Abrasives and abrasive products are used to remove surface materials such as metal, ceramics, glass, plastics, and paint. Abrasives and abrasive products include discs, belts, blast machines and sandblasters, as well as sheets, rolls, and handpads. Some abrasives and abrasive products are designed for use on bench or back stand grinders, while others are designed for use on portable or handheld grinders or sanders. Bonded abrasives, which include grinding wheels, use abrasive grains held together in a matrix of glass, resin, rubber, or other binders. Coated abrasives consist of an abrasive grain layer adhesively bonded to the surface of a cloth belt, fiber disc, plastic film, paper sheet, or other backing.

Grit size measures the abrasive grains in a matrix or bonded to a surface. Typically, grit sizes are based on ANSI (U.S.), FEPA (European), JIS (Japanese), or Micron graded standards. Typically, bonded abrasives and grinding wheels use ANSI – Bonded and FEPA – F grit size standards. Coated abrasives, grinding belts, and sanding discs use ANSI – CAMI and FEPA – P standards. Coarse grains, or grits, are used to remove large amounts of material, while medium grains are used to remove intermediate amounts. Fine grits are used in finishing and deburring applications, while very fine grits are suitable for deburring.

Abrasives and abrasive products use several different types of abrasive grains. Aluminum oxide, the most common industrial mineral in use today, is used either individually or with other materials to form ceramic grains. Aluminum oxide is also combined with emery and crocus to produce abrasives suitable for finishing applications. Other types of abrasive grains include garnet, tungsten carbine, silicon carbide, and alumina-zirconia. Super-abrasive diamond pastes are useful in ferrous polishing or lapping applications where heat and reactivity are not factors. Cubic boron nitride (CBN), a superabrasive grain with hardness second to diamond and a cubic crystal structure, provides superior grinding performance on carbon and alloy steel.

There are several different backing types for abrasives and abrasive products. Cloth backing is used with abrasives and abrasive products designed for aggressive applications such as abrasive planing. Fiber backing is denser than cloth and contains vulcanized or chemically treated cotton or cellulose fibers; however, fiber may curl under humid conditions. Film backing uses abrasive grains on plastic film, while foam and sponge backing uses abrasive grains bonded onto a foam layer, sponge, felt or other soft, resilient materials. Similarly, metal backing uses abrasive grains bonded onto a metal backing such as aluminum or brass. Other types of backing include paper, screen, non-woven, or aggregate materials.

Abrasives and abrasive products are used in wet and dry grinding, sanding, cleaning, polishing, lapping, and surface preparation in a variety of industries, including metalworking, woodworking, ceramics, and semiconductors. Abrasives and abrasive products are also used to sharpen tools, cut optical components, and finish concrete.

Companies dealing in  Abrasive products

Air valves allow metered flow of fluid in one or both directions. Many of them allow for free flow in one direction and reduced or metered flow in the reverse direction. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices.  Air valves can be configured in-line or at right angles.  In an in-line configuration the input and output ports are on the same axis.  In a right angle configuration the input and output ports are perpendicular.

Flow control choices for air valves include unidirectional (one-way), bi-directional (two-way) or three-way.  In a one-way configuration the valve permits metered (restricted) flow in one direction and free flow in the reverse direction.  In a two-way configuration the valve provides for metered (restricted) flow in both directions.  In a three-way configuration the control provides flow control in three directions.  Flow compensation is an important consideration.  Choices include noncompensated, pressure compensated, and temperature compensated.  In a noncompensated flow control the amount of flow that passes through the orifice and the pressure drop across it are directly related. Flow through the valve varies with the fluid viscosity and pressure across the valve.  A pressure compensated flow control maintains accurate output flow regardless of the input pressure, up to rated limits. The orifice is adjusted to compensate for pressure variations and maintain a set flow rate.  A temperature compensated flow control maintains accurate output flow regardless of the input temperature, up to rated limits. Sharp-edged orifices or expansion rates of dissimilar metals are used to maintain a constant flow rate.  Air valves may have adjustability.  Choices include adjustable flow or fixed flow.  Important performance specifications to consider include metered flow for gas or air, and maximum operating pressure.

Common features for air valves induce integral relief valve, integral bypass, integral check valve, meter in, meter out, tamper-proof, locking nut, and swivel. An integral relief valve is pressure limiting.  An integral bypass controls by diverting or bypassing excess flow.  A check valve offers resistance to flow in only one direction.  If the flow inlet to the actuator is controlled, it is a meter-in system.  If the actuator outlet is controlled, it is a meter-out system.  Tamper-proof controls have a feature such as a removable knob or lock to prevent inadvertent or unauthorized adjustment.  A locking nut on adjustment stem locks the metering setting.  Swivel air valves rotate or swivel for alignment on cylinder in any orientation.  Media choices include air, gas, and steam.  Mounting choices for air valves include cartridge, subplate or manifold, pipe or line mount, port mounted, or stacked or sandwich mount.

Additional specifications to consider when searching for air valves include metered flow input connectors, free flow input connectors, adjustment, and operating conditions.

Companies dealing in Air valves