Flow system with pressure level interlock control apparatus
First Claim
1. A flow control system having a pressure source means and a line valve means in a flow line to establish a pressurized flow through the line, said pressure source means being operable to establish a selected line pumping pressure level, comprising a controller for selectively operating said valve means to establish a flow cycle, said controller having means operating said valve means in response to an input signal generated independently of said pressure level and including a controllable switch means for actuating the controller, and interlock limit means to sense the pressure in the line with the valve closed and coupled to the switch means to prevent operation thereof and thereby actuation of the line valve means in response to a preselected line pressure less than said selected line pumping pressure level.
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Accused Products
Abstract
A vacuum operated sewage system includes a static pressure sensor establishing a trigger signal at a selected first level in a standpipe. The sensor is connected upstream of a discharge control valve and actuates a trigger and timer controller at the selected sensed pressure to establish low for a predetermined period. A suitable time delay capacitor in the controller prevents transient signal actuation. A system pressure interlock senses the vacuum level of the system to disable the timer controller if system pressure is below a selected level. The interlock may include a pressure level control valve connected to bleed the capacitor and disable the timer controller. A system pressure sensing valve in parallel with the level control valve decouples the latter as long as the system level is above the selected minimum and thereby permits normal controller operation.
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Citations
11 Claims
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1. A flow control system having a pressure source means and a line valve means in a flow line to establish a pressurized flow through the line, said pressure source means being operable to establish a selected line pumping pressure level, comprising a controller for selectively operating said valve means to establish a flow cycle, said controller having means operating said valve means in response to an input signal generated independently of said pressure level and including a controllable switch means for actuating the controller, and interlock limit means to sense the pressure in the line with the valve closed and coupled to the switch means to prevent operation thereof and thereby actuation of the line valve means in response to a preselected line pressure less than said selected line pumping pressure level.
- 2. A flow control system having a pressure source means and a line valve means in a flow line to establish a pressurized flow through the line, said pressure source being operable to establish a selected line pumping pressure level, comprising a fluid controller for selectively operating said valve means to establish a flow cycle, said controller having a fluid operated actuator for operating said valve means and said actuator being responsive to a trigger input fluid signal of a first selected level and including a resettable time delay means requiring a trigger input signal of predetermined minimum period, and interlock control means to sense the downstream pressure in the line with the valve closed and coupled to the time delay means to prevent operation thereof and thereby actuation of the line valve means in response to preselected abnormal line pressure conditions less than said selected line pumping pressure level.
- 7. A gravity flow system having a vacuum source means and a line valve means upstream of said source means in a flow line to establish a pressurized flow through the line, said vacuum source means operable to establish a selected vacuum pumping level in said flow line, comprising a fluid responsive controller for selectively operating said valve means to establish a flow cycle, said controller connected to the line upstream of the vacuum source to derive operating fluid from said line and being responsive to a trigger input signal created by the pressure state upstream of said line valve means and including a resettable time delay capacitor means requiring a trigger input signal of a minimum period to operate said valve means, pressure sensing means connected to sense the vacuum level in the line downstream of the valve means, and interlock control means connected to said sensing means and coupled to the time delay capacitor means to prevent timing operation thereof and thereby actuating of the line valve means in response to a line vacuum level less than said selected vacuum pumping level.
Specification