Several Problems Not Neglected in Vacuum System
Several Problems Not Neglected in Vacuum System：
1.When connecting vacuum components such as valves, traps, dust collectors and vacuum pumps to each other, please try to make the pump pipe short and the pipe flow conduction large. The diameter of the pipe is usually not less than the diameter of the pump port. This is an important principle of system design. But at the same time, it is necessary to consider the convenience of installation and maintenance. Sometimes in order to prevent vibration and reduce noise, a mechanical pump can be installed in a pump chamber close to the vacuum chamber.
2.Mechanical pumps (including Roots pumps) can vibrate. In order to prevent the vibration from spreading to the entire system, hoses are usually used to reduce the vibration. There are two types of hoses: metal hoses and non-metal hoses. No matter which type of hose is used, it must be ensured that it will not be crushed under atmospheric pressure.
3.After the vacuum system is completed, it should be easy to measure and detect leaks. Actual production tells us that in the working process of the vacuum system, air leakage often easily affects production. In order to find leaks quickly, it is necessary to perform segmented leak detection. Therefore, for each space enclosed by the valve, at least one measurement point must be provided to facilitate measurement and leak detection.
4.The valves and pipes configured in the vacuum system should make the pumping time of the system short, easy to use, safe and reliable. Generally, in a system with a steam flow pump as the main pump (diffusion pump or booster pump); and a mechanical pump as a backup pump, in addition to the backup pipeline (the pipeline of the steam flow pump in series with the mechanical pump), There should be a pre-vacuum tube (from the vacuum chamber to the mechanical pump). Secondly, there is a high vacuum valve (also called the main valve) between the vacuum chamber and the main pump, and a front valve (also called a low vacuum valve) on the front pipeline. Pre-vacuum pipeline valve (called low vacuum valve) on the pre-vacuum pipeline. The high vacuum valve on the main pump usually cannot be in a vacuum state under the valve cover, and the valve cover is open at atmospheric pressure. This must be secured by an electrical interlock. Precedents and pre-vacuum pipeline valves should take into account that the valve itself can be opened at atmospheric pressure. For the vacuum system with steam flow pump as the main pump, the main valve should cover the main pump, the front valve should also cover the main pump, and the valve cover of the pre-vacuum pipe should cover the vacuum chamber. A bleed valve shall be provided on the inlet pipe of the mechanical pump. When the mechanical pump stops working, the valve can be opened immediately to allow the inlet of the mechanical pump to enter the atmosphere to prevent the mechanical pump oil from flowing back into the pipeline. Therefore, the valve must be electrically interlocked with the mechanical pump. The vacuum chamber shall also be equipped with a vent valve for loading and unloading. The position of the valve should take into account the large pulse of gas during deflation to prevent the weak components in the vacuum chamber from being damaged by excessive pulse. The size of the air release valve is related to the volume of the vacuum chamber, and the air release time should not be too long to avoid affecting the work.