Text № 9 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

Text №10 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 fins¹² or 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