A process control arrangement that separates the in-plant measuring points (for example, pressure, temperature, and flow rate) and control points (for example, a valve actuator) from the recorder or indicator at the central control panel.



Related Terms

MULTI-PORT GOVERNOR VALVE

In large turbines, a valve controls steam flow to groups of nozzles. The number of open valves controls the number of nozzles in use according to the load. A bar-lift or cam arrangement operated by the governor opens and closes these valves in sequence. Such a device is a multi-port valve. Using nozzles at full steam pressure is more efficient than throttling the steam.

AUTOMATIC-CONTROL SERVO VALVE

A mechanically or electrically actuated servo valve controlling the direction and volume of fluid flow in a hydraulic automatic control system.

DIRECTIONAL CONTROL SERVO VALVE

A directional control valve which modulates flow or pressure as a function of its input signal.

FLOW CONTROL VALVE

A valve which purpose is to control flow rate in hydraulic system. Used to regulate how slow or how fast actuators operate f.e. hydraulic cylinder.

PHOTOELECTRIC LIQUID-LEVEL INDICATOR

A level indicator in which rising liquid interrupts the light beam of a photoelectric control system; used in a tank or process vessel.

ZONE VALVE

A valve that regulates the flow of hot water or steam in a control zone or heating unit of a building.

THREE-WAY VALVE

Multi-orifice (opening) flow control valve with three fluid flow openings.

OVERRIDING PROCESS CONTROL

Process control in which any one of several controllers associated with one control valve can be made to override another in accordance with a priority requirement of the process.

FOOT VALVE

A one-way valve placed at the entrance of a suction line that is opened by the flow of water. The purpose of the valve is to prevent reverse flow.

SUCTION SIDE

Low-pressure side of the system extending from the refrigerant control through the evaporator to the inlet valve of the compressor.

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