1. Centrifugal pump should be selected according to the delivered liquid, and check the required performance, analysis of suction, discharge conditions, whether it is intermittent operation or continuous operation. Centrifugal pump should usually be at or close to the manufacturer's design pressure and flow rate. Run under conditions. The following review should be performed when the pump is installed;
1 The basic dimensions, position and elevation shall meet the design requirements. The foundation bolt must be properly and correctly fixed in the concrete foundation. The machine should not be missing, damaged or rusted.
2 According to the characteristics of the medium transported by the pump, the materials of the main parts, shaft seals and gaskets should be checked when necessary;
3 The leveling and correcting of the pump shall comply with the provisions of the equipment technical documents. If there is no regulation, it shall comply with the provisions of the current national standard "General Specification for Construction and Acceptance of Mechanical Equipment Installation Engineering";
4 All piping connected to the pump body, installation of fittings and cleaning of the oil pipelines shall comply with the relevant national standards.
2. Use of centrifugal pumps The commissioning of pumps should meet the following requirements:
1 The steering of the driver should be the same as the steering of the pump;
2 Find out the steering of the pipeline pump and the coaxial pump;
3 There should be no looseness in each fixed connection part, and the specification and quantity of lubricant added to each lubrication part shall comply with the provisions of the equipment technical documents;
4 Pre-lubricated parts should be pre-lubricated as required;
5 Each indicating instrument and safety protection device should be sensitive, accurate and reliable;
6 car should be flexible, no abnormalities;
7 The high-temperature pump should be preheated before test run. The temperature should rise evenly. The temperature rise should not exceed 50 °C per hour. The temperature difference between the surface of the pump body and the process pipeline with the working medium should not exceed 40 °C.
8 Set the connection device to eliminate the effect of temperature rise, set the bypass connection device to provide the cooling water source.
Operation should pay attention to the following points:
1 It is forbidden to run without water, do not adjust the intake of people to reduce the displacement, and prohibit the operation under too low flow;
2 Monitor the operation process, completely prevent the leakage of the stuffing box, and use new packing when replacing the stuffing box;
3 to ensure that the mechanical seal has sufficient flushing water flow, water-cooled bearings prohibit the use of excessive water flow;
4 do not use too much lubricant;
5 Perform inspections according to the recommended cycle. Establish operating records, including hours of operation, adjustment and replacement of packing, addition of lubricants and other maintenance measures and time. Pump suction and discharge pressure, flow, input power, lotion and Bearing temperature and vibration conditions should be measured regularly.
6 The host of the centrifugal pump is relying on the atmospheric pressure to pump water from a low point to a high point, but the atmospheric pressure can only support a water column of about 10.3m at most, so the host of the centrifugal pump cannot work 12 meters off the water surface.
3. Maintenance of Centrifugal Pumps 3.1 Analysis of Mechanical Seal Failure of Centrifugal Pumps Centrifugal pump shutdown is mainly caused by the failure of mechanical seals. Failure performance is mostly caused by leakage. The causes of leakage are the following:
1 Leakage of the static and dynamic ring sealing surface, mainly due to: flatness of the end surface, roughness does not meet the requirements, or scratches on the surface; there are particles between the end surfaces, causing the two ends can not be the same operation; installation is not in place, the way is not correct.
2 Compensation ring seal leakage, mainly due to: deformation of the gland, uneven preload; improper installation; seal quality does not meet the standard; seal selection is wrong.
The actual application results show that the most failure parts of the sealing elements are the end faces of the moving and stationary rings, the mechanical movement of the seals, and cracks on the static ring end faces are common failure phenomena. The main reasons are:
1 When the sealing surface gap is too large during installation, the flushing fluid is too late to take away the heat generated by the friction pair; the flushing fluid leaks from the gap between the sealing surfaces, causing the end surface to overheat and damage.
2 The liquid medium vaporizes and swells, so that the two ends are separated by the vaporization expansion force. When the two sealing surfaces are pressed together, the lubricating film is destroyed and the surface of the end surface is overheated.
3 poor liquid medium lubrication, coupled with operating pressure overload, the two sealing surface tracking rotation is not synchronized. For example, the high speed pump speed is 20445r/min, the sealing surface center diameter is 7cm, the pump speed is up to 75m/s, when There is a lag in the sealing surface that cannot follow the rotation and the instantaneous high temperature causes damage to the sealing surface.
4 Sealed rinsing liquid orifice plate or filter plugged, resulting in insufficient water volume, invalidating the seal.
In addition, the surface of the sealing surface glide, when the end surface of the gap when the sealing element caused failure, mainly due to:
1 The liquid medium is not clean, has tiny hard particles, slides the sealing surface at a very high speed, and scratches the end surface to fail.
(2) The coaxiality of the pump transmission parts is poor. After one revolution of the pump, the end face is shaken and rubbed once, and the running trajectory of the moving ring is not concentric, resulting in end face vaporization and overheating.
3 The frequent occurrence of the hydraulic characteristics of the liquid medium causes the pump group to vibrate, causing the sealing surface to misalign and fail.
Corrosion of the sealing element by the liquid medium, stress concentration, cooperation of soft and hard materials, erosion, auxiliary sealing O-ring, V-ring, concave ring and liquid medium are incompatible, deformation, etc. will cause mechanical seal surface damage and failure, so Comprehensive analysis of the damage to its form, to find the root cause, to ensure long-term operation of the mechanical seal.
3.2. Requirements after stopping the centrifugal pump 1 After the centrifugal pump is stopped, the population valve of the pump should be closed. After the pump is cooled, the valves of the auxiliary system are closed.
2 High-temperature pump parking should be performed according to the provisions of the equipment technical documents. After stopping, it should be half a turn for 20-30min, until the temperature of the pump body is reduced to 50°C.
3 When the cryogenic pump is stopped, when there is no special requirement, the pump should always be filled with liquid; the suction valve and the discharge valve should be kept in the normally open state; the cryopump with double-end mechanical seal, the liquid level controller and the sealing liquid in the pump sealing cavity The grouting pressure of the pump should be maintained.
4 The pump is easy to crystallize, easy to solidify, easy to sediment and other media, should stop blocking after stopping the pump, and flush the pump and pipeline in time with clean water or other media. 5 discharge the liquid accumulated in the pump to prevent corrosion and frost cracking.
3.3 Storage of Centrifugal Pumps 1 Pumps that are not yet mounted should be coated with an appropriate layer of anti-rust agent on the unpainted surface. Oil-lubricated bearings should be filled with proper fluid. Grease-lubricated bearings should only be filled. A grease, do not use mixed grease.
2 Pump the person for a short time to clean the liquid, rinse, suction line, discharge line, pump casing and impeller, and drain the pump casing, suction line and discharge line in the flushing fluid.
3. Clean the oil in the bearing housing and add clean oil. Thoroughly clean the grease and refill it with new grease.
4 Seal the intake and discharge ports, store the pump in a clean, dry place, protect the motor windings from moisture, and spray the inside of the pump housing with anti-rust and anti-corrosion fluids.
5 The pump shaft is rotated once a month to avoid freezing and to lubricate the bearings.
1 The basic dimensions, position and elevation shall meet the design requirements. The foundation bolt must be properly and correctly fixed in the concrete foundation. The machine should not be missing, damaged or rusted.
2 According to the characteristics of the medium transported by the pump, the materials of the main parts, shaft seals and gaskets should be checked when necessary;
3 The leveling and correcting of the pump shall comply with the provisions of the equipment technical documents. If there is no regulation, it shall comply with the provisions of the current national standard "General Specification for Construction and Acceptance of Mechanical Equipment Installation Engineering";
4 All piping connected to the pump body, installation of fittings and cleaning of the oil pipelines shall comply with the relevant national standards.
2. Use of centrifugal pumps The commissioning of pumps should meet the following requirements:
1 The steering of the driver should be the same as the steering of the pump;
2 Find out the steering of the pipeline pump and the coaxial pump;
3 There should be no looseness in each fixed connection part, and the specification and quantity of lubricant added to each lubrication part shall comply with the provisions of the equipment technical documents;
4 Pre-lubricated parts should be pre-lubricated as required;
5 Each indicating instrument and safety protection device should be sensitive, accurate and reliable;
6 car should be flexible, no abnormalities;
7 The high-temperature pump should be preheated before test run. The temperature should rise evenly. The temperature rise should not exceed 50 °C per hour. The temperature difference between the surface of the pump body and the process pipeline with the working medium should not exceed 40 °C.
8 Set the connection device to eliminate the effect of temperature rise, set the bypass connection device to provide the cooling water source.
Operation should pay attention to the following points:
1 It is forbidden to run without water, do not adjust the intake of people to reduce the displacement, and prohibit the operation under too low flow;
2 Monitor the operation process, completely prevent the leakage of the stuffing box, and use new packing when replacing the stuffing box;
3 to ensure that the mechanical seal has sufficient flushing water flow, water-cooled bearings prohibit the use of excessive water flow;
4 do not use too much lubricant;
5 Perform inspections according to the recommended cycle. Establish operating records, including hours of operation, adjustment and replacement of packing, addition of lubricants and other maintenance measures and time. Pump suction and discharge pressure, flow, input power, lotion and Bearing temperature and vibration conditions should be measured regularly.
6 The host of the centrifugal pump is relying on the atmospheric pressure to pump water from a low point to a high point, but the atmospheric pressure can only support a water column of about 10.3m at most, so the host of the centrifugal pump cannot work 12 meters off the water surface.
3. Maintenance of Centrifugal Pumps 3.1 Analysis of Mechanical Seal Failure of Centrifugal Pumps Centrifugal pump shutdown is mainly caused by the failure of mechanical seals. Failure performance is mostly caused by leakage. The causes of leakage are the following:
1 Leakage of the static and dynamic ring sealing surface, mainly due to: flatness of the end surface, roughness does not meet the requirements, or scratches on the surface; there are particles between the end surfaces, causing the two ends can not be the same operation; installation is not in place, the way is not correct.
2 Compensation ring seal leakage, mainly due to: deformation of the gland, uneven preload; improper installation; seal quality does not meet the standard; seal selection is wrong.
The actual application results show that the most failure parts of the sealing elements are the end faces of the moving and stationary rings, the mechanical movement of the seals, and cracks on the static ring end faces are common failure phenomena. The main reasons are:
1 When the sealing surface gap is too large during installation, the flushing fluid is too late to take away the heat generated by the friction pair; the flushing fluid leaks from the gap between the sealing surfaces, causing the end surface to overheat and damage.
2 The liquid medium vaporizes and swells, so that the two ends are separated by the vaporization expansion force. When the two sealing surfaces are pressed together, the lubricating film is destroyed and the surface of the end surface is overheated.
3 poor liquid medium lubrication, coupled with operating pressure overload, the two sealing surface tracking rotation is not synchronized. For example, the high speed pump speed is 20445r/min, the sealing surface center diameter is 7cm, the pump speed is up to 75m/s, when There is a lag in the sealing surface that cannot follow the rotation and the instantaneous high temperature causes damage to the sealing surface.
4 Sealed rinsing liquid orifice plate or filter plugged, resulting in insufficient water volume, invalidating the seal.
In addition, the surface of the sealing surface glide, when the end surface of the gap when the sealing element caused failure, mainly due to:
1 The liquid medium is not clean, has tiny hard particles, slides the sealing surface at a very high speed, and scratches the end surface to fail.
(2) The coaxiality of the pump transmission parts is poor. After one revolution of the pump, the end face is shaken and rubbed once, and the running trajectory of the moving ring is not concentric, resulting in end face vaporization and overheating.
3 The frequent occurrence of the hydraulic characteristics of the liquid medium causes the pump group to vibrate, causing the sealing surface to misalign and fail.
Corrosion of the sealing element by the liquid medium, stress concentration, cooperation of soft and hard materials, erosion, auxiliary sealing O-ring, V-ring, concave ring and liquid medium are incompatible, deformation, etc. will cause mechanical seal surface damage and failure, so Comprehensive analysis of the damage to its form, to find the root cause, to ensure long-term operation of the mechanical seal.
3.2. Requirements after stopping the centrifugal pump 1 After the centrifugal pump is stopped, the population valve of the pump should be closed. After the pump is cooled, the valves of the auxiliary system are closed.
2 High-temperature pump parking should be performed according to the provisions of the equipment technical documents. After stopping, it should be half a turn for 20-30min, until the temperature of the pump body is reduced to 50°C.
3 When the cryogenic pump is stopped, when there is no special requirement, the pump should always be filled with liquid; the suction valve and the discharge valve should be kept in the normally open state; the cryopump with double-end mechanical seal, the liquid level controller and the sealing liquid in the pump sealing cavity The grouting pressure of the pump should be maintained.
4 The pump is easy to crystallize, easy to solidify, easy to sediment and other media, should stop blocking after stopping the pump, and flush the pump and pipeline in time with clean water or other media. 5 discharge the liquid accumulated in the pump to prevent corrosion and frost cracking.
3.3 Storage of Centrifugal Pumps 1 Pumps that are not yet mounted should be coated with an appropriate layer of anti-rust agent on the unpainted surface. Oil-lubricated bearings should be filled with proper fluid. Grease-lubricated bearings should only be filled. A grease, do not use mixed grease.
2 Pump the person for a short time to clean the liquid, rinse, suction line, discharge line, pump casing and impeller, and drain the pump casing, suction line and discharge line in the flushing fluid.
3. Clean the oil in the bearing housing and add clean oil. Thoroughly clean the grease and refill it with new grease.
4 Seal the intake and discharge ports, store the pump in a clean, dry place, protect the motor windings from moisture, and spray the inside of the pump housing with anti-rust and anti-corrosion fluids.
5 The pump shaft is rotated once a month to avoid freezing and to lubricate the bearings.
Bathroom accessory includes a range of Floor Drain , Robe Hook , Glass Holder, Soap Holder , Toilet Paper Holder, Toilet Brush Holder, tower bar, Towel Shelf and etc.
Bathroom Accessory,Rose Gold Bathroom Accessory,Bath Hardware Accessories Set,Luxury Bathroom Accessories
Kaiping Jenor Sanitary Ware Co., Ltd , https://www.sanitaryjenor.com