchoked flow of the gas between the closure member and the partition to the aperture and sonic choked flow of the gas in the aperture, and a closed position that prohibits flow of the gas through the aperture; an elongated actuator arm comprising a first layer of piezoelectric material laminated with a second material, said first piezoelectric material being expansive more than said second material in response to a voltage of one polarity and being contractive more than said second material in response to a voltage of an opposite polarity, said actuator is encapsulated with a layer of metal cladding, a controller connected to the actuator in a manner that causes the actuator to oscillate the valve back and forth in a substantially digital manner between the open position and the closed position in a time-modulated cycle that sets effective mass flow rate of fluid flowing through the aperture at somewhere between a maximum flow set point that would occur if the valve would remain always in the open position and a minimum flow set point that would occur if the valve would remain always in the closed position. 2. The apparatus of claim 1, wherein said aperture includes an orifice throat restriction. 3. The apparatus of claim 2, wherein said orifice throat restriction is at said inlet opening. 4. The apparatus of claim 2, wherein said orifice throat restriction is at said outlet opening. 5. The apparatus of claim 2, wherein said orifice throat restriction is between said inlet opening and said outlet opening 6. The apparatus of claim 1, wherein said aperture includes a nozzle between said inlet opening and said outlet opening, wherein said nozzle includes a converging section tapered radially inwardly to a restricted throat and a diverging section tapered radially outwardly from the restricted throat to the outlet opening. 7. The apparatus of claim 1, wherein said actuator includes a solenoid. 8. The apparatus of claim 1, wherein said closure member has a flat surface that is larger than said valve seat. 9. The apparatus of claim 8, wherein said closure member is a disc. 10. The apparatus of claim 1, where said second material is a second piezoelectric material that contracts when said first piezoelectric material expands and that expands when said first piezoelectric material contracts. 11. The apparatus of claim 1, including an actuator driver circuit that produces actuator driver signals of time modulated alternating positive voltages and negative voltages connected to the bender device. 12. The apparatus of claim 11, including a time modulation controller associated with the actuator driver circuit, said actuator driver circuit being responsive to said time modulation controller in a manner that produces said positive voltages and said negative voltages in duty cycles that comprise set ratios of time that the valve is in the open position to total time for the valve to oscillate through an entire cycle of open position and close position. 13. The apparatus of claim 11, in which said time modulation controller is adjustable in a manner that adjusts the duty cycle. 14. The apparatus of claim 1, wherein said metal cladding is stainless steel. 15. The apparatus of claim 1, including a dielectric layer positioned between said bender device and a layer of metal cladding. 16. The apparatus of claim 15, wherein said dielectric layer comprises Parylene<TM>. 17. The apparatus of claim 16, wherein said Parylene<TM> dielectric layer is sputter coated on to said bender device. 18. An actuator comprising said bender device including, at least, one piezoelectric element, wherein said bender device is encapsulated with a layer of metal cladding, which is corrosion-resistant than piezoelectric device. 19. The actuator of claim 18, wherein the cladding material comprises metal. 20. The actuator of claim 19, wherein the metal is stainless steel. 21. The actuator of claim 20, wherein the metal is SS316 steel. 22. The actuator of claim 19, wherein comprises a dielectric layer positioned between said piezoelectric bender device and a cladding material. 23. The actuator of claim 22, wherein the dielectric material is plastic. 24. The actuator of claim 23, wherein the plastic is sputter coated onto a substrate. 25. The actuator of claim 24, wherein the plastic is Parylene<TM>. 26. The actuator of claim 22, wherein the dielectric material comprises aluminum oxide. 27. The actuator of claim 22, wherein comprises the substrate material positioned between said piezoelectric bender device and a dielectric material. 28. The actuator of claim 27, wherein the substrate material comprises metal. 29. The actuator of claim 28, wherein the substrate material comprises nickel. 30. A piezoelectric actuator for use in a corrosion medium comprising, at least, one piezoelectric device, a metallic layer of a substrate applied onto the piezoelectric device, a layer of a dielectric material aqpplied onto the metallic layer of the substrate and a cladding metal applied onto the dielectric layer. 31. A piezoelectric actuator of claim 30 wherein the substrate metallic layer is nickel. 32. A piezoelectric actuator of claim 30 wherein the dielectric layer comprises plastic. 33. A piezoelectric actuator of claim 32 wherein the plastic is sputter coated onto the substrate. 34. A piezoelectric actuator of claim 33 wherein the dielectric layer has a thickness less than 0,0254 mm. 35. A piezoelectric actuator of claim 33 wherein the plastic is Parylene<TM>. 36. A piezoelectric actuator of claim 30 wherein the cladding metal is stainless steel. 37. A piezoelectric actuator of claim 36 wherein the metal is SS316 stainless steel. 38. A piezoelectric actuator of claim 30 wherein the cladding metal has a thickness less than 0.0254 mm. 39. A piezoelectric actuator for use in mediums comprising extremely reactive or corrosion gases, such as fluoro and other halogens, comprising a bender device including two elongated piezoelectric elements laminated with a current-conducting metal between two piezoelectric devices, a metallic layer of a substrate applied onto the piezoelectric bender device, and a stainless steel cladding which encapsulates the dielectric bender device and the substrate metallic layer, including a dielectric layer, positioned between the stainless steel clading and the substrate metallic layer. 40. A piezoelectric actuator of claim 39, wherein both the dielectric layer and the stainless steel cladding have thickness less than 0,0254 mm. 41. A piezoelectric actuator of claim 39, wherein comprises a closure member fixed to the piezoelectric bender device by an adhesive, and a stainless steel cladding also coated with said adhesive. 42. A piezoelectric actuator of claim 41, wherein the dielectric layer is positioned between the adhesive and the piezielectric bender device. 43. A methiod of producing an actuator, which comprises, at least, one piezoelectric device, comprising applying the substrate metallic material onto the piezoelectric device, applying the dielectric material onto the substrate material and applying a metal cladding, which is more corrosion-resistant than the piezoelectric device, onto the dielectric material. 44. The method of claim 43 comprising sputter coating of the dielectic material onto the substrate material by precipitating a plastic on the substrate material. 45. The method of claim 44 comprising sputter coating of the plastic onto the substrate material. 46. The method of claim 44 in which the thickness of the plastic sputter coated onto the substrate material is 0,0254 mm. 47. The method of claim 45, wherein the plastic is Parylene<TM>. 48. The method of claim 43, wherein the substrate metallic layer comprises nickel. 49. The method of claim 43, wherein comprising applying a metal cladding layer onto the dielectric material by precipitating a stainless steel coating to the dielectric layer. 50. The method of claim 49, wherein the stainlee steel coating has a thicknee less than 0,0254 mm. 51. The method of claim 50, wherein the stainless steel coating is SS316 steel. 52. The method of claim 49, comprising fixing the stainless steel closure member to the a part of the dielectric layer by an adhesive prior to sputter coating of a stainles steel and further precipitating the stainless steel for encapsulating the piezoelectric device, the substrate metallic layer, dielectric layer and the adhesive with a stainless steel coating.