Water Ring Vacuum System

Water ring vacuum pump unit when use in addition to the matters should pay attention to the use of it, you also need to pay attention to its using steps, in order to better use of the product, we’ll need it to have a general understanding of the use of requirements, in addition to the understanding of products more, we can use it better, so today we will require to use it to do a simple introduction to you.

Nine advantages of water ring vacuum pump unit:

1. The working pressure of the water ring vacuum pump unit should meet the requirements of the limit vacuum and working pressure of the vacuum equipment. For example, vacuum coating requires a vacuum degree of 1 * 10-5mmHg, and the vacuum degree selected should be at least 5 * 10-6mmHg. Usually, the vacuum degree of the pump is higher than that of the vacuum equipment. The vacuum degree is half to one order of magnitude.

2. choose the right point of work. Each pump has a certain range of working pressure, such as: diffusion pump is 10-3-10-7 mmHg, in such a wide range of pressure, pump speed varies with pressure, its stable working pressure range is 5 *10-4-5 *10-6 mmHg. Therefore, the working point of the pump should be selected within this range, and can not allow it to work under 10-8 mmHg for a long time. For example, Ti sublimation pump can work under 10-2mmHg, but its working pressure should be less than 1 * 10-5mmHg.

3. The water ring vacuum pump unit should be able to drain all the gas produced in the process of vacuum equipment under its working pressure.

4. correct combination. Because it has selective pumping, so sometimes choose a pump can not meet the pumping requirements, the need for a combination of several pumps to complement each other to meet the pumping requirements. If the titanium sublimation pump has a high pumping speed for hydrogen, but can not pump helium, and the three-pole sputtering ion pump (or the two-pole asymmetric cathode sputtering ion pump) has a certain pumping speed for argon, the combination of the two will make the vacuum device get better vacuum. In addition, some can not work at atmospheric pressure, the need for pre-vacuum; some outlet pressure is lower than atmospheric pressure, the need for a front-stage pump, it is necessary to pump together.

WHAT ARE ROTARY PISTON VACUUM PUMPS

Rotary piston vacuum pump, full-name mechanical vacuum pump with oil seal of sliding valve, referred to as piston vacuum pump, is a variable volume gas transfer pump, the scope of application and conditions of use are basically the same as rotary vane pump.

Because of its structural characteristics, the capacity of the piston vacuum pump is much larger than that of the rotary vane vacuum pump, so it is more widely used in large vacuum equipment. The basic types of slide valve vacuum pump are also divided into two types: single stage and two-stage. The limit pressure of small pump in single-stage pump is generally not more than 0.6 Pa, the maximum pressure of large pump is not more than 1.3 PA (all closed town); the limit pressure of double-stage pump is not more than 0.06 Pa (closed town). The sliding valve vacuum pump with pumping speed over 150L/s adopts single stage.

Because the rotary mass of the piston vacuum pump has greater eccentricity, there is no good mass balance, and it will produce greater vibration when running. At the same time, it is difficult to realize the complete balance of inertia force of the sliding valve pump because the locus of rotation center of mass of the sliding valve pump is a complex closed curve. This limits the sliding valve type vacuum pump revolution, generally controlled in 350 ~ 600 R / min, individual can reach more than 1000 R / min.

Screw Pump Of Technology

At present, the development of various vacuum pumps is increasingly affected by vacuum applications. The general vacuum system can not meet the requirements of clean and oil-free corrosion resistance. Therefore, in recent years, the market demand of dry vacuum pumps is very large. Vacuum products have been replaced. A large number of oil-free vacuum systems have been replaced by oil-free vacuum systems. Clean vacuum system instead.

Dry screw vacuum pump has become the preferred vacuum acquisition equipment in the microelectronics, semiconductor, pharmaceutical, precision processing and other industries in Europe, the United States and Japan due to its superior performance. On the basis of screw compressor, Japan developed the multi-head rotor profile of vacuum pump very early and put it into the market. Several German vacuum equipment companies have gradually developed rotor profiles with constant pitch and variable pitch, and have done a lot of research on rotor and body cooling.

The structure of dry screw pump:

The structure of screw vacuum pump is mainly composed of screw rotor, shell, cooling cycle and sealing material. The drive shaft is connected with the active rotor, and the driven rotor is rotated by the synchronous gear. A cooling water channel is opened on the shell to cool the rotor and the exhaust temperature, and the synchronous gear and the bearing oil are lubricated. The bearing and housing are sealed by seals to achieve an oil-free effect. The dry screw vacuum pump is similar to the oil-free screw compressor in sealing and lubrication.

Key technical problems of screw pumps:

The exhaust port of the general vacuum pump is mechanically sealed, and the inlet side is commonly used with double lip seals. In the transmission mode, the current general is the direct-connected motor, with a coupling and rotor connection, very few belt or chain drive. The exhaust temperature of constant pitch screw pump is very high (about 110 degrees) because of no internal compression process. If the cooling effect is not good, the rotor and casing will deform, affecting the sobbing effect. So the cooling casing is an indispensable link, and water cooling is the most common method. Through cooling water on the outer side of the bearing body, the cooling shell can be cooled and the rotor can be cooled. The water cooling of the rotor inside the rotor increases the life of the rotor and achieves a good cooling effect. But the structural design (two stage) requires a certain level of technical and processing support. Water cooling sometimes can not achieve cooling effect, so usually near the exhaust end of the rotor cooling gas (mostly nitrogen).

Now the mainstream screw vacuum pumps abroad use this method. This method has several advantages: firstly, it can cool the rotor casing and reduce the exhaust temperature; secondly, when the gas contains particulate matter, it can prevent the deposition of particulate matter or chemical reaction causing explosion.

Vacuum Pump Curve

The stator curve of the vacuum pump has a direct impact on its pumping rate and other performance parameters. Therefore, it is very important to obtain an excellent stator curve for the vacuum pump planning. Regarding the stator curve of vacuum pump, there are the following requirements:

1. Suitable two distance
Because the blade is designed as one, the rigidity is strengthened, and the elasticity at one end must form the corresponding elasticity at the other end. So, no matter the rotor goes to a beep angle. It is necessary to ensure that the curve is in contact with both ends of the rotary vane. Adhere to a reasonable gap. To prevent the emergence of void phenomenon, resulting in increased berthing.

2. Dlade without impact vibration, excellent noise
Smooth stator curve can not have too much acceleration, too much acceleration will lead to one end of the rotor blade on the stator curve surface of the dish pressure increases, will increase wear and voice. But assuming that the radial velocity at a point on the stator curve is 4) changing, the radial acceleration at that point is assumed. Theoretically, it equals infinity. If a is infinite. The leaves will suddenly break away from this point, which will cause great impact. A loud voice and severe grinding. In order to eliminate this phenomenon, we request the stator curve to be smooth and continuous.

3. Make the rotary force outstanding
The angle between the vector diameter of a stator curve and the normal line of the curve is the pressure angle of the stator curve. With the increase of pressure angle, the force acting on the stator against the rotating blade and the angle between the direction of the rotating blade are increased, the transverse force acting on the rotating blade is increased, the resistance between the rotating blade and the rotor is increased, and the force acting on the blade is deteriorated, which affects the service life and the overall power of the pump.

4.There is a larger pumping rate
Vacuum pump does not increase the pump body standard, as far as possible increase the volume area of the rotary vane pump unit, in order to obtain a higher pumping speed string.

The new stator curve should have the speed and acceleration characteristics of the existing curve as well as the increase of the pumping rate. At present, the stator curve of vacuum pump is dominated by a positive circular curve. The main consideration is that the positive return curve has excellent speed and acceleration characteristics, reducing the voice and impact in the process of vacuum pump operation.

COMPOSITION OF THE DIFFUSION PUMPING SYSTEM

COMPOSITION OF THE DIFFUSION PUMPING SYSTEM :

The diffusion pump system mainly consists of diffusion pump, cold trap, gate valve and mechanical pump. For example, in a vacuum system with low oil return rate, there is no need to configure a liquid nitrogen cold trap, only a water-cooled baffle plate is needed. In applications where the oil return rate is strictly required, a liquid nitrogen cold trap should be installed in the system, and a local water cooling baffle may be used. The liquid nitrogen cold trap is mainly used to capture the water vapor and the light fraction reflux in the pump working fluid. The net pumping rate of air at the entrance of vacuum chamber for a 150 mm diffusion pump set is about 1000L/s, and the pumping rate of water vapor by the liquid nitrogen cold trap is as high as 4000L/s. A well designed and manufactured diffusion pump system can reduce the oil return rate from the working fluid of the pump in the vacuum chamber to a very low level, even smaller than that from other sources of organic matter.

DIFFUSION PUMP SYSTEM:

In a smaller vacuum system, a mechanical pump can be used alternately for the coarse vacuum chamber and as the front-stage pump of the diffusion pump. When roughing, the pressure in the partitioned preceding pipeline will increase. If the roughing time is less than 15 minutes, the pressure increase is usually not obvious. For large vacuum systems, such as diffusion pump pumping systems with a diameter of 400 mm or larger, a Roots pump unit with a mechanical pump as the front pump is often used for rough pumping of the vacuum chamber. In the rough extraction process, a smaller maintenance pump can be used as the front pump of the diffusion pump. When the vacuum chamber is pumped to a high vacuum (after the inlet pressure of the diffusion pump is reached), the Roots pump is switched to the front stage of the diffusion pump to ensure that the pumping system has the maximum exhaust capacity.

2BE Series Liquid Ring Vacuum Pump

2BE Series Liquid Ring Vacuum Pump:

2BE Series Liquid Ring Vacuum Pump and compressor are developed by our company on the basis of many years of scientific research and production experience, combined with the advanced technology of similar products in the world, high efficiency and energy-saving products are usually used to suck gases that are not solids, insoluble in water and non-corrosive, so as to form vacuum and pressure in sealed containers. . By changing the result material, it can also be used for sucking corrosive gas or working fluid with corrosive liquid.

2BE Series Liquid Ring Vacuum Pump structure:
2BE Series Liquid Ring Vacuum Pump adopts single-stage and single-acting structure, which has the advantages of simple structure, convenient maintenance, reliable operation, high efficiency and energy saving, and can adapt to the harsh working conditions such as large drainage, load fluctuation.

The key parts of 2BE Series Liquid Ring Vacuum Pump, such as distributor plate, impeller and pump shaft, are optimized systematically, which simplifies the structure, improves the performance and realizes energy saving. The impeller and pump shaft are fitted with thermal fit interference, which has reliable performance and smooth operation. After the impeller is welded, the whole operation is good heat treatment, the blade has good toughness, so that the blade’s impact resistance and bending resistance can be fundamentally guaranteed. The 2BE water-ring vacuum pump can adapt to the harsh conditions of load shock fluctuation.

2BE Series Liquid Ring Vacuum Pump, with gas-water separator, multi-position without exhaust port, pump cover with exhaust valve overhaul window, impeller and distributor plate clearance through the positioning shaft pressure cover adjustment, easy to install and use, easy to operate, easy to maintain.

Diffusion Pump System

Diffusion pump is currently one of the most widely used and most important tools for obtaining high vacuum, usually referred to as oil diffusion pump. Diffusion pump is a secondary pump. It needs mechanical pump as the front stage pump.

Common faults of the diffusion pump system and their elimination measures:
(1) If the diffuser pump pumping system does not leak and the limit pressure of the system has not reached the expected results, it may be unreasonable system design and low effective pumping speed; or the electrode bleeding of the vacuum gauge and the vacuum gauge itself are limited by photocurrent and can not measure the low pressure.

(2) If the pumping performance of diffusion pump or unit deteriorates gradually after long-term use, that is, the limit vacuum degree and pumping speed decrease, and other normal conditions, the diffusion pump oil is gradually oxidized and the quality deteriorates. At this time, new diffusion pump oil should be replaced. The oil change step is: first unload the diffusion pump, take out the pump core, according to the requirements of the pump core cleaning and drying after the correct assembly and adding new oil.

(3) When the diffusion pump suddenly leaks into the atmosphere due to special reasons, such as bursting of vacuum gauge tube, misopening of the vacuum vessel vent valve or not closing the high vacuum valve, the high vacuum valve should be closed immediately, the diffusion pump should be stopped heating and the oil pan should be forced to cool down. After the failure is eliminated, the pumping test should be performed and the pump oil should be replaced according to the result.

(4) After the diffusion pump is disassembled and assembled into the system, if the system is pumped strictly according to the aforementioned operating procedures, it should be able to reach the original limit pressure of the pump; if the gap between the nozzles is carefully adjusted repeatedly, the vacuum should also be increased. If the vacuum can not be pumped, first check whether the leakage rate of the pump system is over the allowable value; at the same time check whether the heater of the diffusion pump is burned out, whether the supply voltage is normal, whether the cooling of the pump is normal. If all the above aspects are normal, it can be considered as a pump core assembly problems, such as the installation of misalignment, nozzle clearance is not correct, the pump core is not cleaned before assembly, organic solvents are not dried, pump oil is not enough or installed with poor quality pump oil and heating power adjustment is not correct.