Valve control apparatus and method
AssigneePhillips Petroleum Company
InventorHadwen A. Clayton
Life of this patent
Estimating the term…
Abstract
An apparatus and method for controlling a fluid pressure actuated valve are provided whereby the valve inlet pressure and valve outlet pressure are applied to control and limit the valve outlet pressure and to substantially reduce the fluid pressure applied to the valve actuating means when the valve inlet pressure is below a preselected safe value.
Claims10
Apparatus for controlling the flow of fluid through a main conduit means, said apparatus comprising:
- a valve means for controlling flow through said main conduit, said valve means comprising
- an upstream inlet portion,
- a downstream outlet portion,
- a valve element adapted to vary the restriction to flow from said upstream inlet portion to said downstream outlet portion, and
- pilot pressure inlet means for applying fluid pressure to said valve element to exert a closing force on said valve element;
- first conduit means, in fluid communication with said upstream inlet portion of said valve means, for providing a source of fluid pressure responsive to the fluid pressure within said upstream inlet portion;
- second conduit means, in fluid communication with said downstream outlet portion of said valve means, for providing a source of fluid pressure responsive to the fluid pressure within said downstream outlet portion;
- flow restriction means for providing a predetermined degree of communication between said first conduit means and a third conduit means;
- first pilot valve means for controlling fluid communication between said second conduit means and said third conduit means in response to the fluid pressure within said second conduit means;
- second pilot valve means for controlling fluid communication between said third conduit means and said pilot pressure inlet means in response to the fluid pressure within said first conduit means;
- and
- third pilot valve means for controlling fluid communication between said pilot pressure inlet means and a low fluid pressure source in response to the fluid pressure within said first conduit means, said low fluid pressure source having a fluid pressure which is less than the fluid pressure within said second conduit means.
A method for operating a valve means having an upstream inlet, a downstream outlet, and a fluid-actuated closure mechanism associated therewith to control the flow of fluid through said valve means, said method comprising:
- establishing a first fluid pressure signal responsive to the fluid pressure within said upstream inlet of said valve means;
- establishing a second fluid pressure signal responsive to the fluid pressure within said downstream outlet of said valve means;
- automatically applying said first fluid pressure signal to said closure mechanism when said second fluid pressure signal exceeds a preselected first pressure value;
- automatically applying said second fluid pressure signal to said closure mechanism when said first fluid pressure signal is within a preselected range between said first pressure value and a preselected second pressure value, said second pressure value being lower than said first pressure value;
- and
- automatically reducing the pressure applied to said closure mechanism to a value lower than said second fluid pressure signal when said first fluid pressure signal is lower than a preselected third pressure value, said third pressure value being lower than said second pressure value.
Dependencies are inferred from the claim text.