ZJP series Roots vacuum pump is a positive displacement vacuum pump, also known as mechanical booster pump. It is one of the main air extraction equipments currently obtaining medium and high vacuum pumps. Its working principle is similar to that of Roots blowers. The rotor rotates synchronously in the pump casing to complete the process of suction and exhaust.
The advantages of ZJP series roots vacuum pumps are higher pumping rate at lower inlet pressure, and relatively high ultimate vacuum can be achieved. Because the pump is directly used for the main parts of pumping, such as no relative movement contact between the pump casing, the rotor and the end cover, the pump has stable running performance, long service life and low maintenance costs. At present, this kind of pump is widely used in vacuum smelting, vacuum welding, vacuum casting, vacuum spraying, vacuum drying, vacuum power experiments, and chemical processing, electric vacuum device manufacturing, and other vacuum processing in the vacuum range that this type of pump can achieve. .
For the chemical and pharmaceutical industries that need to extract a large amount of water vapor and solvents, our company has improved the sealing structure of the pump cavity and bearing cavity of the ZJ series Roots vacuum pump, greatly reducing the emulsification of the bearing cavity and gear cavity pump oil. The ZJP series roots vacuum pump is more suitable for removing a large amount of water vapor and solvents with a water ring vacuum pump. The product meets the relevant requirements of JB / T7674-2005 "Roots Vacuum Pump".
The ZJ / ZJP series products referred to in this manual mainly include the following specifications:
Roots vacuum pumps cannot be used alone. A fore vacuum pump must be connected in series. Only when the pressure in the pumped system is pumped by the fore vacuum pump to the inlet pressure that the roots vacuum pump can withstand can it start to work. .
1. The pumping work system of ZJP series Roots vacuum pump is non-oil-sealed, so it can completely avoid the phenomenon of oil return, oil leakage and oil fume pollution like oil-sealed vacuum pump.
2. The ZJP series Roots vacuum pump has a higher pumping rate at a lower inlet pressure, but it cannot be used alone. A fore vacuum pump must be connected in series. The pressure in the system to be pumped is pumped to the roots by the fore vacuum pump. Roots vacuum pumps only start working when the vacuum pump allows the inlet pressure (see Figure 1).
3. In addition to the above structural features, the ZJP series Roots vacuum pump with bypass valve also has automatic overload protection, but its suction performance is the same as that of the ZJ series Roots vacuum pump. Certain pumping rate and ultimate pressure. Therefore, the use of ZJP series vacuum pumps must also be equipped with a fore vacuum pump in series. After the fore vacuum pump reaches a certain pressure, the roots vacuum pump will start to work (see Figure 2). Because Roots vacuum pumps are not allowed to work under high pressure difference, when using Roots vacuum pumps, it is necessary to reasonably select the fore vacuum pump and install necessary protection devices. The foreline vacuum pump is generally an oil-sealed mechanical pump. If the ultimate vacuum is not high and the pumped object contains a large amount of water vapor, a water ring vacuum pump is recommended as the foreline pump.
1. Large pumping speed in a wide pressure range (1 ～ 1 × 104Pa). 2. The pump cavity is oil-free, which avoids oil vapor contaminating the vacuum system. 3. Small vibration and low noise. 4. The mechanical friction loss is small, so the driving power is small. 5. Easy maintenance and repair, low cost and long life. 6. Can remove suspicious gas. 7. Can not be used alone, must be equipped with foreline pump. It is not allowed to start under atmospheric pressure. It can be started after the foreline pump draws the inlet pressure of the roots pump to the allowable inlet pressure. The foreline pump is generally a water ring vacuum pump, an oil ring vacuum pump, and an oil-sealed mechanical pump. 8. Improved the characteristics of pumping water vapor and organic solvents, and solved the emulsification of bearing cavity pump oil.
1. The ZJ series roots vacuum pump uses a pair of 8-shaped rotors to maintain a certain gap in the pump casing, and rotates at the same speed in the reverse direction to generate the suction and exhaust effects (see Figure 3).
2. The ZJP series Roots vacuum pump with bypass valve is a derivative of the ZJ series Roots vacuum pump. Its working principle is the same as the ZJ series pump. It also uses a pair of 8-shaped rotors to maintain a certain gap in the pump cavity for constant speed. Reverse rotation results in suction and exhaust. The difference is that the inlet and exhaust ports of ZJP series pumps are connected. A deadweight valve is installed vertically on the channel. Its function is to reduce the pressure difference between the exhaust port and the intake port. When the product of the effective area of the valve and the weight of the valve head exceeds the deadweight of the valve head, the valve head automatically lifts the valve seat, so that the pressure difference between the exhaust port and the intake port is always maintained within a controllable value range. This value is based on The pump is designed to allow the highest pressure difference for reliable operation. Therefore, this valve is actually an overload automatic protection valve (see Figure 4)
3. The rotor is supported in the rolling bearing on the side cover of the pump casing. The pair of adjustable synchronous gears keeps the two rotors in relative position when rotating at high speed, and the end gap between the rotor and the end cover is based on the fixed end bearing. An adjustable metal gasket under the seat is used to ensure that the axial expansion of the rotor due to heat during operation only affects the gap at one end of the rotor.
4. The four sets of inner shaft seals in the end cover are to prevent the lubricant on both sides from penetrating into the pump cavity, and the oil seals at the shaft exit are to prevent gas from leaking into the pump.
5. In order to reduce temperature rise, in addition to the minimum two specifications, the rest are equipped with gear box cooler and shaft seal oil cooler.
6. The power of the motor is transmitted to the driving shaft through the coupling, and then to the driven shaft through the synchronous gear.
Seven, ZJ, ZJP series Roots vacuum pumps are horizontal structure design, using couplings and flanged motors directly connected.
The structure of the roots pump is shown in Figure 5. In the pump cavity, a pair of 8-shaped rotors are installed perpendicular to each other on a pair of parallel shafts, and a pair of gear belts with a transmission ratio of 1 act in a synchronous rotating motion in opposite directions to each other. There is a certain gap between the rotors and between the rotor and the inner wall of the pump casing, which can achieve high speed operation. Since the roots pump is a vacuum pump without internal compression, usually with a low compression ratio, a foreline pump is required. The ultimate vacuum of the roots pump depends not only on the structure and manufacturing accuracy of the pump, but also on the ultimate vacuum of the foreline pump. In order to increase the ultimate vacuum of the pump, Roots pumps can be used in series. The working principle of Roots pumps is similar to that of Roots blowers. Due to the continuous rotation of the rotor, the pumped gas is sucked into the space VO between the rotor and the pump casing from the suction port, and then discharged through the exhaust port. Since the VO space is completely closed after suction, the gas in the pump cavity is not compressed and expanded. However, when the top of the rotor is turned over the edge of the exhaust port and the VO space communicates with the exhaust side, because the gas pressure on the exhaust side is high, a part of the gas recoils into the space VO, which suddenly increases the gas pressure. When the rotor continues to rotate, the gas is discharged out of the pump.
罗茨真空泵的入口压强在6650Pa～2.66Pa范围内所测得的最大抽气速率。Note: 1. The pumping rate refersto the maximum pumping rate measured when the inlet pressure of the roots vacuum pump is in the range of 6650Pa to 2.66Pa when the recommended foreline pump is used.
2. The ultimate pressure refers to the stable pressure measured at the pump inlet with a compression vacuum gauge after fully pumping without any additional containers, and the pump port is sealed without air intake with the recommended foreline pump. Minimum value of partial air pressure. 3. The performance data shown in the table above are all obtained under the conditions of the recommended foreline pump. Users can choose different foreline vacuum pumps according to different situations, but their main performance indicators will change. 4. The weight values shown in the table above refer to the total weight when equipped with Y series motors.
Roots pumps have high temperatures on their casings, connecting pipes and accessories, which can cause injury when they come into contact with humans. Improper operation may cause serious injury to the human body due to internal or external transmission parts and driving equipment of the pump. The pump must not be operated with the inlet or exhaust cover removed. If moving parts of the pump are to be inspected or maintained, the control power supply must first be completely shut off and locked. When operating, lifting, installing, using, and servicing equipment, the equipment must be handled in strict accordance with the correct procedures.
I. Installation site:
1. Roots vacuum pumps should be installed in bright, dust-free buildings. 2. Roots vacuum pump installation temperature is 5 ～ 40 ℃. 3. There must be sufficient room around the roots vacuum pump to facilitate daily inspection, maintenance and disassembly.
Second, basic engineering
1. Roots vacuum pump and foreline pump are installed on the same frame to form a unit and then installed on the concrete foundation. Large pumps must be installed separately and poured on the concrete foundation. 2. Determine the compression area and depth of the concrete foundation according to the weight of the roots pump and the pressure resistance of the foundation. 3. In order to embed the foundation bolts in the concrete, sufficient holes must be left according to the position of the foundation holes when the concrete foundation is poured. 4. Make the base surface level.
Roots vacuum pump must be installed on a horizontal foundation surface. If the foundation surface is not flat, it will affect the normal operation of the pump. 1. Make the wooden frame according to the position of the bottom hole, fix the foundation bolt to the wooden frame, put it into the reserved hole, and then pour concrete into the reserved hole. Leave it for several days, and remove the wooden frame after the concrete hardens . 2. Put the roots vacuum pump on the foundation, use a spirit level to correct the level, use uneven metal pads to fill the uneven parts, tighten the foundation bolts, and fill the bottom gap with cement.
Fourth, pipeline installation
Note: If welding slag and other foreign matter enter the pump during the work, it will cause serious damage or damage to the roots pump and foreline pump. Therefore, the pipeline must be cleaned strictly before installation. During the working process, it is strictly forbidden to inhale the gas with particles and dust, so the corresponding filtering device must be equipped. 1. There is no foreign matter such as welding slag, impurities in the inlet and outlet pipes, and there is sufficient ventilation capacity. 2. An elastic pipe must be installed in the connecting pipe from the roots vacuum pump outlet to the foreline pump inlet to reduce the impact of the foreline pump vibration on the roots vacuum pump. 3. In order to shorten the pre-pumping time, in the general system, in addition to the inlet of the foreline pump is connected to the exhaust port of the roots vacuum pump, bypass pre-pumping pipes and valves need to be installed. 4. In order to prevent oil return or water back when the foreline pump is stopped (when the foreline pump is a water ring vacuum pump), an air release valve or check valve should be installed on the intake pipe of the foreline pump. 5. The pipe connection flange must be sealed with an O-shaped rubber seal and coated with vacuum cockroach grease. The entire vacuum system must be sealed. 6. The cooling water inlet and outlet of the pump should be connected to the pipeline, and a valve should be installed on the water inlet pipe to adjust the water volume.
Five, electrical equipment installation
1. Roots vacuum pump can only work within the specified inlet pressure range. When the current pump stops working, the Roots vacuum pump must stop working at the same time. Therefore, the installation of electrical equipment must have interlocking and necessary automatic protection. 2. The connection line of the motor must make the pump turn in the direction indicated by the arrow. 3. The small pump can be started directly, and the large pump must be installed with a starter.
I. Preparations before starting
1. Open the cooling water inlet valve and check if the cooling water is smooth. 2. Fill out the shaft seal cavity and the oil cup with lubricating oil, add the lubricating oil in the gear box and bearing box to the height of 2/3 ～ 3/4 of the diameter of the oil window, and use No. 1 vacuum oil for lubricating oil. 3. When used under the following conditions, corresponding measures must be taken: a: When there is dust or particles in the inhaled gas, a dust collector or filter should be installed in front of the air inlet; b: If the inhaled gas is corrosive, neutralization measures must be taken; c: When the suction gas contains water vapor, and the selected foreline pump is an oil-sealed mechanical pump, the foreline pump should be equipped with a gas ballast device. When there is too much water vapor, a condenser must be installed.
Second, the starting procedure:
1. Start the foreline pump. 2. Open the valve on the foreline pump pre-pump bypass pipe and the valve on the roots vacuum pump intake pipe. 3. When the pressure in the system reaches the inlet pressure allowed by the Roots vacuum pump, close the valve on the bypass pipe. Restart the Roots vacuum pump; if bypass pipes and valves are not installed, the Roots vacuum pump should be started after the pressure in the system reaches the inlet pressure allowed by the Roots vacuum pump; if an automatic control device is used, the starting process can be automated . 4. According to the actual situation of the vacuum system, if it is a small sealed system, the Roots vacuum pump can be started immediately after starting the foreline pump; if it is a larger vacuum system, although the Roots vacuum pump with a bypass valve has overload protection Capacity, but considering the economy, the Roots vacuum pump should be started after the foreline pump has pumped to a certain pressure.
Third, the attention points in operation:
1. It must be used in strict accordance with the technical specifications of Roots vacuum pumps. Under normal circumstances, the inlet pressure of Roots vacuum pumps is below 133 × 102Pa, and its maximum inlet pressure should not exceed its allowable maximum inlet pressure. If it is exceeded, although the ZJP Roots vacuum pump with bypass valve can be automatically protected, this protection is only an overload protection for the motor. Pumps can also fail due to overheating if they are operated for longer periods than the maximum allowable inlet pressure. 2. Pay attention to the load of the motor and the temperature rise of the pump at all times. Under normal circumstances, the maximum temperature rise of the pump must not exceed 40 ° C, and the maximum temperature must not exceed 80 ° C. 3. There should be no abnormal vibration during operation. 4. If you find that the motor is overloaded during operation, the temperature is too high, the sound is abnormal, or the vibration is too large, you should immediately stop the machine and check the cause, and remove the fault in time.
Fourth, shutdown procedures:
1. Close the foreline oil-sealed mechanical pump gas ballast valve (if the foreline pump is open when the ballast valve is in use). 2. Close the roots vacuum pump inlet valve. 3. Stop the pump step by step: Stop the Roots vacuum pump first, and then stop the foreline pump. It is forbidden to mistake the shutdown sequence. 4. While stopping the foreline pump, deflate the inlet of the foreline pump immediately. 5. Close the cooling water inlet valve. 6. If you need to stop using the pump for a long time, or to prevent the pump body from freezing in winter, you must drain all the cooling water in the pump.
I. Regular inspection
1. Daily inspection: a: Check the oil level: too much oil will increase the temperature, and too little oil will cause poor lubrication; b: Check temperature: Check the temperature of each part of the pump with a thermometer; c: Check the motor load: Measure the motor load with a power meter or current and voltmeter. 2. Monthly check: Whether the coupling and gasket are damaged or loose. 3． Check every three months: Whether the lubricant in the gearbox has deteriorated. 4． Check every six months: a: Whether the lubricant in the front cover bearing box has deteriorated; b: Whether the oil seal is worn; 5． Checked annually: a: Whether the bearing is worn; b: Whether the piston ring and piston ring bush are worn; c: Whether the slight wear of the gear will affect the normal operation of the rotor and whether it needs to be adjusted.
When disassembling and reassembling the roots vacuum pump, it must be performed in the following order: 1. Before disassembly, the clearance of each part of the rotor should be measured and recorded. 2. Try to avoid hitting with a heavy hammer. The removed parts must not be injured and should be properly stored. 3． Record the replacement reasons and usage of the parts that need to be replaced in detail. 4． Before reassembly, all parts must be cleaned and the burrs repaired. 5． The static sealing surface without gasket or gasket is evenly coated with "106" silicone rubber coating; the rubber seals used for static sealing should be coated with vacuum crocodile grease; ZJP type with bypass valve vacuum pump bypass valve Rings and surfaces must not be coated with any grease. 6. Adjust the clearance of each part of the rotor according to the clearance list (Table 4). 7. Leak test must be performed after all installation. 8. After reassembly, trial operation and necessary performance tests must be performed, and they can be put into use after normal.
Table 3: Fault analysis and troubleshooting table
Extreme pressure is not high
Leaks in pipes and systems
System leak detection
Leak in the pump
Leak test the pump
Foreline pump ultimate pressure drops
Repair or replace the foreline pump
The lubricant is too dirty or does not match the grade
Oil seal wear
Replace oil seal
Leak at bypass valve
Cleaning the bypass valve
Insufficient pumping speed
Insufficient pipeline conductivity
Increase pipeline conductivity
Foreline pump speed drops
Repair or replace the foreline pump
Leak at bypass valve
Cleaning the bypass valve
Inlet pressure is too high
Adjust and control inlet pressure
The rotor end face is in contact with the cover
Adjust rotor end clearance
Foreline pump returns oil into pump cavity
Install anti-oil back device
Bypass valve blocked, making outlet pressure too high
Cleaning the bypass valve
The foreline pump selected has insufficient pumping speed, resulting in excessive compression
Reselect the foreline pump
Inlet pressure is too high
Adjust and control inlet pressure
Unblocked cooling water
Gearbox with too much lubricant
Adjust the amount of oil
The rotor is in contact with the pump casing
Gear, bearing, oil seal poor lubrication
Ensure proper oil volume and good lubrication
The position of the guide gear and the rotor deviates, causing the rotor to collide
Adjust position and ensure clearance
Inlet pressure is too high
Adjust and control inlet pressure
Damage to gear due to overload or poor lubrication
Bearing and gear wear early
Safety protection device and accident handling
First, if Roots vacuum pump is used to pump flammable, explosive, toxic and corrosive media, corresponding safety protection measures must be taken.
2. Improper application, incorrect operation and maintenance, or non-professional operation is not allowed, will cause serious personal injury or property damage. Especially in the case of using or transporting high temperature, high pressure and dangerous media.
3. The basic plan for equipment installation and all work related to lifting, installation, commissioning, maintenance and repair of the equipment must be performed by professionals and inspected by skilled persons.
4. Under special circumstances, if the equipment is used in more demanding non-industrial fields, then additional protection measures provided on site must be used to ensure that these requirements are met during installation.
5. If it is used in flammable and explosive places such as coal mines, it must be equipped with an explosion-proof motor of the corresponding level; if a triangular transmission belt is used, a flame-retardant and antistatic triangular transmission belt should be used!
I. Precautions for lifting and transportation
1. The vacuum pump lifting method should be appropriate. 2. The lifting capacity of the spreader and lifting equipment should be adapted to the weight of the vacuum pump. 3. The spreader should be long enough, that is, the included angle of the spreader should be less than 900. 4. Select the appropriate lifting point. 5. The spreader must be placed correctly to ensure stable lifting. 6. Please check the integrity of the spreader. 7. Please confirm the lifting capacity of the lifting equipment!
1. If the Roots vacuum pump is to be stopped for a long time, first drain its working fluid. 2. If the pump has rust-prone parts and should be stopped for two weeks or more, anti-rust measures should be adopted. Make sure that the vacuum pump is completely emptied, and rinse with antiseptic first, and then evacuate and dry it. You can also install another vacuum pump on the exhaust side of the vacuum pump to dry it out. dry. If it is not easy to dry, the impeller must be rotated every two weeks to make sure that the impeller and the disc will not rust together. 3. The above process should be well-documented in order to make corresponding correct arrangements when the pump restarts operation.