Pressure monitoring device

• US 4,194,974 A
• Filed: 12/05/1977
• Issued: 03/25/1980
• Est. Priority Date: 12/03/1976
• Status: Expired due to Term

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro AB (Baxter International Inc.)
• Inventors: Jonsson, Ulf L. P.
• Primary Examiner(s): Spear, Frank A.
• Application Number:
  US05/857,823
• Time in Patent Office: 841 Days
• Field of Search: 210/22, 210/40, 210/321 B, 128/214 E, 116/70, 200/81.5, 200/83 H, 200/83 P, 200/330, 200/334, 200/61.6, 200/76, 200/78, 200/81 R, 200/81 H, 200/82 A, 200/82 C, 200/82 R
• US Class Current: 210/90
• CPC Class Codes: H01H 35/26 Details

Abstract

A pressure monitoring device is disclosed which is adapted to couple a source of fluid with a tripping device. The tripping device includes a tripping switch movable between a first position in which a tripping signal is generated and a second position in which a tripping signal is not generated, and biasing means for biasing the tripping switch into the first position. The pressure monitoring device comprises pressure transmission means which is operable in a first mode and in a second mode, and coupling means having a first position and a second position. The pressure transmission means when operating in the first mode is responsive to the pressure of the fluid being monitored and when operating in the second mode is independent of the pressure of the fluid. The coupling means is operatively associated with the pressure transmission means and the tripping device for coupling the pressure transmission means to the tripping device. The coupling means transmits a pressure signal proportional to the pressure of the fluid to the tripping switch when the coupling means is in the first position and the pressure transmission means is operating in the first mode whereby the tripping device generates a tripping signal when the pressure of the fluid passes a predetermined limit. Further, the coupling means forces the tripping switch into the second position independent of the pressure of the fluid when the coupling means is in the second position.

Claims

1. A pressure monitoring device adapted to couple a pressurized fluid conduit with a tripping device, said tripping device including a tripping switch movable between a first position in which a tripping signal is generated and a second position in which a tripping signal is not generated, and biasing means for biasing said tripping switch into said first position, the pressure monitoring device comprising:

pressure transmission means operable in a first mode and in a second mode, said pressure transmission means when operating in said first mode being responsive to the pressure of the fluid in the pressurized fluid conduit, and when operating in said second mode being independent of the pressure of the fluid in the pressurized fluid conduit; and

coupling means operatively associated with said pressure transmission means and said tripping device for coupling said pressure transmission means to said tripping device, said coupling means being positionable in a first position and in a second position, said coupling means transmitting a pressure signal proportional to the pressure of the fluid in the pressurized fluid conduit to said tripping switch when said coupling means is positioned in said first position and said pressure transmission means is operating in said first mode whereby said tripping device generates a tripping signal when the pressure of the fluid passes a predetermined limit, and said coupling means biasing said tripping switch towards said second position independent of the pressure of the fluid in the pressurized fluid conduit when said coupling means is positioned in said second position.

2. The pressure monitoring device of claim 1 wherein said pressure transmission means is movable when operating in said first mode in response to the pressure of said fluid;

and wherein said coupling means comprises spring means having a first spring position and a second spring position, said spring means being interposed between said pressure transmission means and said tripping switch, and said spring means when in said first spring position directly coupling said pressure transmission means to said tripping switch so that movement of said pressure transmission means causes movement of said tripping switch, and said spring means when in said second spring position biasing said tripping switch toward said second position independent of movement of said pressure transmission means.

3. The pressure monitoring device of claim 2 wherein said spring means comprises a plate spring and spring holding means for fixably holding the ends of said plate spring at a distance apart from one another less than the length of said plate spring.

4. The pressure monitoring device of claim 3 wherein said spring holding means is fixably supported by said presssure transmission means.

5. The pressure monitoring device of claim 1 further including a housing in which said pressure transmission means is supported for relative movement with respect thereto;

and wherein said pressure transmission means comprises sensing means within said housing for sensing the pressure of the fluid in the pressurized fluid conduit when said pressure transmission means is operating in said first mode, and a transmission member extending through said housing and operatively connected to said sensing means for movement with respect to said housing in response to the pressure sensed by said sensing means, the relative position of said transmission member with respect to said housing being indicative of the pressure sensed by said sensing means.

6. The pressure monitoring device of claim 5 wherein said sensing means is adjustably connected to said transmission member so as to vary the relative position between said sensing means and said transmission member to adjust said predetermined limit at which said tripping device generates said tripping signal.

7. The pressure monitoring device of claim 5 wherein said housing is adapted to receive a flexible fluid line within said housing when said pressure transmission means is operating in said first mode, and wherein said sensing means is adapted to move within said housing in response to changes in the pressure of the fluid in said flexible fluid line to in turn move said transmission member relative to said housing.

8. The pressure monitoring device of claim 7 further including pressure indication means adapted to be connected to said flexible fluid line to visually indicate the pressure of the fluid within said line, and wherein said sensing means is adjustable with respect to said transmission member, movement of said sensing member relative to said transmission member resulting in adjustment of said predetermined limit, and said indication means providing a visual indication related to said predetermined limit set by the positioning of said sensing means relative to said transmission member.

9. The pressure monitoring device of claim 5 wherein said coupling means comprises spring means having a first spring position and a second spring position, said spring means being interposed between and operatively associated with said transmission member and said tripping device, said spring means when in said first spring position directly transmitting movement of said transmission member to said tripping switch, and said spring means when in said second spring position biasing said tripping switch towards said second position independent of the position of of said transmission member.

24. The pressure monitoring device of claim 1 wherein said coupling means is positionable in said second position when said pressure transmission means is operable in said second mode so that said tripping device is hindered from generating a tripping signal.

10. A pressure monitoring and tripping device for monitoring the pressure of a fluid and for generating a signal when the pressure passes a predetermined value, said pressure monitoring and tripping device comprising:

pressure transmission means adapted to be responsive to the pressure of the fluid being monitored;

a tripping device having switch means movable between a first switch position and a second switch position, and signal generating means for generating a signal when said switch means is in said first switch position; and

spring means having a first spring position and a second spring position, said spring means being interposed between said pressure transmission means and said switch means, said spring means when in said first spring position directly coupling said pressure transmission means to said switch means so that said switch means is movable between said first and second switch positions in response to the pressure of the fluid being monitored such that said switch means moves to said first switch position when the pressure of the fluid being monitored passes the predetermined value, and said spring means when in said second spring position biasing said switch means towards said second switch position, independent of the pressure sensed by said pressure transmission means so that said switch means is hindered from moving towards said first switch position.

11. The pressure monitoring device of claim 10 further including a housing in which said pressure transmission means is supported for relative movement with respect thereto;

and wherein said pressure transmission means comprises sensing means within said housing for sensing the pressure of the fluid, and a transmission member extending through said housing and operatively connected to said sensing means for movement with respect to said housing in response to the pressure sensed by said sensing means, the relative position of said transmission member with respect to said housing being indicative of the pressure sensed by said sensing means.

12. The pressure monitoring device of claim 11 wherein said sensing means is adjustably connected to said transmission member so as to vary the relative position between said sensing means and said transmission member to adjust the predetermined pressure value at which said switch means moves to said first switch position.

13. The pressure monitoring device of claim 12 wherein said sensing means is a sensing element threadably connected to the end of said transmission member within said housing, the longitudinal position of said sensing element relative to said transmission member being indicative of the predetermined pressure value at which said switch means moves into said first switch position when said spring means is in said first position.

14. The pressure monitoring device of claim 10 wherein said pressure transmission means comprises a pressure transmission member acting against said switch means independent of any biasing force exerted by said spring means when said spring means is in said first position.

15. The pressure monitoring device of claim 14 wherein said spring means comprises a plate spring and spring holding means for fixably holding the ends of said plate spring at a distance apart from one another less than the length of said plate spring.

16. The pressure monitoring device of claim 15 wherein said spring holding means is carried by said pressure transmission member and wherein said plate spring carries a pressure transmission element for engaging said switch means to vary the position of said switch means in response to changes in the position of said pressure element, said pressure transmission element being in contact with said pressure transmission member when said plate spring is in said first position so that said pressure transmission member and said pressure transmission element move together in response to changes in the pressure of the fluid being monitored.

17. The pressure monitoring device of claim 16 wherein said pressure sensing element is separated from direct contact with said pressure transmission member when said plate spring is in said second position.

18. The pressure monitoring device of claim 17 wherein said plate spring when in said first position is bowed toward said pressure transmission member so that said pressure transmission element contacts said pressure transmission member, and wherein said plate spring is bowed away from said pressure transmission member when in said second position so that said pressure transmission element is separated from said pressure transmission member.

19. The pressure monitoring device of claim 17 wherein said tripping device comprises a microswitch having a spring loaded actuating element, said spring loaded actuating element being in an extended when in said first switch position and being in a retracted when in said second switch position.

20. The pressure monitoring device of claim 19 further including a housing for supporting said pressure transmission member for relative movement with respect thereto;

wherein said pressure transmission means further includes sensing means within said housing operatively connected to said pressure transmission member for sensing the pressure of the fluid being monitored and for moving said pressure transmission member in response thereto; and

further including support means for supporting said microswitch in fixed relationship to said housing so that said pressure transmission element carried by said plate spring depresses said spring loaded actuating element of said microswitch into said second switch position when the pressure of the fluid being monitored is greater than said predetermined pressure value, and so that said pressure transmission element permits said spring loaded element to move into said first switch position when the pressure falls below said predetermined pressure value.

21. The pressure monitoring device of claim 20 wherein the position of said sensing means relative to said pressure transmission member is adjustable so that the predetermined pressure at which said spring loaded actuating element will move into said first switch position is adjustable.

22. The pressure monitoring device of claim 21 further including gauge means in fluid communication with the fluid to be monitored to aid in adjustment of said sensing means to adjust said predetermined pressure limit.

23. The pressure monitoring device of claim 10 wherein said spring means comprises a plate spring and spring holding means for fixably holding the ends of said plate spring at a distance apart from one another less than the length of said plate spring.