Functional Directional Control Valve
Many functional directional pneumatic control valves are classified based on the number of entry and exit ports6 they possess, the number of flow paths they create, and the mechanism by which ports are opened and closed.
Two-Way Directional Valve
A two-way directional valve passes air in two directions, through two ports which can be open or closed. If the valve ports are closed no air can flow through the valve. If the ports are open, air may move from the first port through the valve and through the second port or in the opposite direction.
Three-Way Directional Valve
A three-way directional valve has three ports, each of which serves a different purpose. The first port is used to connect the valve to an actuator or another device. The second port is connected to an air flow. The third port is used as an exhaust exit.
1. pneumatic valve – пневмоклапан; пневмораспределитель
2. array – ряд; серия
3. pneumatic pressure power tool –пневмо-механический инструмент
4. directional control valve –направляющий гидро- или пневмораспределитель
5. inhibit – задерживать, сдерживать, препятствовать
6. entry and exit ports – входные и выходные отверстия
7. two-way directional valve – двухканальный направляющий клапан
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Ball Valves
Stainless Steel ball valves1 are cost effective straight through2 high conductance valves. Their simple, robust design provides high reliability in low vacuum applications. Ball valves are commonly used on CVD3 equipment downstream from the chamber or vacuum pump to isolate traps or abatement tools. A quarter-turn of the handle quickly switches the valve from open to close. Htc’s4 ball valves offer straight-through, unimpeded5 flow with minimal space requirements, and they would be applied for high pressure, high temperature environment.
Angle Valves
Vacuum angle valve5 is one type of the poppet valves6. When the poppet is moved toward the top of the valve, the internal body cavity is open to the system, and flow is unimpeded (maximum conductance). Once the actuator7 moves the poppet to the bottom of the valve, an elastomer sealing ring8 is compressed onto the sealing surface of the lower body of the valve. This action creates a vacuum tight seal9 and stops the flow. Htc offers a wide variety of valve types in a comprehensive range10of sizes. They are manually and pneumatically, with bellows11 and without bellows. Htc designs all series angle valves suited for vacuum applications with venting processes, high vacuum applications in pumping systems, semiconductor technology, research systems, etc.
1. ball valve– шаровой клапан
2. straight through–прямоточный
3. CVD (chemical vapor deposition) – хим. осаждение из паровой или газовой среды
4. [Hughes Tool Company] "Хьюз тул компани" (название компании)
5. unimpeded – беспрепятственный, свободный
6. angle valve– угловой клапан
7. poppet valves – тарельчатый [дисковый] клапан
8. actuator – силовой привод; рукоятка привода
9. sealing ring – уплотнительное кольцо, кольцевое уплотнение
10. tight seal – герметичное уплотнение
11. comprehensive range – полный ассортимент
12. bellow(s) – сильфон; гофрированная мембрана; гофрированная трубка
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Heat exchanger
A heat exchanger1 is a piece of equipment built for efficient heat transfer2 from one medium3 to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants4, chemical plants, petrochemical plants, petroleum refineries5, natural gas processing, and sewage6 treatment. The classic example of a heat exchanger is found in an internal combustion engine7 in which a circulating fluid known as engine coolant8 flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air.
There are three primary classifications of heat exchangers according to their flow arrangement. In parallel-flow heat exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow9 heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is the most efficient, in that it can transfer the most heat from the heat (transfer) medium due to the fact that the average temperature difference along any unit length is greater. See countercurrent exchange. In a cross-flow10 heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.
For efficiency, heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The exchanger's performance11 can also be affected by the addition of fins12or corrugations13 in one or both directions, which increase surface area and may channel fluid flow or induce turbulence.
1. Heat exchanger - теплообменник
2. Heat transfer - теплопередача
3. Medium (media) - среда
4. Power plant – электростанция, электроустановка
5. Petroleum refinery – НПЗ
6. Sewage – сточные воды
7. Internal combustion engine – двигатель внутреннего сгорания
8. Сoolant– охладитель, хладогент
9. Рarallel-flow heat exchanger –теплообменник с параллельным током
10. Counter-flow heat exchanger – теплообменник с противоток
11. Cross-flow heat exchanger – теплообменник с перекрёстным током
12. Performance – производительность
13. Fin – ребро, пластина
14. Corrugation– рифление
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