Chemical pump installation and use precautions of the main points of installation and use of the valves of chemical pump

Chemical pump installation and use precautions of the main points of installation and use of the valves of chemical pump

Chemical pump is the chemical industry to use the best products, there are several types of centrifugal chemical pump according to the material is divided into polypropylene, fluorine plastic, stainless steel, according to the pump body structure is divided into direct connection type, joint shaft type, vertical, horizontal several, according to the actual demand can refer to choose the right products. The pump is the introduction of foreign advanced technology developed by our company can transport containing solid particles, easy crystallization of the medium, temperature resistance, corrosion resistance, no blockage.
Installation process:
1, according to the basic specifications to do a good job of concrete, together to bury the foundation screw of the chemical pump.
2. Check the chemical pump and motor before installation. Each part should be in good condition, and there should be no dirt inside the chemical pump.
3, the chemical pump overall to the basic, in the bottom and the basic middle of the shock absorber block, according to the adjustment of the shock absorber block, find a good level of the chemical pump. After the adjustment, tighten the anchor screws.
4, the import and export value of the chemical pump pipeline should have a support frame, can not use the chemical pump to support the point of support. The specifications for import and export trade pipes shall be the same as those for import and export trade of chemical pumps.
5. When the natural suction chemical pump is installed, the inlet pipe should be connected first, and then the outlet value pipe should be connected after the liquid is filled, and the effect of the brake is positive. The inlet pipeline of the pump must be paired with the pump, and the full length can not exceed 5 meters, otherwise it will harm the natural suction of the chemical pump natural suction effect, natural suction height width ratio can be calculated according to the formula: cold water natural suction 3m/ medium relative density = actually natural suction height width ratio.
6. After the installation of the chemical pump, finally rotate the shaft connecting device by hand to check whether there is a scratch problem. When rotating, it is easy and symmetrical that the installation is completed.
7, magnetic link chemical pump can not be extracted with particulate matter and very easy to crystal liquid, do not allow continuous operation under the condition of turning off the sewage outlet, need to maintain at least the total flow.
8, in order to avoid dirt into the chemical pump, at the entrance should be installed on the filter device, the total area of worry must be more than 3 ~ 4 times of the pipeline section.
9. The chemical pump with high pump head must also install the check valve on the export value pipeline to prevent the water hammer from suddenly shutting down.
10. It is necessary to ensure that the installation of the height to width ratio of the chemical pump is in line with the cavitation allowance of the pump, and it is also necessary to fully consider the pipeline damage and medium temperature. In order to avoid the cavitation allowance caused by the chemical pump body, it must be in accordance with the following relationship: NPSHaNPSHr 0.5NPSHa: Allowable Cavitation allowance (m)NPSHr Indispensable Cavitation allowance (m)NPSHa=106(PA-PV)/g no s-hf Pa: Effect on the surface of the conveyor medium working pressure (MPa)Pv: medium vapor working pressure (MPa) : the relative density of the medium (kg/m3)hs: suction width ratio (m)hf: suction pipe friction resistance (m) g: the additive force (m/s).
11, when the liquid temperature is high, it is necessary to adopt the water-cooling strategy for the seal of the chemical pump to avoid the rupture of the static ring of the mechanical seal deformation.
12. When the viscosity of the liquid extracted by the chemical pump is too high, the characteristics of the centrifugal pump and the output power are greatly changed.
Notes for use:
1. When installing chemical pump, pipeline weight can not be added to the pump. Should have their own supporting body, so as not to make deformation affect the operating performance and life.
2, stainless steel chemical pipeline pump and motor are integral structure, installation without alignment, so installation is very convenient.
3. The anchor bolt must be tightened during installation to avoid the impact of vibration on the performance of the chemical pump when starting.
4, before the installation of the chemical pump should carefully check whether there is no hard objects in the pump runner that affect the operation of the pump (such as stones, iron particles, etc.), so as to avoid damage to the impeller and pump body when the centrifugal chemical pump runs.
5, in order to convenient maintenance and use safety, in the chemical pump inlet and outlet pipeline installed a regulating valve and a pressure gauge near the pump outlet, to ensure that in the rated head and flow range of operation, to ensure the normal operation of the pump, increase the service life of the chemical pump.
6, pump used for suction occasions, should be equipped with the bottom valve, unless it is the self-priming pump can not install the bottom valve, and the inlet pipeline should not have too many bends, at the same time should not have water leakage, leakage phenomenon.
7. The discharge line, such as the check valve, should be installed outside the gate valve.
8. After installation, move the pump shaft, the impeller should have friction sound or stuck phenomenon, otherwise the pump should be disassembled to check the cause.
9, chemical pump installation is divided into rigid connection and flexible connection installation.
Chemical pump valve installation and use of key points
Chemical pump is used very frequently in chemical manufacturers for liquid delivery, and it is also common to use pipeline valves. There are many types and shapes of valves. What should we pay attention to in the installation and use process and how to install it?
One, the first is the direction and position, many valves have direction: such as globe valve, throttle valve, pressure reducing valve, check valve, etc., if inverted inverted, it will affect the use effect and life (such as throttle valve), or do not work (such as pressure reducing valve), and even cause danger (such as check valve). General valves have directional markings on the body. If not, it should be correctly identified according to the working principle of the valve. The valve chamber of the globe valve is not symmetrical, the fluid should be let from the bottom to the top through the valve port, so that the fluid resistance is small (determined by the shape), the opening of the force saving (due to the medium pressure up), the closed medium does not pressure packing, easy maintenance, this is why the globe valve can not be inverted. Other valves also have their own characteristics.
Do not flip gate (i.e. hand wheel down), otherwise the medium will remain in the valve cover space for a long time, easy to corrosion stem, and for some process requirements contraindo. It is very inconvenient to change the packing at the same time. Open stem gate valve, do not install underground, otherwise due to damp corrosion exposed stem. Lift check valve, installation to ensure that the disc vertical, so that flexible lifting. Swing check valves, when installed to ensure that the pin level, so that flexible swing. The pressure relief valve should be installed upright on the horizontal pipe, and do not tilt in any direction.
Two, the valve installation position must be convenient for operation; Even if the installation is difficult temporarily, think about the long-term work. The handwheel of the valve is in line with the chest (generally 1.2 meters away from the operating floor), so that it is easier to open and close the valve. Landing valve handwheel should be upward, do not tilt, so as to avoid awkward operation. The wall machine depends on the valve of the equipment, but also leave room for the operator to stand. To avoid the operation of the sky, especially acid and base, toxic media, otherwise it is not safe.

Three, valve installation steps: do not impact the valve made of brittle materials.
1, before installation, carefully check whether the model and specification of all valves are in line with each other, whether the packing is intact, whether the gland bolt has enough adjustment allowance, and check whether the stem and disc are talking, whether there is stuck and skewed phenomenon.
2. When lifting the valve, the rope should not be tied to the handwheel or valve stem to avoid damage to these parts, but should be tied to the flange; For the valves connected to the pipeline, be sure to clean.
3. When installing the screw valve, the sealing packing (twine and aluminum oil or polytetrafluoroethylene raw material belt) should be wrapped on the pipe thread, not to get into the valve, so as not to valve memory volume, affecting the flow of media. When installing flange valves, be careful to tighten the bolts symmetrically and evenly. Valve flange and pipe flange must be parallel, reasonable clearance, so as to avoid excessive pressure and even cracking of the valve. Especially for brittle materials and valves with low strength. Valves to be welded with pipes should be spot-welded first, then fully open the closing parts, and then welded dead.
4, some valves, in addition to the necessary protection facilities, but also have bypass and instrument. A bypass was installed. Easy to repair trap. Other valves, also have the installation of bypass. Whether to install the bypass depends on the valve condition, importance and production requirements.

Four, inventory valve, some packing is not good, and some do not conform to the use of the medium, which needs to change the packing; But when used, the filler must be adapted to the medium. When replacing the filler, press in round by round. Each ring seam to 45 degrees is appropriate, ring and ring open 180 degrees. The packing height should consider the room for continued pressing of the gland. At present, the lower part of the gland should be allowed to press the packing chamber to an appropriate depth, which can be generally 10-20% of the total depth of the packing chamber. For high demand valves, the joint Angle is 30 degrees. The seams between the rings are staggered by 120 degrees.
In addition to the above filler, rubber O-ring can also be used according to the specific situation (natural rubber resistance to weak alkali below 60 degrees Celsius, butadiene rubber resistance to oil crystals below 80 degrees Celsius, Fluorine rubber resistance below 150 degrees Celsius a variety of corrosive media) three pieces stacked polytetrafluoroethylene ring (resistance below 200 degrees Celsius strong corrosive media) nylon bowl ring (resistance below 120 degrees Celsius ammonia, alkali) forming filler. A layer of polytetrafluoroethylene (PTFE) raw material tape is wrapped around the common asbestos disc, which can improve the sealing effect and reduce the electrochemical corrosion of the valve stem. When pressing the seasoning, the valve stem should be rotated at the same time to keep it uniform around and prevent it from being too dead. The gland should be tightened evenly and not tilted.

Five, some valves must also have external protection, which is insulation and cooling. Hot steam lines are sometimes added to the insulation layer. What kind of valve should be insulated or kept cold, according to the production requirements. Where the medium in the valve reduces the temperature too much, will affect the production efficiency or freeze the valve, you need to keep heat, or even mix heat; Where the valve is exposed, adverse to production or cause frost and other adverse phenomena, it is necessary to keep cold. Insulation materials are asbestos, slag wool, glass wool, perlite, diatomite, vermiculite and so on; Cooling materials are cork, perlite, foam, plastic and so on