Glossary
Analog Position Sensor: A type of position sensor whose voltage output varies over a range of values.
Body: The component of a pinch valve that secures the tubing.
Closed State: The state a pinch valve is in when the tubing is pinched.
Continuous Duty: Energizing a solenoid valve at a constant level of power for its entire on-time.
Dashpot: A mechanical device used to decrease plunger velocity for controlling noise.
Digital Position Sensor: A type of position sensor whose voltage output has only two states.
Drop-Out Voltage: Refers to the power level at which the internal forces in the solenoid valve (spring and friction) overcome the magnetic field and can no longer maintain a latched condition. Drop-out voltage is one of the
measurements used to determine solenoid limits.
Durometer: A standard for quantifying the hardness of rubber, plastic, and other non-metallic materials. Typical hardness of flexible tubing ranges from 50 to 70 Durometer on the "A" scale.
Duty Cycle: The relationship between the energized and non-energized time of an electric pinch valve usually expressed as a percentage (%). Duty cycle is determined by (ON time) / (ON time + OFF time). For example
if a pinch valve is energized for 1 second out of 4 seconds, the duty cycle is 1/(1+3) = 1/4 = 25%.
Feedback: The output from a position sensor indicating the position, or state, of the valve.
Hall Effect Sensor (Hall Sensor): A type of position sensor that senses magnetic field strength and produces a voltage that changes with this strength. Hall sensors can have digital or analog outputs.
Heat Rise: The rise in temperature above ambient that results from operating an electric pinch valve at predetermined conditions.
Hold-In Voltage: Refers to the power required to maintain a latched condition within a solenoid, keeping the plunger (or moving core) magnetically latched to the fixed pole. Power required for hold-in is approximately 10% of the
pull-in power (4-7W). Operating solenoids at a low power hold level saves energy and heat.
Manual Override: A button that allows the valve's state to be changed manually.
Media: The substance that flows through the tubing, either a gas, liquid, powder or slurry.
Media Pressure: The pressure of the media inside the tubing.
Micro Switch: A type of digital position sensor that is mechanically linked to a valve.
Normally-Closed (N/C) valve: A pinch valve that in which the tubing is pinched in the de-energized state.
Normally-Open (N/O) valve: A pinch valve in which the tubing is not pinched in the de-energized state.
Open State: The state a pinch valve is in when the tubing is not pinched.
Pinch Force: The force exerted by the pinch valve on the tubing in the CLOSED state, usually enough to set a level high enough to occlude flow.
Pinch Gap: The distance between opposed pinching surfaces when a pinch valve is closed.
Pinch valve: A device used to pinch and unpinch flexible tubing for the purpose of controlling flow.
Pinching Surfaces: The surfaces of components in a pinch valve that pinch the tubing, usually the pinch ridge and plunger.
Plunger: The component of a pinch valve that translates during a change of state and pinches the tubing.
Pneumatic Pinch Valves: A type of pinch valve that uses pneumatic pressure to actuate the plunger.
Position Sensing: Using electronic sensors to monitor the valve's position and provide electronic feedback indicating the valve's position to a human user or computer.
Pneumatic 3-Way Control Valve: Typically a 3-way solenoid valve used to send actuating air pressure to a pneumatic pinch valve.
Pull-In Voltage: Refers to the power required to overcome internal forces in the solenoid valve (spring and friction) and to reach a latched condition. Latching is achieved when the plunger (or moving core) has moved through its
stroke as a result of the solenoid field and becomes magnetically latched to the pole (or fixed core). The time it takes to move the plunger is called the pulse duration, which is a high power (40-70 W) spike for a short period of time (200-500 ms).
Pulse and Hold: A technique for increasing performance of solenoid valves by minimizing power consumption and heat generation. The valve is opened with a pulse of DC power and held open at reduced power
Snap-In Tube Loading: A feature of Acro pinch valves that allows tubing to be installed in the valve without requiring a free end; the middle of the tubing "snaps in" the body.
Solenoid Controller (Pulse and Hold): A programmable device designed to be part of the control circuit in a fluid control system. This device is capable of enhancing solenoid performance; including long on times, high cycle rates,
power and heat reduction.
Solenoid Pinch Valves: A type of pinch valve that employs electrical energy and a solenoid to actuate the plunger.
Splash Seals: Internal plunger seal and external mounting seal guard against spills and debris, prevent contaminants from entering valve, and allow for cleaning without disassembly.
Stroke: The distance the plunger translates during a change in state.
Total Opening: The distance between opposed pinching surfaces when a pinch valve is open. The total of pinch gap and stroke.
Tube Detection: A sensor technique for determining the presence of tubing within a pinch valve. By using an analog hall sensor capable of multi-position output, various valve states are established. Typical states are; Tube Out-Valve
Closed, Tube In-Valve Closed and Tube In-Valve Open.
Tube Slot: A slot in the side of the body for tubing to pass through.
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