CA1168940A - Pneumatic pressure transmitter - Google Patents
Pneumatic pressure transmitterInfo
- Publication number
- CA1168940A CA1168940A CA000420568A CA420568A CA1168940A CA 1168940 A CA1168940 A CA 1168940A CA 000420568 A CA000420568 A CA 000420568A CA 420568 A CA420568 A CA 420568A CA 1168940 A CA1168940 A CA 1168940A
- Authority
- CA
- Canada
- Prior art keywords
- inlet
- exhaust
- spring
- diaphragm
- pilot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D16/00—Control of fluid pressure
- G05D16/20—Control of fluid pressure characterised by the use of electric means
- G05D16/2086—Control of fluid pressure characterised by the use of electric means without direct action of electric energy on the controlling means
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D16/00—Control of fluid pressure
- G05D16/04—Control of fluid pressure without auxiliary power
- G05D16/06—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule
- G05D16/063—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane
- G05D16/0675—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane the membrane acting on the obturator through a lever
- G05D16/0683—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane the membrane acting on the obturator through a lever using a spring-loaded membrane
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
- Control Of Fluid Pressure (AREA)
Abstract
PNEUMATIC PRESSURE TRANSMITTER
Abstract A pneumatic pressure transmitter for converting electrical signals into pressure, comprising a lever, an auxilliary spring, two separate pilots for inlet and exaust valves, a loading spring and a stepped motor inside the knob. The pneumatic pressure transmitter can work in the manual or automatic modes. The same regulating mechanism can be used for control valve positioners, pressure regulators, pneumatic relays and others.
Abstract A pneumatic pressure transmitter for converting electrical signals into pressure, comprising a lever, an auxilliary spring, two separate pilots for inlet and exaust valves, a loading spring and a stepped motor inside the knob. The pneumatic pressure transmitter can work in the manual or automatic modes. The same regulating mechanism can be used for control valve positioners, pressure regulators, pneumatic relays and others.
Description
Specification 1. This invention pertains to the field of instrumentation and in particular for use with pneumatically powered control valves. Presently available transmitters (transducers) are complicated and expensive. Simple regulators cannot be used because of the big force that is necessary to operate them znd structurally complicated alterations must be made.
The object of the present invention ;s to alleviate the problems mentioned above by providing a new regulating mecha-nism which closes the inlet valve agaist the flow and uses the auxilliary spring to compensate the force of supply pres-sure. The pneumatic pressure transmitter has a fast response, a small "dead zone", a small hysteresis and low air consumption.
It is simple to manufacture and service. The low force neces-sary to operate the pneumatic pressure transmitter allows for the installation of a stepped motor and for the use of the pneumatic pressure transmitter in a manual or automated control.
~ ., .
1 ~8940
The object of the present invention ;s to alleviate the problems mentioned above by providing a new regulating mecha-nism which closes the inlet valve agaist the flow and uses the auxilliary spring to compensate the force of supply pres-sure. The pneumatic pressure transmitter has a fast response, a small "dead zone", a small hysteresis and low air consumption.
It is simple to manufacture and service. The low force neces-sary to operate the pneumatic pressure transmitter allows for the installation of a stepped motor and for the use of the pneumatic pressure transmitter in a manual or automated control.
~ ., .
1 ~8940
2. In ths drawings which illustrate embodiment of the invention t Fig, 1 is an elevation showing the pneumatic pressure transmitter, Fig. 2 is a crosY section taken along the line I-I
of the Fi~, 1,
of the Fi~, 1,
3. As it is illustrated in the drawing, a frame of the pneumatic pressure transmitter 6, 13, 21 (See Fig, 1) forms a control pressure chamber 15 and a loading spring chamber 25, separated by a diaphragm 26 with an exhaust valve 9 in the centre, The fluid flows through an inlet connector 7 and an inlet valve 1 into the control pressure chamber and to an outlet connector 14, The control pressure chamber houses a regulating mechanism, comprising an inlet pilot 2, an exhaust pilot`lO, a lever 8 with a pivot 5 fixed at the frame and an auxilliary spring 12. Guides 3, 4, 11 and 26 provide a travel cantrol for the pilots.~ The pilots, the lever and the auxilliary sprin~ interact in such a way that the auxilliary spring pushes the exaust pilot and one arm of the lever, while the other arm of` the lever pushes the inlet pllot. The auxil-liary spring has to be sufficiently strong to keep both valves clo~ed when the control pressure is counterbalan~ed by the force of the loading spring, Surplus or lack of pressure moves the diaphragm and opens the exhaust or inlet valve, To compress the loading spring a threaded shaft 22 and a sliding nut are used. Such a combination with a bearing 17 prevents the threaded shaft from axial mo~ement.
A stator of the variable reluctance type stepped motor 18 with windings 16 is fixed at the frame. A rotor 2 is rigi~ly connected with a knob 19 to the threaded shaft 22 and can be turned manually or electrically to change the control pressure.
A stator of the variable reluctance type stepped motor 18 with windings 16 is fixed at the frame. A rotor 2 is rigi~ly connected with a knob 19 to the threaded shaft 22 and can be turned manually or electrically to change the control pressure.
Claims (2)
PROPERTY OR PRIVILEGE ARE DEFINED AS FOLLOWS:
1. A pneumatic pressure transmitter comprising:
a frame with a control pressure chamber, a loading spring chamber and a diaphragm which separates said chambers:
an exhaust valve mounted in the centre of said diaphragm;
an inlet valve;
an inlet pilot (2) and an exhaust pilot (10) means for closing said inlet and exhaust valves;
a lever with a pivot fixed at the frame;
an auxilliary spring and a loading spring means for putting a reference pressure on the diaphragm;
said inlet and exhaust pilots, lever and auxilliary spring are housed inside the control pressure chamber and interact in such a way that the auxilliary spring pushes the exhaust pilot and one arm of the lever while the other arm of said lever pushes the inlet pilot with a force sufficient to keep the inlet and exhaust valves closed when the pressure in the control pressure chamber is counterbalanced by the force of the loading spring: whereby a surplus pressure in the control pressure chamber moves the diaphragm and opens the exhaust valve; lack of pressure in said chamber moves the diaphragm under a force of the loading spring in the opposite direction, pushes the exhaust pilot, compresses the auxilliary spring and opens the inlet valve.
a frame with a control pressure chamber, a loading spring chamber and a diaphragm which separates said chambers:
an exhaust valve mounted in the centre of said diaphragm;
an inlet valve;
an inlet pilot (2) and an exhaust pilot (10) means for closing said inlet and exhaust valves;
a lever with a pivot fixed at the frame;
an auxilliary spring and a loading spring means for putting a reference pressure on the diaphragm;
said inlet and exhaust pilots, lever and auxilliary spring are housed inside the control pressure chamber and interact in such a way that the auxilliary spring pushes the exhaust pilot and one arm of the lever while the other arm of said lever pushes the inlet pilot with a force sufficient to keep the inlet and exhaust valves closed when the pressure in the control pressure chamber is counterbalanced by the force of the loading spring: whereby a surplus pressure in the control pressure chamber moves the diaphragm and opens the exhaust valve; lack of pressure in said chamber moves the diaphragm under a force of the loading spring in the opposite direction, pushes the exhaust pilot, compresses the auxilliary spring and opens the inlet valve.
2. A pneumatic pressure transmitter as defined in claim 1 further comprising:
a threaded shaft and a sliding nut means for compressing the loading spring by rotating said threaded shaft;
a stator of the stepped motor fixed at the frame a rotor of the stepped motor mounted outside the stator and rigidly fixed with the knob and the threaded shaft means for rotating said shaft;
whereby the treaded shaft can by rotated manually by the knob or electrically by the stepped motor.
a threaded shaft and a sliding nut means for compressing the loading spring by rotating said threaded shaft;
a stator of the stepped motor fixed at the frame a rotor of the stepped motor mounted outside the stator and rigidly fixed with the knob and the threaded shaft means for rotating said shaft;
whereby the treaded shaft can by rotated manually by the knob or electrically by the stepped motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000420568A CA1168940A (en) | 1983-01-31 | 1983-01-31 | Pneumatic pressure transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000420568A CA1168940A (en) | 1983-01-31 | 1983-01-31 | Pneumatic pressure transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1168940A true CA1168940A (en) | 1984-06-12 |
Family
ID=4124455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000420568A Expired CA1168940A (en) | 1983-01-31 | 1983-01-31 | Pneumatic pressure transmitter |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1168940A (en) |
-
1983
- 1983-01-31 CA CA000420568A patent/CA1168940A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |