# US 4,936,340 A · Pressure regulator

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- Number: US 4,936,340 A
- Document ID: US4936340A
- Status: Granted
- Kind: A
- Application number: 07/369,212
- Filed: 1989-06-21
- Granted: 1990-06-26
- Earliest claimed: 1989-06-21
- Assignees: Coretest Systems, Inc.
- Inventors: Jared M. Potter; Douglas N. Sweet
- Web page: https://patentgrep.com/patent/US4936340A

## CPC

- G05D 16/202: {actuated by an electric motor}
- Y10T 137/7761: Electrically actuated valve
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A pressure control assembly is disclosed. The assembly includes a pressure transducer for detecting upstream pressure. A diaphragm is used to regulate flow through the assembly, and is forced into a closed position by pressure from a fluid column. The pressure on the fluid column is controlled by a piston driven by a step motor. The step motor is activated in response to signals from the pressure transducer.

## Claims

### Claim 1

A valve for controlling pressure in a flow line comprising:
(a) means for detecting pressure in said flow line;
(b) a diaphragm in contact with said flow line; and
(c) means, responsive to said means for detecting, for increasing a pressure in a liquid filled region, said liquid filled region in contact with and urging said diaphragm into said flow line to restrict flow therein, said means for increasing pressure further comprises:
(i) an electric motor driven pump means in contact with said liquid filled region; and
(ii) a controller for receiving a signal from said means for detecting pressure and activating said motor in response thereto.

### Claim 2 (depends on 1)

Apparatus as recited in claim 1, wherein said liquid filled region is an oil filled region.

### Claim 3 (depends on 1)

A valve as recited in claim 1, wherein said means for detecting pressure in said flow line is a pressure transducer.

### Claim 4 (depends on 1)

Apparatus as recited in claim 1, wherein said electric motor driven pump means further comprises:
(a) a step motor; and
(b) a piston connected to said step motor, said piston driveable by said motor from a first position in said liquid filled region to a second position in said liquid filled region.

### Claim 5 (depends on 1)

Apparatus as recited in claim 1, wherein said controller further comprises:
(a) means for supplying a reference voltage;
(b) means for comparing a voltage from said means for detecting pressure to said reference voltage; and
(c) a driver adapted to activate said motor in response to an output from said means for comparing.

### Claim 6 (depends on 5)

Apparatus as recited in claim 5, wherein said output from said means for comparing is converted to a pulse signal, said pulse signal having a frequency related to said output from said means for comparing, wherein said pulse signal is used to provide an input to said driver.

### Claim 7

A valve for controlling pressure in a flow line comprising:
(a) means for detecting pressure in said flow line;
(b) a diaphragm in contact with said flow line;
(c) means, responsive to said means for detecting, for increasing a pressure in a liquid filled region, said liquid filled region in contact with and urging said diaphragm into said flow line to restrict flow therein, said means for increasing pressure further comprising:
(i) an electric motor driven pump means in contact with said liquid filled region; and
(ii) a controller for receiving a signal from said means for detecting pressure and activating said motor in responsive thereto, said controller further comprising:
means for supplying a reference voltage;
means for comparing a voltage from said means for detecting pressure to said reference voltage; and
a driver adapted to activate said motor in response to an output from said means for comparing;
(d) means for detecting a pressure in said liquid filled region;
(e) means for comparing a second reference voltage to a voltage representative of said pressure in said liquid filled region to provide a restriction output; and
(f) means for restricting movement of said piston based on said restriction output.

### Claim 8 (depends on 4)

Apparatus as recited in claim 4, wherein said step motor further comprises:
(a) a ball screw and ball nut on a shaft of said motor;
(b) a guide bushing attached to said ball nut; and
(c) a spring for urging said piston against said bushing.

### Claim 9 (depends on 1)

Apparatus as recited in claim 1, wherein said controller further comprises means for providing a binary signal to disable said control means.

### Claim 10 (depends on 1)

Apparatus as recited in claim 1, wherein said controller further comprises means for a user to activate said pump in a desired direction.

### Claim 11

Apparatus for regulating pressure in a flow line comprising:
(a) an inlet flow line, said line, said inlet flow line having a pressure transducer therein;
(b) a vent flow line;
(c) a diaphragm between said inlet flow line and said discharge flow line for restricting flow from said inlet flow line to said vent line;
(d) a liquid filled region adjacent said diaphragm opposite said flow lines;
(e) a piston in said liquid filled region;
(f) a step motor driven ball screw and ball nut for urging said piston into said liquid filled region;
(g) a spring for urging said piston out of said liquid filled region;
(h) a control means, said control means further comprising:
(i) means for generating a reference voltage;
(ii) means for comparing said reference voltage to a voltage from said pressure transducer; and
(iii) means for activating said motor in responsive to said means for comparing; and
(i) a pressure transducer in said liquid filled region, said transducer monitoring pressure in said liquid filled region for overpressure or underpressure.