First of all, when vacuum pipe fittings such as valves, traps, vacuum cleaners and vacuum pumps of the vacuum pipe fittings are connected to each other, the suction pipe should be as short as possible and the pipe flow should be large. The pipe diameter is generally not less than the diameter of the pump port. This is important for system design. in principle. However, the ease of installation and inspection should be considered. Sometimes in order to prevent vibration and reduce noise, the mechanical pump can be installed in the pump chamber close to the vacuum chamber.
Secondly, mechanical pumps (including Roots pumps) have vibration. In order to prevent vibration from affecting the entire system, hoses are usually used to dampen vibration. There are two types of hoses: metal and non-metal. No matter which type of hose is used, it must be ensured that it will not collapse under atmospheric pressure.
Then, after the vacuum system is completed, measurement and inspection should be convenient. Production actually tells us that the vacuum system is easy to leak during the working process, which affects production. In order to find loopholes quickly, loopholes should be checked in stages, so at least one measuring point is needed to measure loopholes in the interval where each valve is closed.
In addition, the valves and pipelines of the vacuum system should make the system short inhalation time, easy to use, stable and reliable. Generally, a steam flow pump is used as the main pump (diffusion pump or oil booster pump) and a mechanical pump as the backing pump. In addition to the backing piping (piping for the steam flow pump in series with the mechanical pump), pre-vacuum piping (vacuum The chamber is directly connected to the piping of the mechanical pump). Secondly, a high vacuum valve (also called a main valve) is set between the vacuum chamber and the main pump, a foreline valve (also called a low vacuum valve) is set on the foreline pipeline, and a prevacuum pipeline valve is set on the prevacuum pipeline. (Called low vacuum valve). The high-vacuum valve on the main pump usually cannot be in a vacuum state under the valve cover, and the valve cover is at atmospheric pressure and the valve is opened under the state. This requires electrical interlocking to ensure stability. The front-stage piping valve and the pre-vacuum piping valve should consider the valve itself to open the valve under atmospheric pressure. In the vacuum system with steam flow pump as the main pump, the main valve should cover the main pump, the front-stage piping valve should also cover the main pump, and the pre-vacuum piping valve cover should be directed to the vacuum chamber. On the inlet pipe of the mechanical pump, the air release valve. When the mechanical pump stops working, the valve can be opened immediately to let the inlet of the mechanical pump enter the atmosphere to prevent the mechanical pump oil from returning to the pipeline. Therefore, the valve should be electrically interlocked with the mechanical pump. An air release valve is also set in the vacuum chamber, which is used during feeding and feeding. The position of the valve installation should consider the large gas impact force when venting, so as to prevent the impact force from damaging the weak parts in the vacuum chamber. The size of the exhaust valve is related to the volume of the vacuum chamber. It should be considered that the exhaust time should not be too long, which will affect the work.