1. Field of the Invention
The present invention relates to a pressure controller for a pressure regulator and more specifically to a pressure controller that includes pressure source independent of the process fluid and controls the regulator based on pressure sensed remotely from the regulator.
2. Related Art
In systems for supplying liquid or gas to a point for use from a source which is subject to variable conditions, a pressure regulator is often utilized. The regulator functions to maintain a constant pressure in the fluid despite variations in pressure from the supply.
It has been known to install a pressure transducer downstream of a regulator to read downstream pressure and transfer the reading to an electronic controller which compares the signal with a predetermined setting. The electronic controller sends an electrical signal to a converter which transforms the electrical signal into a pneumatic signal and increases or decreases pressure in the regulator to adjust downstream pressure.
Efforts of others include the following:
Bloom, U.S. Pat. No. 2,339,753, discloses a liquid control apparatus comprising a single unit that regulates pressure of fluid flowing through it in one direction, and utilizes the pressure of the fluid in the other direction, in a separate chamber, to control the regulator. The invention is related primarily to regulators used in industrial furnace installations, such as, those fired with tar or heavy oil.
Katchka, U.S. Pat. No. 3,525,355, discloses a flow control device that can be used in connection with, for example, a fuel control apparatus for a water heater control system. The device includes an inlet, an outlet and a main valve of the pressure-to-close type interposed therebetween. The valve includes a flexible diaphragm and a coil spring. On the back side of the diaphragm is an operating pressure chamber. An external bleed path communicates with the inlet passage. The external bleed path includes a conduit, a thermostatic valve and another conduit that reenters the casing at a passage which eventually leads to the outlet through a pressure chamber and a passage with a flow restrictor therein. The internal bleed path communicates with the inlet through a passage having a porting which communicates with the operating pressure chamber. The internal bleed path also leads to a bleed path valve having a valve seat, a spring and a valve member. The passage leads from the bleed path valve to a regulating valve which includes a valve seat, a valve member and a flexible diaphragm.
Kakegawa, U.S. Pat. No. 3,805,823, discloses a pressure regulator having a main regulator and a pilot regulator. The device includes two chambers in a main regulator divided by a main diaphragm. Flow of fluid passing through the regulator is controlled by the pilot regulator which communicates at one end with the downstream side and at the other end with the upstream side. The pressure differential between the upstream side and the downstream side serves to vary the position of the main diaphragm thereby adjusting the valve to maintain fluid pressure on the low pressure side constant.
Modes, U.S. Pat. No. 4,157,159, discloses a self adjusting fluid flow regulator for use in fluid handling systems capable of maintaining a constant flow rate. The flow regulator may be utilized within an air distribution system such as that which supplies air through ducts to various rooms or portions of an enclosure. The system includes a pressurized air source which supplies air flow through a duct network to various terminal ports.
Risk, U.S. Pat. No. 4,000,754, discloses an automatic control valve for a fluid system such as for a hydraulic elevator system. The device includes a main valve body with first and second chambers interconnected by a port. An adjustable valve restricts the flow of fluid through the port. The adjustable valve is controlled by a fluid responsive valve actuator means. A first bypass conduit interconnects the first chamber and the valve actuator and controls the rate of fluid flow from the first chamber to the valve actuator. A second bypass conduit interconnects the second chamber with the valve actuator. A regulator connected across the first and second bypass conduits and responsive to the rate of fluid flow through the valve, is actuated by a fluid flow rate greater than a pre-determined rate to restrict the second bypass conduit thereby developing a pressure build up in the valve actuator and enabling the valve actuator to close the valves until the pressure unbalance is removed.
Johnson, U.S. Pat. No. 4,083,375, discloses a pilot regulator for pressure regulation servo-control of a valve in a compressible fluid system. The regulator includes a restrictor for supplying fluid from the main valve inlet to a control chamber.
McNeely, U.S. Pat. No. 5,027,852, discloses a safety relief system for a pressure vessel having a safety relief valve in a main flow line from the pressure vessel. The pilot valve includes a separate auxiliary source of high pressure fluid for operating the pilot valve.
What would be desirable, but has not heretofore been developed, is a pressure controller which functions without electronics which senses pressure at a point of regulation and based on said pressure utilizes an independent pressure source to provide a control pressure to a pressure regulator.
It is an object of the present invention to provide a pressure controller for a pressure regulator.
It is another object of the present invention to provide a pressure controller for controlling a pressure regulator which pressure controller does not have electronic components.
It is even another object of the present invention to provide a pressure controller which uses a pressure source, independent of the process fluid, for control pressure.
It is a further object of the present invention to provide a pressure controller for a pressure regulator which uses compressed air to control pressure in the pressure regulator.
It is a further object of the present invention to provide a pressure controller which provides compressed air to a pressure regulator based on process fluid pressure being regulated by the pressure regulator.
It is still a further object of the present invention to provide a pressure controller that uses compressed air wherein compressed air is directed to a pressure regulator or to atmosphere or to both based on the pressure of the process fluid being regulated by the pressure regulator.
The present invention relates to a pressure controller for controlling a pressure regulator to deliver process fluid at a regulated pressure from a variable pressure supply. The pressure controller includes a control pressure source independent of the process fluid, such as compressed air, which enters the controller through a restriction. The compressed air passes through the controller to the regulator where it exerts pressure on the pressure regulator. The controller is interconnected with the process fluid line and senses pressure in a diaphragm chamber of the controller. The pressure on the diaphragm is opposed by a bias such as a spring. The diaphragm is interconnected with a valve. The bias tends to move the valve to a closed position. Pressure on the diaphragm tends to move the valve to an open position. The bias means is adjustable. As pressure in the diaphragm chamber pressure rises, corresponding to a rise in pressure of the process fluid pressure, the diaphragm is moved to open the valve to allow the flow of the control pressure through the valve to a drain, such as atmosphere. If the regulated pressure falls below a set point, the valve closes and the control pressure is not drained or vented to atmosphere, but flows directly to the regulator to increase pressure on the regulator to increase the pressure of the process fluid. At the set pressure the valve is partially open limiting air flow to atmosphere, maintaining constant pressure to the regulator, so the force of the bias is equal to the force of the process fluid on the diaphragm. The design of the invention provides feedback to the regulator based on downstream pressure sensed by the controller without the need for electronics.