Differential pressure transducer

• US 5,024,294 A
• Filed: 06/07/1990
• Issued: 06/18/1991
• Est. Priority Date: 06/07/1990
• Status: Expired due to Fees

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Service Company
• Inventors: DeWitt, Donald E., Spence, Scott L., Van Fossen, Robert A.
• Primary Examiner(s): Husar, Stephen F.
• Assistant Examiner(s): Cariaso, Alan B.
• Application Number:
  US07/534,457
• Time in Patent Office: 376 Days
• Field of Search: 184/6.4, 184/108, 417/13, 417/19, 417/38, 417/44, 73/722, 73/728, 340/626, 340/451
• US Class Current: 184/108
• CPC Class Codes: F01M 1/22 rendering machines or engines inoperative or idling on pressure failure
• CPC Class Codes: G01L 9/14 involving the displacement of magnets, e.g. electromagnets

Abstract

A differential pressure sensor indicating a housing forming a high pressure chamber, a nozzle mounted on the housing at one end of the chamber, a diaphragm mounted in the chamber to form a low pressure chamber in the nozzle, a spring retainer in the high pressure chamber, a spindle connected to the diaphragm, a tension spring connecting the spindle to the spring retainer, a circular magnet mounted on the spindle and a transducer mounted on the housing to sense the position of the magnet.

Claims

1. A differential pressure sensing device for monitoring the pressure differential between the discharge pressure and the crankcase pressure of a lubricating pump for a compressor, said device comprising:

a housing having a high pressure chamber,

a nozzle mounted on said housing and having a low pressure chamber,

a diaphragm separating said high pressure chamber from said low pressure chamber,

a tension spring mounted in said high pressure chamber,

a magnet carrier assembly connecting said spring to said diaphragm, means in said device for connecting said high pressure chamber to the discharge side of said lubricating oil pump, means in said device for connecting said low pressure chamber to the crankcase, and

means mounted in said housing for sensing the axial position of said magnet carrier assembly.

2. The device according to claim 1 wherein said magnet assembly includes a carrier and a ring magnet having an angular disposition of which does not affect the response characteristics of said sensing means.

3. The device according to claim 1 including means for adjusting the differential pressure response.

4. The device according to claim 1 wherein said high pressure connecting means includes a knurled section defining a high pressure flow path to said high pressure chamber.

5. The device according to claim 1 including means for limiting the motion of said carrier assembly.

6. The device according to claim 5 wherein said limiting means including a retainer mounted on each side of said diaphragm for sealing said diaphragm on said rod.

7. A pressure differential sensor comprising:

a housing,

a chamber in said housing,

a device mounted on one end of said housing,

said device including means for connecting said chamber to a high pressure source,

a diaphragm mounted in said device for separating said chamber in said housing from said device,

means in said device for connecting said diaphragm to a low pressure source,

a rod positioned in said high pressure chamber and being connected to respond to the movement of said diaphragm,

a tension spring connecting said rod to said housing whereby said rod is centered and free to move with said diaphragm, and

means mounted on said rod for indicating the position of said rod in response to changes in the pressure differential between said chambers.

8. The sensor according to claim 7 including means for monitoring the position of said indicating means.

9. The sensor according to claim 7 including means for limiting the motion of said spindle to prevent overstressing of the diaphragm.

10. The sensor according to claim 7 including means for adjusting the tension of the spring to vary the response characteristic of said rod.

11. A differential pressure sensor comprising:

a housing having a chamber,

a threaded opening at one end of said chamber,

a nozzle mounted in said housing at the other end of said chamber,

a spindle positioned in said chamber in said housing,

a diaphragm mounted on one end of said spindle and being connected to said nozzle to define a low pressure chamber in said nozzle and a high pressure chamber in said housing,

a spring retainer mounted in said threaded opening in said one end of said chamber, and

a tension spring connecting said spindle to said retainer,

a magnet mounted on said spindle, and

means mounted on said housing for sensing the position of said magnet in said chamber.

12. The sensor according to claim 11 wherein said nozzle includes a knurled section for defining a flow path into said high pressure chamber and a bore through said nozzle for defining a flow path into said low pressure chamber.

13. The sensor according to claim 12 including means for limiting the motion of said spindle in said chamber.

14. A pressure sensing device for monitoring the pressure differential between the lubricating oil discharge pressure and the crankcase pressure in a compressor, said device comprising a housing having a chamber,

a device mounted on said housing, said device including passage means for connecting said chamber to discharge pressure and a bore in said device connected to said crankcase,

a diaphragm in said housing separating said chamber from said bore,

a spindle mounted in said chamber and being connected to said diaphragm,

a tension spring connected to said spindle and to said housing whereby said spindle is suspended in said chamber between said diaphragm and said spring, and

means mounted on said spindle for indicating the position of said spindle in said housing.