What ZJ had series roots vacuum pump manufacturing, a kind of rotation without internal compression varactor type vacuum pump, also known as mechanical booster pump, its advantage is in low inlet pressure has high extraction rate, it is currently available in one of the main extraction equipment, high vacuum, its working principle are similar to those of roots blower, mainly composed of a pair of synchronous high-speed rotating “8” glyph of rotor and two semicircle pump cavity.ZJ series Roots vacuum pump can not exhaust separately. It must be used in series with the front pump (such as slide valve pump, rotary vane vacuum pump, water ring vacuum pump, oil ring pump, etc.). It can not start working until the pressure in the pumping system is pumped to the pressure that Roots vacuum pump can accept by the front vacuum pump, otherwise it will be damaged by overload and overheating. The vacuum degree of the front stage pump can be improved by connecting ZJ series Roots vacuum pump in series in front of the intake port of the front stage pump, and the pumping rate can be greatly increased within the effective range. The limit pressure of ZJ series Roots vacuum pump is determined by the front pump. The data in the technical parameter table are the low limit pressure of standard configuration (with double-stage oil seal mechanical vacuum pump).
ZJ series Roots vacuum pumps are widely used in vacuum casting, vacuum smelting, vacuum degassing, vacuum coating, chemical and pharmaceutical industries for vacuum distillation and vacuum drying because of their large pumping speed in a wide pressure range (1-1 *104pa) and insensitivity to dust and water vapor in the extracted gas.
1. Improvement of structure
The bearing chamber of Roots pump is usually cooled and lubricated by lubricating oil. If this part of the pump oil is emulsified, it must be replaced immediately. Otherwise, it will cause the bearing corrosion and cause the vibration and noise of the pump to increase. If the bearing is not replaced in time, it will aggravate the wear of the gear and cause the damage of the whole pump.
2. In view of the old problem that Roots vacuum pump is easy to emulsify when pumping a large amount of water vapor and organic solvents with water distribution ring vacuum pump, our company has made an important improvement on the sealing structure of pump chamber: FPM or PTFE flexible seals are added between pump chamber and bearing chamber to seal pump chamber and bearing chamber, thus solving the emulsification phenomenon of Roots pump oil. The sealing structure has been fully verified after many years of use.
3. Treatment of inner surface of pump chamber
When Roots vacuum pump is pumping out a large amount of water vapor and chemical solvents, the surface of the rotor and pump chamber is prone to rust. It often appears that the rotors and pump chambers are corroded and can not run without Roots pump in a few days after commissioning; or when the pump is opened again after a long period of shutdown; or when the rotors and pump chambers are corroded after a long period of use, the performance of the pump is affected.
In view of the above phenomena, our company has nickel plated all the rotors of Roots vacuum pumps and the inner walls of pump chambers. After nickel plating, the corrosion resistance and rust resistance of Roots vacuum pumps have been greatly improved.
4. Improvement of Rotor Profile
The meshing clearance between the rotors is a major factor affecting the performance of Roots vacuum pump. The meshing clearance between the rotors of Roots vacuum pump should be uniform and small on the premise of ensuring the stable operation of the pump. Because of the deviation between the theoretical profile of Roots rotor and the actual profile, the profile of Roots rotor processed by engineers of our company is more uniform, which fully guarantees the performance of the pump. Through comparative test, the performance of the improved product is comparable to that of the imported product.
All castings are made of metal model and resin sand. The surface quality of the castings is good. No need to be greased. Direct painting is more conducive to heat dissipation of the pump.
All bearings are NSK imported bearings, which fully guarantees the operation stability and service life of the pump.
All gears are of grade 6 or above of the national standard. All gears are quenched at high frequencies. The gear grinder grinds the teeth to ensure the stable operation of Roots pump and low noise.
ZJ series Roots vacuum pump surface all sprayed with high quality epoxy paint, acid and alkali resistance, high temperature resistance, durable color.
Technical parameter table of ZJ series Roots vacuum pump:
|1stage piston pump as backing pump||5×10-2|
|2 stage piston pump as backing pump||1×10-1|
|Max. allowable diff. pressure（Pa）||8×103||5×103|
|Motor rotary speed（RPM）||3000|
|Suitable motor power（kW）||2.2||4||7.5||11|
|Cooling water consumption（L/h）||120||150|
|Vacuum pump oil||100#|
ZJ series Roots vacuum pump structure:
1. Roots Vacuum Pump General Structure
The layout of the pump body of Roots vacuum pump determines the overall structure of the pump. At present, there are roughly three types of Roots vacuum pumps at home and abroad:
(1) The horizontal arrangement of the intake and exhaust ports of the vertical structure, the assembly and connection of the pipelines are more convenient. But the center of gravity of the pump is high and its stability is poor at high speed, so this type of pump is mostly used in small pumps.
(2) The intake port of the horizontal pump is on the top and the exhaust port is on the bottom. Sometimes in order to facilitate the installation and connection of the vacuum system pipeline, the exhaust outlet can be connected from the horizontal direction, that is, the direction of intake and exhaust is mutually perpendicular. At this time, the exhaust outlet can be opened in both left and right directions. In addition to one end of the exhaust pipe, the other end is blocked or connected with a bypass valve. The pump has low center of gravity and good stability at high speed. Generally large and medium-sized pumps use this structure.
(3) The two rotor shafts of the pump are installed vertically with the horizontal plane. The assembly clearance of the structure is easy to control, the assembly of the rotor is convenient, and the area of the pump is small. But the center of gravity of the pump is high and the gear disassembly and assembly is inconvenient, and the lubrication mechanism is relatively complex. It is only found in foreign products.
2. Roots Vacuum Pump Driving Mode
The two rotors of Roots vacuum pump are synchronized by a pair of high precision gears. The drive shaft is connected with the motor through a coupling. There are two main types of transmission structure arrangement: one is that the motor and the gear are placed on the same side of the rotor as shown in the figure. The driven rotor is driven directly by the end gear of the motor, so that the torsional deformation of the active rotor shaft is small, and the clearance between the two rotors will not change because of the torsional deformation of the active shaft, so that the clearance between the rotors is uniform in the course of operation. The major drawbacks of this transmission mode are as follows: a. There are three bearings on the drive shaft, which increase the difficulty of processing and assembling Roots vacuum pump, and the disassembly and adjustment of gears are inconvenient; B. The overall structure is not symmetrical, and the gravity center of Roots vacuum pump is biased to the side of motor and gear box.
The other is that the motor and the transmission gear are installed on both sides of the rotor respectively. This form makes the whole structure of Roots vacuum pump symmetrical, but the torsional deformation of the driving shaft is large. In order to ensure that the clearance of the rotor is uniform in the process of operation, it is required that the shaft should have sufficient stiffness and the connection between the shaft and the rotor should be tightened (at present, the rotor and the shaft are welded or cast into one structure). This kind of structure is very convenient to disassemble and assemble, so it is widely used.
Roots Vacuum Pump Products Pictures: