(a), structure principle:
1. Roots vacuum pump is a volumetric vacuum pump. It uses a pair of 8 sub-rotors to maintain a certain clearance in the pump casing, and it can generate the suction and exhaust functions by counter-rotating at the same speed.
2. ZJP type relief valve Roots vacuum pump is a derivative product of ZJ Roots vacuum pump. The pumping principle is the same as that of ZJ pump. It also uses a pair of 8-shaped rotor to maintain a certain clearance in the pump casing for constant speed. The reverse rotation to produce the effect of suction and exhaust, the difference is ZJP-type pump intake and exhaust connections, in the channel vertically equipped with a self-weight valve, its role is when the exhaust port and the inlet pressure When the product of the difference and the effective area of the valve exceeds the weight of the valve head, the valve head automatically opens the valve seat so that the pressure difference between the exhaust port and the intake port is always maintained within a controllable value. This value is designed The maximum pressure difference allowed for reliable operation of the pump. Therefore, this kind of valve is actually an overload automatic protection valve.
3. The two rotors are supported in the rolling bearing on the side cover of the pump casing. The two rotors always maintain a certain mutual position during high-speed rotation by means of a pair of adjustable synchronous gears, and the end face between the rotor and the end cover. The clearance is ensured by the adjustable metal gasket under the fixed-end bearing seat, so that the pump can only expand to one side due to heat during operation.
4. The four sets of inner shaft seals in the end cap are designed to prevent the oil from entering the pump casing on both sides. The oil seal at the outlet is to prevent the gas from leaking into the pump.
5, in order to reduce the pump temperature, in addition to the smallest two specifications of the pump, are equipped with a gear box cooler and outlet shaft seal cooler.
6. The power of the motor is transmitted through the coupling to the drive shaft and then through the synchronous gear drive driven shaft.
7, Roots vacuum pumps are made of horizontal structure, using the coupling and the motor directly.
(B), Roots vacuum pump features:
The greatest advantage of the Roots vacuum pump is that it has a higher pumping rate at lower inlet pressures, but it cannot be used alone. There must be a foreline pump connected in series until the pressure in the pumped system is pumped to the Roots by the fore pump. When the vacuum pump allows the inlet pressure, the Roots vacuum pump can start working, and under normal circumstances, Roots vacuum does not allow the high pressure difference to work, otherwise it will be overloaded and overheated and damaged, so when using a Roots vacuum pump must be reasonably selected before Vacuum pump, install necessary protective equipment.
ZJP type with overflow valve Roots vacuum pump has the biggest feature of automatic overload protection, and the pumping performance is the same as ZJ Roots vacuum pump, that is, it has higher pumping rate at lower inlet pressure. However, because the Roots vacuum pump is a dry gap sealing mechanism, in order to obtain a certain pumping rate and ultimate pressure, the pressure at the fore stage must also be reduced to reduce the back flow. Therefore, when using, there must be a foreline vacuum pump in series, and the Roots vacuum pump will start to work after the vacuum pump is pumped to a certain pressure, which is the most economical.
The foreline vacuum pump is generally an oil seal mechanical pump, but if the extreme pressure requirement is not high, other rough vacuum pumps may be used as the foreline pump. Especially when extracting gases containing a large amount of water vapor, it is ideal to use a water ring vacuum pump as a foreline pump. Of course, the ultimate pressure that can be achieved is lower.
No comments:
Post a Comment