In accordance with the resent invention, there is provided a fugitive emission detection system for use in conjunction with a valve having a packing deign which includes a primary packing and a secondary packing. The valve further includes a leak port which is disposed within the valve bonnet between the primary and secondary packings. The detection system is operative to maintain the leak port in a normally open state. As a result, any fluid leakage past the primary packing is normally sent to the detection system, as opposed to being applied to and thus pressurizing the secondary packing. In the event of that a prescribed level of fluid leakage beyond the primary packing is detected, the leak port will be closed. The closure of the leak port facilitates the pressurization of the secondary packing.

A distributed control system for a vacuum sewer system comprising a suction pipe which is communicated with a vacuum source via a transport conduit (520) by opening a vacuum valve (530) using a solenoid valve is disclosed. The transport conduit is connected between the vacuum valve and a collection tank, with the collection tank having a vacuum source relative to atmospheric pressure applied thereto. The suction pipe is connected between the vacuum valve and a sewage sump, with the sewage sump have a source of sewage maintained at atmospheric pressure. Sewage (551) in the sump is sucked through the suction pipe and sent to the collection tank via the transport conduit by opening the vacuum valve. A transport conduit section is laid out in a sawtooth fashion, having in series transport conduit portions comprising a low-point conduit portion (522), a riser conduit portion (521), and a down-slope conduit portion (523). A valve pit apparatus (500) for control and monitoring the valve pit operations is provided with a battery powered electronic computer, a plurality of sensors, and a solenoid valve. A transport conduit apparatus for monitoring the transport conduit conditions is provided with a riser conduit sensor (550) capable of detecting sewage conditions within the riser and communicating the conditions to a computer (551) for processing. When the vacuum valve (530) is intermittently opened by control of the valve pit apparatus (500), sewage (551) in the sump is intermittently injected under the influence of atmospheric pressure into the transport conduit (520) for transportation to the collection tank, which passes through the transport conduit riser (521) and detected by the transport conduit apparatus for processing. The results of the valve pit apparatus and the transport conduit apparatus processing are stored in computer memory as operating parameters and then wirelessly communicated to devices external of the valve pit apparatus and transport conduit apparatus. The distributed control system provides an apparatus and method for control and monitoring of the vacuum sewer system, which is complex in sensor placement operating parameters processing but simple in structure, easy to maintain and capable of stable operation.

A flow control device equipped with flow monitor includes a build-down type flow monitor unit provided on an upstream side, a flow control unit provided on a downstream side of the build-down type flow monitor unit, a signal transmission circuit connecting the build-down type flow monitor unit and the flow control unit and transmitting a monitored flow rate of the build-down type flow monitor unit to the flow control unit, and a set flow rate value adjustment mechanism being provided in the flow control unit and adjusting a set flow rate of the flow control unit based on the monitored flow rate from the build-down type flow monitor unit.

Mass flow controllers and methods for controlling mass flow rates are disclosed. A mass flow controller includes a pressure value measurement means that measures one or two or more pressure values derived from pressure P1 of fluid on an upstream side of a pressure difference generate means and pressure P2 of the fluid on a downstream side of the pressure difference generate means, an acceleration means accelerates time variation of the obtained pressure values, a flow meter calculates a flow rate of the fluid based on a pressure value obtained according to the accelerated time variation (accelerated pressure value), and a flow control valve controls the flow rate of the fluid based on the calculated flow rate.

In order to keep a stable flow rate at a set flow rate value when a pressure fluctuation occurs in an upstream side of a valve, without providing an additional sensor for detecting a pressure fluctuation, a flow rate control apparatus is provided with: the valve; a flow rate sensor; a valve control part configured to control the valve so that a deviation between a set flow rate value and a measurement flow rate value is reduced, on the basis of the deviation and a set control coefficient; and a control coefficient setting part configured to set the control coefficient so that when a pressure rise occurs in the upstream side of the valve, a decreased amount in flow due to a decreased opening of the valve and an increased amount in flow due to an increased amount of a differential pressure before and after the valve, are balanced.

A steam valve control device of this embodiment controls a steam valve. The steam valve has: an upper cover in whose through hole a bush is installed; and a valve rod which is installed so as to penetrate through the through hole of the upper cover via the bush. The valve rod has a contact surface which is formed so as to come into mechanical contact with the bush when the steam valve is opened to a maximum opening degree. The steam valve control device has a control part. When a governor free operation is performed, the control part controls the steam valve by setting a limited opening degree limited to be smaller than the maximum opening degree as an upper limit. When a load limiter operation is performed, the control part controls the steam valve by setting the maximum opening degree as the upper limit.

A drive circuit is provided for controlling a solenoid valve having a solenoid coil. The drive circuit includes a first semiconductor device, a flyback circuit, and a processor. The first semiconductor is coupled in series with the coil and is controlled by a gate signal to energize the coil. The flyback circuit is in parallel with the coil and includes a series-coupled second semiconductor device and a diode. The second semiconductor is controlled by a flyback control signal to enable the flyback circuit when the first semiconductor is controlled by the gate signal to hold the valve open. The diode has a low forward voltage to slow decay of a current conducted through the coil. The processor generates the gate signal to control the first semiconductor and to reduce a duty cycle of the gate signal when the flyback circuit is enabled to reduce power consumption by the coil.

A flow control device is disclosed. The flow control device includes a solenoid, the solenoid including an armature. Also, a piston connected to the armature. The piston includes a primary orifice. The piston having an open position and a closed position. A piston spring connected to the piston is also includes and at least one secondary orifice. The movement of the piston to the open position at least partially opens the at least one secondary orifice and the movement of the piston to the closed position at least partially closes the at least one secondary orifice. The movement of the armature actuates the piston movement and controls fluid flow from the primary orifice through the at least one secondary orifice.

The invention provides methods for assessing one or more predetermined characteristics or properties of a microfluidic droplet within a microfluidic channel, and regulating one or more fluid flow rates within that channel to selectively alter the predetermined microdroplet characteristic or property using a feedback control.

An automatic excess water flow saving system reduces the water loss by water outlets in houses and other water consuming installations. The system controls the water flow through an outlet by toggling the water flow rate. An actuator activates a timer which opens and closes a valve intermittently and continuously while a water outlet is open.