Fluid handling – Line condition change responsive valves – Pilot or servo controlled
Reexamination Certificate
1999-04-29
2001-01-16
Huson, Gregory L. (Department: 3753)
Fluid handling
Line condition change responsive valves
Pilot or servo controlled
C137S505120, C137S492000, C137S614210
Reexamination Certificate
active
06173735
ABSTRACT:
BACKGROUND ART
1. Field of the Invention
The present invention relates generally to regulator valves useful in creating and maintaining a selected pressure in a gas pipe or conduit. More specifically, the present invention relates to a regulator capable of creating and maintaining two pressure reductions in series with each other within a single regulator body.
2. Description of Related Art
Regulator valves for controlling the pressure of a gas pipe or conduit are well known in the art. There are many ways to regulate the flow rate to equal demand and thus maintain a constant pressure of the gas pipe or conduit independent of inlet pressure and/or load fluctuations. In some applications, several gas-flow regulators are connected in series such that if one regulator fails to control outlet pressure the second regulator takes over control. Most regulator valves include a mechanism, such as a cage or throttle plate, for restricting the flow of the gas stream and creating the pressure drop. These cages and throttle plates usually include a variety of holes or slots through which a selected portion of the gas stream is allowed to flow by altering the position of the diaphragm. Many of these regulator valves include additional control valves for actuating the main gas-flow regulator valve.
As the technology advanced, gas-flow regulator valves began to include control valves having one or more additional pilot amplifier valves with closed-loop feedback capabilities. These pilot valves generally contained a sensing pressure chamber and an actuator that positions the pilot valve. The pressure inputs to these pilot valves could be connected to a loading chamber that is in fluid communication with the throttling diaphragm of the main regulator such that inlet pressure can be applied to the diaphragm to position the diaphragm correctly. In addition, it was not uncommon to connect more than one pilot valve to a single flow regulator. The control pressures within these pilot valves could be derived from the pressure of the gas stream upstream of the main regulator, (back pressure regulator), or the pressure of the gas stream downstream of a throttling regulator.
Despite these advances in the art, there continues to be a need for improved regulator construction and control system in order to increase efficiency, provide improved reliability, and decrease operational noise, while decreasing the cost of regulator maintenance.
BRIEF SUMMARY OF THE INVENTION
There is a need for a regulator in which two two-stage pressure drops can be performed, in series, within a single gas-flow regulator. There is also a need for a single-port regulator in which two pressure drops can be performed, in series, within the single-port gas-flow regulator. There is also a need for an improved circular throttle plate that has radial arrangements of flow apertures. There is also a need for a flexible, circular flat-bottom diaphragm of non-uniform thickness that can be configured such that the diaphragm lifts in one area before it lifts in another area for improved low-flow control and high turn-down performance.
It is an object of the present invention to provide a two-port regulator comprising an inlet chamber, a first-reduction diaphragm-controlled port chamber, a second-reduction central transfer chamber, a third-reduction diaphragm-controlled port chamber, and a fourth-reduction outlet chamber, wherein the inlet chamber and the outlet chamber both completely circumscribe the central transfer chamber. The regulator has a first throttle plate located between the inlet chamber and the first-reduction diaphragm-controlled port chamber, and between the first-reduction diaphragm-controlled port chamber and the second-reduction central transfer chamber. The regulator also has a second throttle plate located between the second-reduction central transfer chamber and the third-reduction diaphragm-controlled port chamber, and between the third-reduction diaphragm-controlled port chamber and the fourth-reduction outlet chamber. The configuration of the inlet chamber, outlet chamber, and first and second throttle plates, and the multi-stage pressure-reduction technique is designed to substantially reduce operational noise of the regulator by minimizing unstable turbulent flow within the valve body.
It is another object of the present invention to provide a single-port regulator comprising an inlet chamber, a first-reduction diaphragm-controlled port chamber, and a second-reduction outlet chamber. A single throttle plate is disposed between the inlet chamber and the first-reduction diaphragm-controlled port chamber, and between the first-reduction diaphragm-controlled port chamber and the second-reduction outlet chamber. The second-reduction outlet chamber completely circumscribes the inlet chamber adjacent to the throttle plate. The configuration of the inlet chamber, the second-reduction outlet chamber, and the throttle plate is designed to substantially reduce operational noise of the regulator by minimizing unstable turbulent flow within the valve body through the use of drilled ports that straighten the flow stream into the second-reduction outlet chamber.
It is another object of the present invention to provide a throttle plate for use in a regulator, the throttle plate having an outer ring arrangement of drilled flow apertures with three different diameters, increasing in diameter with greater distance from the center of the port and a second inner arrangement of flow apertures in the form of slots with varying lengths but constant widths. In this manner, because the diaphragm is designed to open in the center first, the smaller diameter drilled apertures in the outer ring arrangement of drilled apertures, are opened before the larger diameter drilled apertures in the outer ring arrangement of drilled apertures, thereby insuring stability at low-flow conditions, while providing high capacity at maximum diaphragm lift. The throttle plate is configured such that the gas stream flows radially parallel to the throttle plate either from a center to a periphery for the two-port outlet throttle plate, or from the periphery to the center for the two-port inlet throttle plate.
It is another object of the present invention to provide a flexible circular diaphragm of non-uniform thickness for use in a gas-flow regulator, the flexible diaphragm having a flat front surface for sealing flow apertures in a throttle plate, and an opposing rear surface having a central concave portion that allows the diaphragm to unseal the flow apertures from the center portion of the throttle plate before unsealing the flow apertures at the periphery of the throttle plate. For throttle plates with an outer ring arrangement of flow apertures with multiple diameters, increasing in diameter with greater distance from the center of a port; as the flexible diaphragm opens the innermost ring of flow apertures, while keeping other rings of flow apertures closed, an incremental decrease of a loading pressure on the flexible diaphragm will yield a relatively small incremental increase in flow rate, compared with the same incremental decrease of the loading pressure as the remaining flow apertures, having increasingly larger diameters, are opened. The number of rings of flow apertures in the outer ring arrangement is limited only by the port area available and aperture diameter. The diaphragm lift is controlled by a bias spring disposed within a loading chamber, and a loading chamber pressure differential. The bias spring and the loading chamber pressure allow a higher inlet pressure to lift the flexible diaphragm in proportion to the differential pressure across the flexible diaphragm and the bias spring rate. The loading chamber pressure is controlled remotely by a pilot amplifier valve that lowers the loading pressure, thereby allowing the flexible diaphragm to open, and increase flow, if required.
It is another object of the present invention to provide a control system for controlling a gas-flow regulator, the control system comprising at least one multi-
Glasscock Mick
Krogue John A.
McKibbin Philip J.
Perry, Jr. Marney Dunman
Gunter, Jr. Charles D.
Huson Gregory L.
Krishnamurthy Ramesh
Perry Equipment Corporation
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