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Roots vacuum pump

Min.Order Quantity: 1 Set/Sets Roots vacuum pump

Supply Ability: 400~700 Set/Sets per Month Roots vacuum pump

Payment Terms: L/C,T/T,

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 1. ZJ series roots vacuum pump structure principle and operating characteristics

(I) structure principle:
1, ZJ series roots vacuum pump, is a positive displacement vacuum pump, it is the use of a pair of 8 sub-rotor in the pump shell to maintain a certain clearance, equal speed reverse rotation and produce suction and exhaust (see figure 1).
2, ZJP type with overflow valve type roots vacuum pump is what ZJ had roots vacuum pump derived products, extraction principle, like what ZJ had type pump, use a pair of 8 rotor to keep a certain gap in the pump shell, a constant speed reverse rotating of suction and exhaust function, the difference is connected ZJP type pump into the vent, vertical device with a dead weight on the channel valve (see figure 1 (a)), its effect is when the outlet and inlet pressure differential and valve's effective area more than the product of weight of valve head, valve will automatically open the valve seat, make the pressure difference between the outlet and inlet remain within a controlled numerical, This value is the maximum allowable pressure difference for reliable operation of the designed pump. Therefore, this kind of valve is actually an overload automatic protection valve.
3, two rotor are bearing on the end cover of the rolling bearing in the pump shell side, relying on a pair of synchronous gears adjustable make two rotor rotates at high speed has always maintained a certain position, but the end clearance between rotor and end cover is depends on the fixed end bearing the adjustable metal gasket to ensure below, make the pump rotor because of the heat at work only to one side.
4, the end cover of the four groups of internal shaft seals is to prevent both sides of the lubricating oil into the pump shell, out of the shaft oil seal is to prevent gas leakage into the pump.
5, in order to reduce the pump temperature, in addition to the minimum two specifications of the pump, are equipped with gear box cooler and shaft oil seal cooler.
6. The power of the motor is transmitted to the driving shaft through the coupling, and then driven to the driven shaft through the synchronous gear transmission.
7, ZJ, ZJP series roots vacuum pump are made of horizontal structure, using coupling and motor direct connection.

(ii) ZJ series roots vacuum pump features:
What ZJ had series roots vacuum pump is one of the biggest advantages in low inlet pressure has high extraction rate, but it cannot be used alone, there must be a front stage vacuum pump series, the pressure in the stay by the pumping system is the front-end of the roots vacuum pump vacuum pump to allow inlet pressure, the roots vacuum pump can begin to work (see chart 1), and in the general case, roots vacuum is not allowed to work when high pressure difference, otherwise it will overload and overheating and damage, so when using the roots vacuum pump must be reasonably choose the former vacuum pump, install the necessary protection equipment.
ZJP type roots vacuum pump with overflow valve has the biggest characteristic of automatic overload protection, and the pumping performance and ZJ type roots vacuum pump are the same, that is, at a lower inlet pressure with a higher pumping rate. But because roots vacuum pump is a kind of dry clearance sealing mechanism, in order to obtain a certain extraction rate and limit pressure, but also must reduce the pressure of the front stage, reduce the reflux. Therefore, when using, there must be a front stage vacuum pump in series, and to the front stage vacuum pump pumping to a certain pressure after the roots vacuum pump began to work, so as to be the most economical. (see figure 2a)
The former vacuum pump is generally oil seal mechanical pump, but if the limit pressure requirements are not high, can choose other forms of crude vacuum pump as the former pump. Especially in the extraction of gas containing a lot of water vapor, the water ring vacuum pump as the former stage pump is very ideal, of course, the ultimate pressure can be achieved to the strength of the lower.

Ii. Installation instructions of ZJ series roots vacuum pump

(I) installation site:

1. Roots vacuum pump shall be installed in a bright and dust-free building.

2, roots vacuum pump installation environment temperature for 5 to 40 ℃.

3. Sufficient space shall be left around roots vacuum pump for daily inspection, maintenance, disassembly and assembly.

(ii) basic engineering:

1, small and medium-sized pumps can be installed on the same frame with the front stage pump and other components of the unit before installation on the concrete foundation, large pumps must be installed separately, pouring concrete foundation.

2. Determine the compression area and depth of concrete foundation according to the weight of roots vacuum pump and the pressure resistance of foundation.

3. In order to embed foundation bolts in concrete, sufficient holes must be set aside according to the position of the base hole when pouring concrete foundation.

4. Make horizontal foundation surface.

(iii) installation:

1. Make a wooden frame according to the position of the base hole, fix the foundation bolt on the wooden frame, put it into the reserved hole, then pour concrete into the reserved hole, place the number, and remove the wooden frame after the concrete is hardened.

2. Put roots vacuum pump on the foundation, check the level with the level meter, the uneven part is hard with the metal gasket, tighten the foundation bolt, and fill the gap of the bottom surface with cement.

(iv) pipeline installation:

1. There is no welding slag, impurities or other foreign matter in the inlet and outlet gas pipeline, and there is enough channel capacity.

2. A stretch of elastic pipe shall be installed in the connecting pipe from the outlet of roots vacuum pump to the inlet of the front stage pump to reduce the impact of the vibration of the front stage pump.

3. In order to shorten the pre-pumping time in general systems, in addition to connecting the inlet of the front-stage pump with the outlet of roots vacuum pump, bypass pre-pumping pipes and valves should be installed. Roots vacuum pump with overflow valve can work under high inlet pressure, so it is not necessary to install pre-pumping pipe and valve.

4. In order to prevent the return of oil or water when the front pump stops, the inlet pipe of the front pump should be equipped with a vent valve or a check valve.

5. The pipe connecting flange must be sealed with a 0-shape rubber sealing ring and coated with vacuum cocker grease, and the whole vacuum system must be sealed without leakage.

6, the pump cooling water inlet and outlet should be connected to the pipeline, and the inlet pipe installed with a valve, adjust the amount of water.

(v) electrical installation:

1. Because roots vacuum pump can only work within the specified inlet pressure range, and when the current stage pump stops working, roots vacuum pump must stop working at the same time. Therefore, electrical equipment must have interlock and necessary automatic protection.

2, the motor wiring needs to make the pump steering in line with the direction indicated by the arrow.

3, small pump can be started directly, large pump must be equipped with starter.


ZJ series roots vacuum pump instructions

(I) preparation before starting:

1. Open the inlet valve of cooling water and check whether the cooling water is unblocked.

2. Fill the outer shaft seal cavity and oil cup with lubricating oil, add the lubricating oil in the gear box and bearing box to the oil window diameter 3/4 height, and use no. 1 vacuum pump oil for lubricating oil.

3. When used in the following situations, appropriate measures must be taken:

A) dust remover or filter shall be installed before the suction port when dust or particles are inhaled into the gas;

B) if the inhaled gas is corrosive, neutralization measures must be taken;

C) if the inhaled gas contains water vapor, when the front-line pump selected is the oil seal mechanical pump, the oil seal mechanical pump should be equipped with gas ballast device, when the water vapor is too much, the condenser must be installed.

(ii) starting procedure:

1. Start the pre-stage pump

2. Open the valve on the pre-pumping bypass pipe of the front stage pump and the valve on the exhaust pipe of roots vacuum pump.

3, to reach the roots vacuum pump pressure in systems that would allow the inlet pressure, will be closed on the by-pass pipe valve, restart the roots vacuum pump, if no bypass pipes and valves, stay in the system pressure is allowed by the roots vacuum pump inlet pressure, you can start the roots vacuum pump, if adopts the automatic control device, is the starting process can be automated.

4. According to the actual situation of vacuum system, if it is a small sealing system, roots vacuum pump can be started after starting the front-stage pump. If it is a larger vacuum system, although the roots vacuum pump with overflow valve has overload protection, but considering the economy, the roots vacuum pump should be started after the pre-stage pump is pumped to a certain pressure.

(iii) points for attention during operation:

1. The operation must be strictly in accordance with the technical specifications of roots vacuum pump. Under normal circumstances, the inlet pressure of roots vacuum pump is below 1330Pa, and its maximum inlet pressure shall not exceed its allowable maximum inlet pressure. If exceed, ZJP with overflow valve roots vacuum pump can automatically protect, but this protection, only for the motor overload protection. The pump may also fail due to overheating if it is operated for a long time in excess of the allowable maximum inlet pressure.

2, pay attention to the temperature rise of the load of the motor and pump parts, under the condition of normal operation, the highest temperature rise of the pump shall not exceed 40 ℃. The highest temperature should not exceed 80 ℃.

3. There should be no irregular abnormal vibration in operation.

4. If it is found that the motor is overloaded, the temperature rises are too high, the sound is abnormal, the vibration is large, etc., it shall immediately stop the machine to check the reasons and troubleshoot the faults.

(iv) shutdown procedure:

1, close the front stage oil seal mechanical pump air valve (if the front stage pump in use is open air valve).

2. Close the air inlet valve of roots vacuum pump.

3, stop the mechanical booster pump step by step, the last stop before the stage pump, it is strictly prohibited to stop the wrong procedures.

4, in the stop of the front stage pump at the same time, immediately forward stage pump inlet gas.

5. Close the cooling water inlet valve.

6. If it is necessary to stop using for a long time, or to prevent freezing and cracking in winter, the remaining water in the cooling water jacket must be drained.


Iv. ZJ series roots vacuum pump maintenance

(I) regular inspection:

1. Daily inspection:

A) oil level inspection: too much oil increases the temperature and too little oil leads to poor lubrication.

B) temperature check: check the temperature of each part of the pump with thermometer.

C) motor load inspection: motor load is measured by power meter or current and voltmeter.

2. Monthly inspection:

Whether the coupling and gasket are damaged and loose.

3. Check every 3 months:

Whether the lubricating oil in the gearbox deteriorates.

4. Check every 6 months:

A) whether the lubricating oil in the front cover bearing box deteriorates.

B) wear of piston ring and piston ring bushing.

C) whether the minor wear of gears has an impact on the normal operation of the rotor and whether it needs to be adjusted.

(ii) disassembling and assembling:

When the booster pump is disassembled and reassembled, it shall be carried out according to the following matters needing attention:

1. Before disassembly, measure and record the clearance of each part of the rotor.

2. Avoid hammering with a heavy hammer as far as possible. The parts removed shall not be damaged.

3. Make a detailed record of the reasons for replacement and use of parts that need to be replaced.

4. All parts shall be cleaned and burr polished before re-assembly.

5. "106" silicone rubber coating for static sealing surface without gasket liner or sealing ring. Use a clean sealed rubber seal coated with vacuum cocker grease. ZJP type vacuum pump overflow valve with overflow valve sealing ring and plane shall not be coated with renke grease.

6. Adjust the clearance of each part of the rotor according to the clearance list.

7. Leak detection shall be carried out after all of them are installed.

8. Test run and necessary performance test shall be carried out after reinstallation, and the device shall not be installed and used until it is normal.

model Pumping speed
(L / sec)
Ultimate pressure
Starting pressure
Maximum pressure difference
Rotating speed
(transfer / minute)
Motor Power
Caliber (mm) weight
Recommended for use
Foreline pump model
import Export
ZJ-30 30 6×10-2     1450 1.1 50 40 66 2X-4
ZJP-30 5×10-2 101326 8000 75
ZJ-70 70 6×10-2     2900 1.1 80 50 87 MH-2/30
ZJP-70 5×10-2 101326 6000 100
ZJ-150A 150 6×10-2     2900 2.2 100 100 198 MH-2/50
ZJP-150 5×10-2 101326 6000 215
ZJ-300 300 6×10-2     2900 4 150 150 490 MH-2/100
ZJP-300 5×10-2 101326 5000 480
ZJ-600 600 6×10-2     2900 5.5 150 150 490 MH-2-150
ZJP-600 5×10-2 101326 4000 503
ZJ-1200A 1200 6×10-2     2900 11 300 300 1550 MH-2/150Two sets
orMH-2/200Two sets
ZJP-1200 5×10-2 101326 3000 1580


Note: 1. Extraction rate refers to the maximum extraction rate measured within the range of 6650pa -- 2.66pa at the inlet pressure of roots vacuum pump under the condition of using the recommended front-stage pump.

2. The ultimate pressure refers to the lowest value of the stable air partial pressure measured at the pump inlet by the compression vacuum gauge after full air extraction without any additional vessel or pump mouth seal under the condition of the recommended pre-stage pump.

3. The performance of the above table is obtained under the condition of using the recommended front-stage pump. Users can choose different front-stage vacuum pumps according to different conditions, but their main performance indicators will change.

4. Weight coefficient: the total weight of y-series motors.

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