Low temperature valve manufacturing and installation requirements, really pay attention to! German KNF diaphragm pump troubleshooting

Low temperature valve manufacturing and installation requirements, really pay attention to! German KNF diaphragm pump troubleshooting

Installation requirements for low temperature valves
Because of the special structure of the low temperature valve, the installation of the low temperature valve also has its special requirements. Because OF THE LONG NECK COVER STRUCTURE OF THE CRYOGENIC VALVE, THE STEM DIRECTION OF THE CRYOGENIC VALVE MUST BE WITHIN 45 DEGREES OF THE VERTICAL DIRECTION, AND SHOULD BE AVOIDED IN THE VERTICAL LINE AS FAR AS POSSIBLE. Otherwise the low temperature medium will fill the extended part of the valve cover, causing the failure of the valve packing, and will transfer the cold capacity to the valve handle, bringing personal injury to the operator. For the low-temperature valve with pressure relief structure, special attention should be paid to the valve pressure relief direction when installing the valve. The DIRECTION OF valve pressure relief should be marked on the process flow chart, and reflected in the pipeline axometric drawing (this is extremely important, extremely important, extremely important), if it is necessary to set up pressure relief hole but not set up, after the valve is closed, the liquid in the valve chamber is heated gasification, easy to cause the valve body burst. When the pressure relief direction is wrong, the combustible or toxic process medium may be discharged to the operation and maintenance side, resulting in casualties!
Low temperature valve manufacturing
The production of low temperature valve has developed a strict manufacturing process and the use of advanced equipment, the parts of the processing of strict quality control. After special low temperature treatment, rough-machined parts are placed in the cooling medium for several hours (2-6 hours) to release the stress, ensure the low temperature performance of the material, ensure the finishing size, to prevent the leakage caused by the deformation of the valve due to the temperature change in the low temperature working condition. Valve assembly and ordinary valves are also different, parts need to be strictly cleaned to remove any oil, to ensure performance.
Low temperature valve inspection
In addition to normal temperature and low temperature test, low temperature valve should also be tested as follows
1, the main parts of the warm valve should be cryogenic treatment (how cryogenic treatment later we have a chance to talk about, the following figure is the cryogenic treatment of the valve).
2. The main parts and welds should be subjected to low temperature impact test to ensure that the valve is not brittle at low temperature;
3, the valve must be tested at room temperature, first 1.5 times the nominal pressure water pressure strength test, and then 1.1 times the nominal pressure seal test;
4, after the hydraulic test valve must be moisture, no grease, and keep dry;
5, each batch of low temperature valves should be sampled according to a certain proportion of low temperature test, low temperature test must be conducted after 1.5 times of water pressure strength test;
6. After the low temperature test of the valve, air should be prevented from entering the valve;
7. After the low temperature test of the valve, it should be heated naturally or blown by a fan. It is forbidden to accelerate the temperature of the valve by heating and other methods.
8. Tighten the valve fasteners again after the natural temperature rise of the valve in low temperature test;
9. When the valve is put into storage, it is necessary to check the valve switch to ensure that the valve is in a reasonable state;
10, the valve storage and transportation process, should pay attention to the stainless steel and carbon steel valves separate, and do a good job of dust, waterproof, oil and collision prevention;
11. The flow direction, pressure relief direction and nameplate of the valve shall be checked in accordance with the requirements of the design unit.
German KNF diaphragm pump troubleshooting
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Germany KNF diaphragm pump principle
An elastic diaphragm mounted on an eccentric crankshaft is driven up and down by a motor. The cavity is deformed to realize the pumping and discharging of the medium. The pump is completely oil free in the process of transferring, evacuating and compressing the medium.
KNF diaphragm pump features
1, the medium is not polluted
2, can be made into full teflon, strong acid and alkali resistance
3, small size, compact design, almost does not occupy the laboratory space
4. It can work continuously for 24 hours, and will not stop the experiment because of overheating of the pump
5, as quiet as household appliances, micro vibration
6, installation environmental protection, maintenance free
KNF diaphragm pumps are broadly divided into KNF OEM (i.e. diaphragm pumps installed in equipment), KNF PROCESS (industrial flow pumps) and KNF LAB (laboratory portable diaphragm pumps).
Troubleshooting of KNF diaphragm pump
KNF diaphragm pump work troubleshooting guide when encountered in one or more of the following situations, this information can be used as a guide to help you develop maintenance measures.
The following are some of the abnormal operation conditions described in this guide: A) fast cycle/low flow B) no cycle/slow cycle/irregular cycle C) leakage D) noise E) component rupture
In the process of pump application, these situations are possible to encounter. Each condition can be divided into several possible causes. This guide lists the cause of the failure and gives the correct maintenance measures accordingly. The meanings of all specific terms in the guide are listed below.
Air VALVE – COPPER or stainless steel valve housing is secured to the pump central body by four bolts.
Piston – An aluminum cylinder enclosed in an air valve controls the flow of air.
Cavitation – Pump discharge below quota due to reduced or lack of inflow volume at the pump inlet. In fact, the chamber is provided with a full flow of fluid before discharge.
Static RELEASE HEAD – VERTICAL distance in feet from pump CENTER line to free TRANSFER POINT – INLET PRESSURE – INLET is measured in pounds and includes specific gravity and flow rate of fluid.
Specific gravity – the ratio of flow rate to water weight at 68F. The specific gravity of 68F water is 1.0
Static suction head – the vertical distance from the feed level to the center line of the pump. The pump should be above the liquid level.
Vapor pressure – The pressure produced by the vapor of all liquids on their free surfaces. In ANY PUMP OPERATING SYSTEM, THE OPERATING PRESSURE MUST not BE LOWER THAN THE STEAM PRESSURE, otherwise THE steam formed will partially or completely cut off the flow into the pump. Viscosity – Viscosity is the property of a fluid that causes resistance to flow due to friction within the fluid.
Water hammer action – Water hammer is in a sudden power failure or when the valve is closed too fast, because of the inertia of pressure water flow, produce water shock wave, just like a hammer, so called water hammer. The back-and-forth force of the water shock wave can be so strong that it can damage valves and pumps. The water hammer effect means that inside the pipe, the wall of the pipe is smooth and the water flows freely. When the open valve suddenly closes, the flow of water on the valve and pipe wall, mainly the valve will create a pressure. Because the pipe wall is smooth, the subsequent water flow quickly reaches the maximum under the action of inertia, and produces a destructive effect, which is the water hammer effect in hydrology, that is, the positive water hammer. This factor should be considered in the construction of water conservancy pipelines. On the contrary, the closed valve in the sudden open, will also produce water hammer, called negative water hammer, also has a certain destructive power, but not as big as the former.
Troubleshooting of KNF diaphragm pump
KNF diaphragm pump common fault causes and treatment methods:
1, diaphragm pump flow insufficient fault causes and treatment methods
a, inlet and discharge valve leakage; Repair or replace the feed valve
b. Diaphragm damage; To replace diaphragm
c, the speed is too slow, the adjustment failure; Maintenance control device, adjust speed.
2, diaphragm pump pressure is insufficient or elevated fault causes and treatment methods
a. Improper adjustment of pressure regulating valve of pneumatic diaphragm pump; Adjust the pressure valve to the required pressure;
b, pressure regulating valve failure; Maintenance pressure adjustment wide;
c, pressure gauge spirit; Repair or replace the pressure gauge.
3, diaphragm pump pressure drop fault causes and treatment methods
A. The oil filling valve is insufficient; Repair oil valve;
B. Insufficient feed or leakage of feed valve; Check feed condition and feed valve;
c, plunger seal oil leakage; Overhaul the sealing part;
d. The oil level of the storage tank is too low; Fill with new oil;
e. Pump body leakage or diaphragm damage; Check and replace the gasket or diaphragm.
4, diaphragm pump oil leakage fault causes and treatment methods
A. The sealing pad and the sealing ring are damaged or too loose; Adjust or replace the gasket and ring.
Common faults of KNF diaphragm pump
KNF diaphragm pump in operation should be no abnormal sound, no running, running, dripping, leakage phenomenon, pressure gauge, control valve work reliably, the performance indicators to meet the specification rated capacity or can meet the production requirements. But due to normal wear and tear or the aging of parts and components materials, failures can also occur.
KNF diaphragm pump pressure is insufficient or elevated fault causes and treatment methods: 1, pneumatic diaphragm pump pressure regulating valve improper adjustment; 2. The pressure regulating valve fails; Maintenance pressure adjustment wide 3 pressure gauge spirit; Repair or replace the pressure gauge
Diaphragm pump pressure drop fault causes and treatment methods: 1, fill oil valve fill oil is insufficient; 2. Insufficient feed or leakage of feed valve; 3. Oil leakage in plunger seal; 4. The oil level of the storage tank is too low; 5, pump body leakage or diaphragm damage; Check and replace the gasket or diaphragm.
KNF diaphragm pump flow shortage fault causes and treatment methods: 1, inlet and discharge valve drain; Repair or replace the feed valve 2, diaphragm damage; 3. The speed is too slow and the adjustment fails; Maintenance control device, adjust speed.
Diaphragm pump oil leakage causes and treatment methods: gasket, seal ring damage or too loose; Adjust or replace the gasket and ring. Pneumatic diaphragm pump has action, but the flow rate is small or no liquid outflow:
1. Check the cavitation phenomenon of the pneumatic diaphragm pump, reduce the speed of the pump to let the liquid into the liquid chamber.
2. Check whether the valve ball is stuck. If the operating liquid is not compatible with the pump elastomer, the elastic body will have a swelling phenomenon. Please replace the elastomer with the appropriate material.
3. Check whether the joint at the inlet of the pump is completely locked without leakage, especially the clamp near the valve ball at the inlet end.
Air valve of pneumatic diaphragm pump icing: check whether the water content of compressed air is too high, install air drying equipment
Air bubbles are produced at the outlet of the pump pneumatic diaphragm pump: check whether the diaphragm is broken, check whether the clamp is locked, especially the inlet pipe clamp.
Product from the air discharge outlet: check whether the diaphragm is broken, check whether the diaphragm and the inner and outer splint are clamped on the shaft
Valve rattle: Increase outlet or inlet head.
Pneumatic diaphragm pump disassembly and reassembly guide:
Warning: Before REPAIRING the pump, remove the air source piping from the pump and drain the air pressure in the pump. Remove all lines connecting the inlet and outlet of the pump and discharge the fluid from the pump into the appropriate container. Wear protective hat, glasses and gloves
Pump is inactive or operates very slowly:
1. Check whether there are impurities in the filter screen or air filter device at the air inlet.
2. Check whether the air valve is stuck and clean the air valve with cleaning liquid.
3. Check whether the air valve is worn out and replace it with a new part if necessary.
4. Check the condition of the sealing parts of the centrosome. If serious wear occurs, the sealing effect cannot be achieved, and the air will be discharged from the air outlet. Because of its special construction, use only GLYD circles.
5. Check whether the piston in the air valve works properly.
6. Check the type of lubricating oil. If the oil added is higher than the recommended oil viscosity, the piston may jam or not work properly. It is recommended to use a light and frost resistant lubricant.
The German KNF Group is a global leader in diaphragm pumps and corresponding systems as well as derivative industrial and laboratory products. As the highest quality diaphragm pump manufacturer made in Germany and spanning the whole field of industry and laboratory, we have been committed to providing customers around the world with the best gas and liquid media products and perfect global technical services. KNF’s industrial products have been used in medical devices, analytical instruments, chemical industry, process industry, biopharmaceutical, environmental protection, printing, metering, energy, food, aerospace, security and many other industries. And laboratory products in institutions of higher learning, research institutes, enterprises R & D testing center and other real