Vacuum system structure
A complete vacuum system consists of a wide range of vacuum application equipment, vacuum system column mainly describes the design of the main parameters in the vacuum system, the calculation of the pumping time, the influence of the exhaust on the vacuum system, the selection of vacuum pumping unit, the design of ultra-high vacuum system knowledge.
Vacuum system is actually a similar name for vacuum unit. Vacuum unit is a closed-loop vacuum equipment composed of several vacuum pumps. It does not necessarily have some equipment such as radiators, condensers and so on. Generally, the vacuum system is sure to be complete. There are many kinds of vacuum application equipment, but no matter what kind of vacuum application equipment has a set of exhaust system to exclude the gas in the vacuum vessel, in order to obtain the necessary vacuum conditions in the vacuum vessel.
For example:a container for vacuum treatment is connected to a vacuum pump by pipes and valves. When the vacuum pump evacuates the container, there is a vacuum measuring device on the container. This constitutes the simplest vacuum pumping system. So how many pumps does a vacuum system consist of compared to a unit? This is not certain. Let’s first understand the term “pump” that may exist.
KT Series Oil Diffusion Pump
Technical Parameters:
| Item | KT-100 | KT-160 | KT-200 | KT-250 | KT-300 | KT-320 | KT-400 | KT-500 | |||||||
| Ultimate pressure (Pa) | 5×10-5 | ||||||||||||||
| Pumping Capacity (L/S) | 550 | 1800 | 2800 | 3500 | 4600 | 5000 | 8500 | 12000 | |||||||
| Critical fore-pump pressure (Pa) | 40 | ||||||||||||||
| Backflow rate mg/(cm2·min) | ≤3×10-2 | ||||||||||||||
| Heating time ( min) | ≤30 | ≤35 | ≤40 | ≤45 | |||||||||||
| Heating Power (kw) | 0.8-1 | 1.4-1.6 | 1.6-1.8 | 2.2-2.4 | 2.4-3 | 4~5 | 4~5 | 6~8 | |||||||
| Electric Voltage (AC)V | 220 | 380 | |||||||||||||
| Pump Oil Model | KS-3 | ||||||||||||||
| Pump Oil Volume ( L) | 0.15 | 0.45 | 0.55 | 1-1.4 | 1-1.6 | 1.4-1.8 | 3~4 | 4 | |||||||
| Cooling water consumption (L/H) | 180 | 250 | 300 | 350 | 400 | 420 | 500 | 600 | |||||||
| Inlet dimension (mm) | 100 | 160 | 200 | 250 | 300 | 320 | 400 | 500 | |||||||
| Outlet dimension (mm) | 32 | 50 | 65 | 65 | 80 | 80 | 100 | 100 | |||||||
| Recommended forepump speed (L/s) | 4 | 8 | 15 | 15 | 30 | 30 | 70 | 150 | |||||||
| Dimension (mm) |
L(Length) | 320 | 420 | 530 | 473 | 695 | 725 | 885 | 1010 | ||||||
| B(Width) | 260 | 315 | 390 | 450 | 505 | 525 | 665 | 815 | |||||||
| H(Height) | 365 | 505 | 575 | 650 | 726 | 830 | 925 | 1165 | |||||||
| Net weight (kg) | 14 | 31 | 39 | 48 | 89 | 100 | 175 | 185 | |||||||
Main pump: In a vacuum system, the vacuum pump used to obtain the required vacuum to meet the specific process requirements, such as the oil diffusion pump in the vacuum coating machine is the main pump.
Front stage pump: a vacuum pump used to maintain a pre vacuum pressure below a critical pre pressure level of a vacuum pump. For example, the rotary pump or slide valve pump equipped with roots pump is the front stage pump.
Coarse pumps: Vacuum pumps that start at atmospheric pressure and pump the system pressure to another vacuum pump to start working. For example, the slide valve pump in the vacuum coating machine is the crude oil pump.
Maintenance pump: in the vacuum system, the volume of gas is very small, and can not effectively use the former pump. To this end, a smaller auxiliary pump is used to maintain the main pump. This pump is called a maintenance pump. For example, a small rotary vane pump at the outlet of the diffusion pump is to maintain the pump.
In fact, a simple vacuum system can only obtain a rough vacuum, and in order to obtain high vacuum, usually in a vacuum system in series with a high vacuum pump, such as Roots pump and screw pump are to obtain high vacuum pump. When a high vacuum pump is connected in series, valves are usually added at the inlet and outlet of the high vacuum pump to keep the vacuum alone.
It is considered that if the series high vacuum pump is an oil diffusion pump, in order to prevent a large amount of oil vapor from flowing back into the pumped vessel, a trap – water-cooled baffle is usually added at the inlet of the oil diffusion pump. According to the requirement, dust collector, vacuum relay gauge head, vacuum soft connection pipe, vacuum pump inlet bleed valve, radiator and so on can be added in the pipeline, thus forming a more perfect high vacuum system.
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