G Thread : G Thread is the European symbol for BSP British Standard Thread. G threads can be BSPP Parallel or PSPT Tapered.
Galling : Galling is the tearing of metal caused by severe metal to metal friction typically caused by a lack of lubrication.
Gas : Gas is typically referred to as an air like substance which is not a solid or liquid that is compressible such as Argon, Carbon Dioxide, Carbon Monoxide, Freon Gas, Helium, Methane Gas, Natural Gas, Neon, Nitrogen, Nitrous Oxide, Noble Gas, Oxygen, Ozone, Water Vapour, Xenon.
Gasket : A gasket is a seal or packing material placed between to joints to seal and prevent leakage of media passing through. Gaskets are sometimes referred to as diaphragms, O rings or other sealing materials.
Gate : A gate is typically the closing/opening element of a gate valve or non return valve.
Gate Valve : A gate valve controls the flow of media along a pipe by means of a gate which either lifts away allowing flow or drops down preventing flow along a straight line path through the valve. The ports ends are typically in line, the gate is lifted by a rotating threaded stem with is perpendicular to the valve body, usually with a hand wheel or T bar handle for actuation.
General Purpose : A general purpose valve is a valve used for general purpose or non aggressive or corrosive media in the low pressure range, such as air, water, light oils and vacuum. Typically general purpose valves will be Brass bodied, with NBR seals suited to pressures up to 10 bar (150 psi)
Globe Valve : An ON/OFf or open close flow control valve whose closing element is a disc or conical plug which either rests against a horizontal sealing face to allow flow or is raised from a horizontal sealing face to allow flow my means of a perpendicular threaded stem.
GO - Gear Operated : Valve actuation via a gear set or gearbox that can multiply the torque or turning force applied according to the gear ratio through to the valve stem.
Graphite : Graphite is a flexible carbon material used for the manufacture of gaskets, seals and valve packing. Graphite gaskets may be flat sheet and may have metal inserts for added strength or Graphite can be used to impregnate PTFE to improve lubrication for steam solenoid valves.
Gravity Fed : A gravity fed solenoid valve means that the fluid is held in a tank or simply supplied from above without any pump pressure assistance. Typically these pressure from gravity fed systems are very low and require a zero rated solenoid valve. The higher the water or fluid column the higher the hydrostatic pressure, for every 10 meters height will increase the water pressure by 1 bar.
Grease Fitting : An adaptor or threaded fitting through which thick lubricant can be injected into and between moving parts.
Hand Wheel : A valve that is actuated by means of a hand operated wheel that is connected to a valve stem. The rotation of the wheel will in turn move or lift internal components within the valve body to allow or prevent the flow of media passing through.
Hard Facing : A process in which an alloy is welded or deposited onto a valve surface to increase wear resistance or corrosion.
Head : A head refers the the height of an open ended column of water or tank, which exerts pressure in direct relation to its height. See gravity fed systems.
Header : A header is typically a tank filled with fluid at a height above a measured point that exerts a pressure due to gravitational force. See gravity fed systems.
Heat Analysis ; Chemical analysis at the point prior to pouring at the foundry that measures the chemical composition of the liquid metal to be poured. will not include physical properties as metal is in liquid state.
Heat Treatment : The process of heating metal typically steel to a high temperature to change the internal structure of the compound to enhance strength or rigidity. Normally followed by a quick and controlled cooling process to set the material properties.
Horizontal Pattern : A horizontal pattern solenoid or process valve in which the connecting ends are in line with each other for installation into a straight horizontal pipe.
Hot Tapping : A process in which a pipe under pressure is cut into to provide a side outlet. Specialist equipment is used to prevent the escape of media under pressure whilst allowing for a hole to be drilled into the pipe and later secured by means of a shut off valve.
HNBR Seals : HNBR (Hydrogenated Nitrile Butadine Rubber) also known as HSN or Highly Saturated Nitrile Rubber has a high saturation of Butadiene carbon polymer giving higher thermal stability up to 150 degrees centigrade and improved chemical, dynamic loading and abrasion resistance over standard NBR. This is a rare seal to be found in a solenoid valve and only specialist solenoid valve suppliers would be able to offer this option.
HNBR has good resistance to motor oils, sour gas, amine oil mixtures, oxidised fuels, lubricating oils, mineral based hydraulic oil, animal and vegetable oil, diesel fuel, ozone, dilute acids and bases, new bio-oils.
HNBR has poor resistance to concentrated alkali's, esters, alkyl phosphate, ethers, halogenated solvents, ketone's, halogenated hydrocarbons, solvents and flames.
Huey Test : A stainless steel corrosion test for predicting inter-granular corrosion.
Hung Diaphragm : A hung diaphragm valve means that the sealing flexible elastomer diaphragm is attached to or hung from and directly controlled by an actuator or solenoid. As the diaphragm is hung or attached any movement from the actuator or control solenoid will direct move the diaphragm an will not rely on pressure differences. Hung diaphragm also known as kick pilot, forced pilot and assisted lift.
HWO - Hand Wheel Operated : A valve that is actuated by means of a hand operated wheel that is connected to a valve stem. The rotation of the wheel will in turn move or lift internal components within the valve body to allow or prevent the flow of media passing through.
Hydrant : A hydrant is an isolation valve mounted to one side of a pipeline to allow for the release of liquid media into a vessel or container for inspection or analysis.
Hydraulic : The use of liquid media such as oil or water under pressure to control a valve or cylinder. Hydraulic compressed fluid is used to transport energy along a pipe to provide mechanical force where needed.
Hydraulic Control Valve : A valve in which the closing disc, plug or diaphragm is moved or assisted by hydraulic force or differential pressure. See differential pressure.
Hydrostatic Test : A testing process in which a valve is completely filled with water (no air bubbles) and then pressure tested without actuation to provide a proof pressure test for the valve shell or pressure chamber.