July 24, 2007

BUBBLE TIGHT: Ability of the valve to seal against gas pressure and not exhibit a detectable bubble of gas leakage in a one minute period during a bubble test.

BUBBLE TIGHT: Ability of the valve to seal against gas pressure and not exhibit a detectable bubble of gas leakage in a one minute period during a bubble test.

CV FACTOR: A value that indicates relative flow capacity of a valve. Cv, is defined as the flow of water at room temperature, in gallons per minute, when the Delta P across the valve equals one PSI.

COIL VOLTAGE: Voltage at which the coil must be energized if the valve or pump is to perform the required function.

CONTINUOUS DUTY: A rating given to a coil capable of working continuously under normal operating conditions without overheating or catastrophic failure.

DEENERGIZED: The state of a valve or pump when no electrical current is being applied to the coil. This is also defined as the normal condition, i.e. normally closed, normally open.

DISPENSING: To create a specific volume of liquid by pulsing a pump one or more times, until the total volume of liquid required has been pumped.

GAGE PRESSURE: Absolute pressure minus atmospheric pressure as measured by a pressure gage, so that gage pressures above atmospheric are positive and gage pressures below atmospheric are negative. The gage pressure of the atmosphere is zero Ib/in gage or zero PSIG.

HEAT RISE: The difference in internal temperature of a coil when deenergized and energized. To calculate heat rise, use the formula: Ambient Temperature + Heat Rise in Coil = Total temperature.

HEMATOLOGY: The study of the function and diseases of the blood. Typical blood analyzers use protein or enzyme analysis to detect various disorders or diseases of the blood.

INTERMITTENT DUTY: A rating given to a coil whose heat rise exceeded the coils temperature rating. Use of an intermittent-duty coil in continuous-duty service can lead to overheating of the coil and possible catastrophic failure.

ORIFICE: A restricted opening through which the media must pass when flowing through the valve. The orifice is opened and closed to permit or stop flow. This is accomplished with a poppet, diaphragm, or floating seal.

PORT: The opening in a valve or pump through which the media enters (inlet) and exits (outlet).

RESPONSE TIME: The time, usually in milliseconds, required to open or close a valve. The response time is affected by voltage, pressure, and media. Typical response times for poppet valves is 15 -20 milliseconds; for diaphragm valves, 25 – 35 milliseconds.

SHADING RING: A silver ring staked into a groove in the stop of all AC valves. Its purpose is to minimize the oscillation or hum usually associated with AC valves. Without the shading ring, AC valves would buzz loudly and quickly beat themselves to premature failure.

STOP: Part of the solenoid assembly that the plunger impacts upon during the energize portion of the cycle. Also refereed to as the plug nut.

VISCOSITY: A measure of a fluid’s resistance to shearing forces. Viscosity generally decreases with rising temperature. While the viscosities of some fluids vary only slightly, the viscosities of other fluids can vary considerably with temperature. Typical units of measure are SSU, Centistrokes, Centipoise.

The terms and definitions for this issue’s Word Search come from a glossary of terms compiled by Valcor Scientific (, a designer and manufacturer of fluid control valves and related components.

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