Diaphragm valve with electronic pressure detection
A flush valve for a waste water system comprises a valve including a fluid inlet, a fluid outlet and a main valve element adapted for movement to allow fluid flow between the fluid inlet and the fluid outlet based on a pressure differential across a portion of the main valve element. The valve also includes a vent system comprising a control chamber in flow communication with the fluid inlet of the valve and a vent outlet in flow communication with the fluid outlet of the valve, and a solenoid for venting fluid venting fluid from the control chamber to the fluid outlet. A pressure sensor, such as an electronic pressure transducer, senses the fluid pressure of fluid within the vent system. When a predetermined pressure threshold is reached or exceeded, the solenoid can be energized to release fluid from the control chamber.
1. A flush valve for a waste water system, comprising:
a valve body comprising a fluid inlet and a fluid outlet and a main valve element extending between the fluid inlet and the fluid outlet, the main valve element adapted for movement to allow fluid flow between the fluid inlet and the fluid outlet based on a pressure differential across a portion of the main valve element;
a vent system comprising a control chamber in flow communication with the fluid inlet of the valve body and a vent outlet in flow communication with the fluid outlet of the valve body;
a solenoid having a piston operable in a core tube in flow communication with the control chamber and configured to open to establish flow communication between the control chamber and the vent outlet thereby venting fluid from the control chamber to the fluid outlet and establishing a pressure differential across a portion of the main valve element and permitting the main valve element to open for fluid flow between the fluid inlet and fluid outlet of the valve body, and to close to prevent fluid communication between the control chamber and the vent outlet to close the main valve element; and
a pressure sensor adapted to sense the fluid pressure of fluid within the core tube, wherein the solenoid is controlled to vent the control chamber for a period of time short enough to reduce the fluid pressure within the control chamber without opening the main valve element when the pressure within the core tube exceeds a predetermined pressure threshold.
2. The flush valve according to claim 1 , wherein at least a portion of the valve body is constructed of a plastic material.
3. The flush valve according to claim 1 , wherein the vent system further comprises a vent chamber in flow communication with the control chamber through a vent inlet passage extending between the control chamber and the vent chamber, and wherein the vent outlet is in flow communication with the vent chamber.
4. The flush valve according to claim 1 , wherein the pressure sensor comprises a pressure transducer.
5. The flush valve according to claim 4 , wherein the pressure transducer is connected to a control board comprising a pressure transducer control and a microprocessor.
6. The flush valve according to claim 5 , wherein the control board is located on the solenoid.
7. The flush valve according to claim 5 , wherein the pressure transducer control includes a voltage amplifier.
8. The flush valve according to claim 1 , wherein the core tube is in flow communication with a vent chamber which is in flow communication with the control chamber.
9. The flush valve according to claim 8 , including an actuating coil around at least a portion of the core tube.
10. The flush valve according to claim 9 , wherein the actuating coil comprises a first coil section and a second coil section.
11. A method of controlling a flush valve, comprising:
providing a flush valve as claimed in claim 1 ;
defining a pressure threshold corresponding to a relief pressure for the valve;
sensing the fluid pressure of fluid within the valve;
activating the solenoid when the fluid pressure within the valve meets or exceeds the defined pressure threshold.
12. A method of regulating pressure within a flush valve in a waste water system, comprising:
providing a valve body including a fluid inlet and a fluid outlet and a main valve element adapted for movement to allow fluid flow between the fluid inlet and the fluid outlet based on a pressure differential across a portion of the main valve element, the valve comprising a vent system for venting fluid from the fluid inlet to the fluid outlet to establish a pressure differential across a portion of the main valve element to cause the main valve element to open, the vent system comprising a control chamber in flow communication with the fluid inlet of the valve body, a vent outlet in flow communication with the fluid outlet of the valve body, and an electronically operated solenoid having a piston configured to open and close the vent outlet upon energization thereof;
sensing the fluid pressure of fluid within the vent system of the valve;
venting fluid within the vent system of the valve from the fluid inlet to the fluid outlet when the fluid pressure within the vent system exceeds a predetermined pressure threshold corresponding to a relief pressure for the valve, wherein the venting step comprises energizing the solenoid to open the vent outlet to establish flow communication between the control chamber and the vent outlet to vent fluid from the control chamber to the fluid outlet; and
energizing the solenoid for a period of time below that required to vent a volume of fluid from the vent chamber associated with establishing a pressure differential across a portion of the main valve element which would cause the main valve element to open, thereby reducing the fluid pressure within the vent chamber without opening the main valve element.