Categories Starting with 'H'

A heat exchanger is used for transferring heat from one medium to another. It is also used to induce either a temperature change or a phase change in the working medium. The mediums, between which the heat transfer occurs, can either be gaseous, liquid or a combination of both. There are various types of heat exchangers, such as the shell & tube type as well as the plate type, the choice of which depends on the application and its requirements. Heat exchangers are used in a number of industries for heat transfer purposes and can be found in a variety of applications, ranging from power plants and petroleum refineries to domestic air conditioning and refrigeration systems. A common example is the radiator in a car, where the air is used to cool the liquid in the radiator.

Hypodermic tubing is a specialized type of tubing with small diameters, produced by rolling a strip of metal, welding, and then hard drawing it to the final shape. A seamless look is simultaneously provided to the tubing. This tubing is commonly manufactured from different grades of stainless steel, including type 304 or type 316L stainless steel, which is particularly ideal for biomedical purposes due to its excellent resistance to corrosion. Hypodermic tubing is used in a range of industries, such as medical and aerospace, in nozzles, spacers, and needles.

A hydraulic valve is any valve used in a hydraulic system. Such a system uses fluid pressure to multiply force by virtue of hydrostatic pressure and to transfer large amounts of energy by small flows of highly pressurized fluid. Valves used in this system can include angle, check, safety, ball, shut off, solenoid, control, directional, drain, needle, cartridge, poppet, pressure relief or spool valves.

Hydraulic hoses are fluid-conveying pipes contrived for the conveyance of hydraulic fluid to or among hydraulic constituents, actuators and tools. The hoses are flexible and are frequently subjected to reinforcement. Hydraulic systems tend to operate at high and extremely high pressures; therefore numerous reinforcement techniques and multiple layers are used in the design of the hose. They are of ideal usage for agricultural, industrial and plant machinery including cranes, coal cutters, dumpers, dozers, hydraulic roof supporters, loaders, shovels, excavators, lathers, tractors, harvesters, steel and cement industry and equipment used in surface and underground mining.

Hose pumps are the high pressure handling variants of peristaltic pumps. In this type of pump, the conventional tubes are replaced with reinforced hosing that offers better fatigue resistance and pressure handling capabilities. Hose pumps can typically handle pressures of up to 230 psi (16 bar), a significant increase over conventional tube pumps. In addition, their high pressure handling capability also allows them to transport aggressive fluids with viscosity in excess of 10000 cps. Due to their reinforcement the walls of hoses are thick and require a larger force for constricting action. The thicker hoses make this type of pump consume more power than conventional tube pumps. The casings in hose pumps are typically lubricated to assist in better constriction of the hoses. Hose pumps are ideal for pumping aggressive and sterile fluids in the medical industry, and for clearing blockages plus emptying lines.

Hot melt adhesives are solvent-free low viscosity fluids above 180°F that quickly set into solids at temperatures below 180°F. They are used in box and carton heat sealing, bookbinding, assembly and other manufacturing. Hot melts include a copolymer mixed with a hardening resin, wax or plasticizer. Ethylene vinyl acetate copolymers, compatible with paraffin, was the original hot melt.

A pump that discharges pressure greater than 800 psi is known as a high pressure pump. Pumps classified as moderate high pressure discharge pressure between 800 and 3000 psi, and those classified as very high pressure pumps discharge pressures ranging from 3000 to 5000 psi. Another type of pump based on the same classification is the ultra high pressure pump, which discharges pressure well in excess of 5000 psi, in many cases ranging from 10,000 psi to 40,000 psi. Some common high-pressure pumps are triplex plunger pumps and quintuplex plunger pumps. Another device that can generate high pressure is a hydraulic intensifier or amplifier, which uses hydraulically actuated piston to pressurize the working fluid.

Hydroforming is an industrial manufacturing process that uses hydraulic pressure to shape and form metal into the desired shape. It is a die forming process and uses pressurized hydraulic fluids to press a room temperature metal blank into a negative die, so that it takes the shape of the die. This process is commonly used to shape malleable metals such as aluminum as well as brass, and is extensively used for various applications in the automotive industry.

High temperature gaskets are specialized seal types contrived for heat-sensitive industrial applications. The gaskets are fabricated by combining a tubular casing of woven or braided inorganic filaments such as alumina-boria-silica fibers with a composition that contains an intumescent material, preferably unexpanded vermiculite, in order to exhibit superior thermal resistance and sealability in large proportions. Silicone rubber is the common material used for the fabrication of these gaskets. Gaskets of this type are used to prevent leakage of reactor gases in flanged connections and ceramic metal joints, and in exhaust applications.

A Highly Accelerated Stress Test (HAST) Chamber reduces the time for humidity testing of semiconductors from weeks to days by using a temperature over 100°C, high RH of 85%, and high atmospheric pressure conditions of 4 atm. HAST, also called an Autoclave or Pressure Cooker Test, evaluates the non-hermetic packaging of solid state equipment by accelerating the penetration of moisture through the external protective material or at the seals around the chip leads.

A Highly Accelerated Stress Test (HAST) Chamber reduces the time for humidity testing of semiconductors from weeks to days by using a temperature over 100°C, high RH of 85%, and high atmospheric pressure conditions of 4 atm. HAST, also called an Autoclave or Pressure Cooker Test, evaluates the non-hermetic packaging of solid state equipment by accelerating the penetration of moisture through the external protective material or at the seals around the chip leads.

High pressure check valves are valves that allow flow in only one direction and are manufactured to withstand high pressure applications (>500 psi).