Common Valves in operation cleaning, lubrication, grease method Share What common valves are used on the heat network?

Common Valves in operation cleaning, lubrication, grease method Share What common valves are used on the heat network?

Valve trapezoidal thread, valve stem nut and support sliding parts, bearing parts, gear and worm gear, worm meshing parts and other parts with activity, all need good lubrication conditions, reduce friction between each other, avoid mutual wear. Some parts are specially equipped with oil cup or nozzle. If it is damaged or lost in operation, it should be repaired and equipped, and the oil road should be dredged. Valve grease, often overlooked the amount of grease. After grease refueling, the operator selects the valve and grease connection mode before grease operation.
Maintenance of valve in operation
The purpose of maintenance during valve operation is to ensure that the valve is in a state of perennial tidiness, good lubrication, complete valve parts and normal operation.
(1) Cleaning of the valve
Valve surface, stem and stem nut trapezoidal thread, stem nut and support sliding parts and gear, turbine and media residual stains and other dirt, the valve will produce wear and corrosion. Therefore, it is obviously very important to keep the outside and active parts of the valve clean and protect the integrity of the valve paint. Dust on the valve is suitable for brush brushing and compressed air purging; Trapezoidal thread and the dirt between the teeth are suitable for cleaning cloth; The oil and medium residue on the valve is suitable for steam purging, even with copper wire brush washing, until the processing surface, with the surface showing metallic luster, paint surface showing the color of the paint. There should be a person responsible for the trap, at least one inspection per shift, regularly open the flushing valve and the plug at the bottom of the trap for flushing, or regularly remove flushing, so as to avoid dirt clogging the valve.
(2) valve lubrication
Valve trapezoidal thread, valve stem nut and support sliding parts, bearing parts, gear and worm gear, worm meshing parts and other parts with activity, all need good lubrication conditions, reduce friction between each other, avoid mutual wear. Some parts are specially equipped with oil cup or nozzle. If it is damaged or lost in operation, it should be repaired and equipped, and the oil road should be dredged.
Lubrication parts should be refueled regularly according to the specific situation. Frequently opened, high temperature valve is suitable for a week to a month interval refueling once; Infrequently opened, low temperature valve refueling cycle can be longer. Lubricants include oil, butter, molybdenum disulfide and graphite. High temperature valves are not suitable for oil and butter, which will be lost due to high temperature melting, and suitable for injection of molybdenum disulfide and graphite powder lubrication. On the exposed parts that need lubrication, such as trapezoidal thread, gear and other parts, if the use of butter and grease, easy to dust, and the use of molybdenum disulfide and graphite powder lubrication, it is not easy to dust, lubrication effect is better than butter. Graphite powder is not easy to apply directly, can be used with a little oil or water synthesis paste. The plug valve of the oil seal should be oiled at the specified time, otherwise it is easy to wear and leak.
(3) Grease valve
When the valve grease, often ignore the problem of the amount of grease. After grease refueling, the operator selects the valve and grease connection mode before grease operation. There are two situations: on the one hand, the amount of grease is small and the amount of grease is insufficient, and the sealing surface is worn faster due to the lack of lubricant. On the other hand, excessive fat injection causes waste. The reason is that there is no accurate calculation of the valve seal capacity according to the valve type class. The sealing capacity can be calculated by valve size and category, and then a reasonable amount of grease can be injected.
Valve grease, often ignore the problem of pressure. During the grease operation, the grease pressure will change regularly from peak to valley. If the pressure is too low, the seal will leak or fail! The pressure is too high, the grease injection port is blocked, the seal grease is hardened or the seal ring is locked with the ball and the gate. Usually when the grease injection pressure is too low, the injected grease flows into the bottom of the net cavity, generally occurring in small gate valves. While the grease injection pressure is too high, on the one hand, check the grease nozzle, if the grease injection hole is blocked, replace it; On the other hand, lipid hardening, cleaning fluid should be used to repeatedly soften the failed seal grease, and inject new grease replacement. In addition, seal type and seal material, also affect the injection pressure, different seal forms have different injection pressure, in general, the hard seal injection pressure is higher than the soft seal.
③ When the valve grease, should pay attention to the valve in the switch position. Ball valve maintenance is generally in the open state, special circumstances choose to close the maintenance. Other valves should not be in the open state. The gate valve must be closed during maintenance to ensure that the grease is filled with sealing groove along the sealing ring. If it is in the open state, the sealing grease will directly fall into the flow channel or valve chamber, resulting in waste.
④ When valve grease injection, the effect of grease injection is often ignored. The pressure, amount of grease injection and switch position are normal in grease injection operation. However, IN ORDER TO ensure the grease effect of the valve, it is sometimes necessary to open or close the valve, check the lubrication effect, and make sure that the ball or gate surface lubrication is uniform.
⑤ When grease injection, we should pay attention to the valve body drainage and wire blocking pressure relief. After the valve pressure test, the gas and moisture in the valve chamber of the sealing chamber are boosted due to the rise of the ambient temperature, and the drainage and pressure relief should be carried out first when the grease is injected, so as to facilitate the smooth progress of the grease injection work. After grease injection, the air and moisture in the sealing chamber are fully displaced. Timely release the pressure of the valve chamber, but also to ensure the safety of the valve. After the grease injection, it is necessary to tighten the drain and pressure relief wire plug to prevent accidents.
⑥ When injecting fat, we should pay attention to the problem of uniform fat. In normal grease injection, the grease hole closest to the grease injection mouth is the first fat, and then to the low point, is the high point, successively out of the fat. If not according to the law or no fat, it is proved that there is blockage, should be timely clearance treatment.
⑦ grease, but also to observe the valve diameter and sealing ring seat flat problem. For example, ball valve, if there is open position interference, you can adjust the open position limiter inward, make sure the diameter is straight and then lock. Adjust the limit not only the pursuit of open or close party position, to consider the whole. If the opening position is flat and not in place, the valve will not be tightly closed. Similarly, when adjusting the closing position, we should also consider the corresponding adjustment of the opening position. Ensure right Angle stroke of valve.
⑧ fat injection, must be sealed fat injection mouth. Avoid impurities into, or grease injection mouth lipids oxidation, the cover should be coated with anti-rust grease, avoid rust, so that the next operation application.
⑨ When fat injection, we should also consider the specific treatment of specific problems in the sequential transportation of oil products in the future. In view of the different qualities of diesel and gasoline, the scouring and decomposition capacity of gasoline should be considered. In the future valve operation, when encountering gasoline section operation, timely supplement grease to prevent wear.
⑩ Grease injection, do not ignore the stem part of the grease. Valve shaft parts have sliding sleeve or packing, also need to maintain lubrication, in order to reduce the friction resistance during the operation, such as not to ensure lubrication, electric operation torque increase wear parts, manual operation switch effort
Some ball valves are marked with arrows on the body if the word “FLOW” is not included. Writing, it is the direction of the sealing seat, not as a reference medium flow direction, the valve self-leakage direction is opposite. Typically, double-seater sealed ball valves have bidirectional flow.
What common valves are used on the thermal network? The heat pipe network, also known as the heat pipe, starts from the boiler room, the direct gas turbine room, the heating center and so on, and leads from the heat source to the heat inlet of the building. Multiple heating pipelines form a network. The starting point of the main line, branch line and branch line of the heat network pipeline shall be installed with the shut-off valve. > Heat pipe network, also known as the heat pipe, starts from the boiler room, direct gas turbine room, heating center, etc., and leads from the heat source to the heat inlet of the building. Multiple heating pipelines form a network.
The starting point of the main line, branch line and branch line of the heat network pipeline should be installed with the shut-off valve.
The main line of hot water heating network shall be equipped with segmented valves. The spacing of the segmented valve should be: conveying trunk line, 2000 ~ 3000m; Transmission and distribution trunk line, 1000 ~ 1500m; Steam heating network can not be installed with segmented valves. Two-way sealing valves should be used for the segment valves of the connected trunk line and the ring pipe network between the heat sources of the multi-heat source heating system.
A bypass valve shall be installed on the gate valve of the pipeline whose working pressure is greater than or equal to 1.6MPa and nominal diameter is greater than or equal to 500mm. The diameter of the bypass valve can be selected by one tenth of the diameter of the valve.
When the water filling capacity of the heating system is limited and the water filling flow of the pipeline needs to be controlled or the steam volume needs to be controlled when the steam pipeline starts the warm pipe, the pipeline valve should be equipped with a bypass valve of smaller caliber as the control valve.
When the dynamic hydraulic analysis needs to prolong the closing time of the segment valves of the transmission line to reduce the pressure transient value, the method of parallel bypass valve of the main valve should be adopted to solve the problem. Bypass valve diameter can be a quarter of the diameter of the main valve. The main valve and bypass valve should be interlocking control, the bypass valve must be in the open state before the main valve can be closed, the bypass valve can be closed after the main valve is closed.
Valves with nominal diameter greater than or equal to 500mm should be electrically driven. For valves remotely operated by the monitoring system, the bypass valves shall also be electrically driven.
There are many types of valves used in a thermal network. Such as gate valve, globe valve, ball valve, butterfly valve, check valve, safety valve, regulating valve, balance valve, self-balancing valve and so on. Gate valve it plays a role in the pipeline shut off; Globe valve it plays a role in the pipeline shut off, can roughly adjust the flow; Ball valve, butterfly valve in the pipeline to shut off the role; Check valves are usually installed at the pump outlet to prevent water hammer damage to the pump. Regulating valve to adjust the flow distribution between the pipeline medium to achieve thermal balance; Safety valves are widely used in pressure vessels.