Blog

15

2019

/

10

Common leakage problems and solutions in the use of gate valves

Gate valve is mainly divided into: manual gate valve, pneumatic gate valve, stainless steel gate valve, forged steel gate valve, American standard gate valve, electric gate valve, gas gate valve, knife gate valve, dark rod gate valve, bright rod gate valve, bellows gate valve and so on. Gate valve as all the switch valve, the development of universal application of the petroleum, chemical, electric power, water conservancy and other industries, is one of the most widely used valves. Therefore, the problems and solutions in the use of gate valves are particularly important. One: the simplest treatment, check whether the gate valve and the gate valve coupling bolt is tightened, if not tightened, the gasket ring and flange sealing groove surface is not fully combined often lead to leakage. The bolts and nuts shall be checked in sequence, and all bolts shall be tightened until the gasket ring is pressed tightly. Secondly, check the size and accuracy of the sealing gasket ring and flange sealing groove surface. If the size of the sealing contact surface is incorrect or too rough, repair or update the sealing gasket ring. Two: the valve cover leakage, is the part of the valve cover and the body bolt connection, mainly in the packing seal leakage. First check whether the seal is selected correctly and whether it matches the sealing groove. If there is such a problem, replace the sealing ring or repair the sealing groove. Secondly, check whether the seal has burrs, fracturing, twisting and other phenomena. In this case, replace the seal. Again, check whether the sealing surface of each sealing groove is rough or has other defects. If there are defects, eliminate the defects or update the damaged parts. Three: valve leakage, in addition to man-made factors, the valve body in the casting process, sometimes there will be sand holes, sand holes and other casting defects, in the machining process is difficult to be found, once the pressure is applied, hidden casting defects will be exposed. In this case, the valve body shall be repaired, repaired or renewed. Four: valve seat and valve plate between the leakage, this is what we usually call the sealing surface leakage or seal leakage, the leakage of the reason is relatively complex. Generally, it can be divided into two categories: one is the leakage of the sealing surface, and the other is the leakage of the root of the sealing ring. First check the valve seat and valve plate contact sealing surface accuracy, the sealing surface at least to grinding, such as the surface accuracy is too rough, it should be removed to re-grinding. Secondly, check the sealing surface for defects such as pitting, indentation, sand holes, cracks, etc. In this case, replace the valve plate or valve seat. In addition to the defects caused by the processing and casting process of these products, there are also human factors: it is easy to enter the welding inspection, iron filings, impurities and other foreign matters during the installation process, and such sundries should be cleaned before installation. If you forget to clean or clean up is not complete, it will cause the valve plate to close less than the expected depth and produce leakage. In this case, remove the valve body and clean it again. Therefore, for the selection and use of gate valves, we must choose reliable and stable quality. Wuhan Xiete Valve Technology Co., Ltd. quality assurance, welcome new and old customers come to order.

27

2019

/

09

How to maintain the valve

Valve use maintenance 1, the purpose of the use of maintenance, is to extend the life of the valve and ensure reliable opening and closing. 2, stem thread, often with the stem nut friction, to apply a little yellow dry oil, molybdenum disulfide or graphite powder, lubrication. 3, not often open and close the valve, but also regularly turn the hand wheel, the stem thread to add lubricant. 4. The valve stem, especially the threaded part, should be wiped frequently, and the lubricant that has been soiled by dust should be replaced with a new one, because the dust contains hard debris, which is easy to wear the thread and the surface of the valve stem, affecting the service life. 5, to always check and maintain the integrity of the valve parts. 6, do not rely on the valve to support its

18

2019

/

09

Relationship between valve diameter and medium flow rate

Valve flow and flow rate mainly depends on the diameter of the valve, but also with the structure of the valve on the resistance of the medium, at the same time with the valve pressure, temperature and the concentration of the medium and other factors have a certain intrinsic link. The flow area of the valve is directly related to the flow rate and flow rate, and the flow rate and flow rate are two interdependent quantities. When the flow rate is constant, the flow rate is large, and the flow channel area can be smaller; the flow rate is small, and the flow channel area can be larger. On the contrary, the flow channel area is large, its flow rate is small; the flow channel area is small, its flow rate is large. The flow rate of the medium is large, the valve diameter can be smaller, but the resistance loss is large, and the valve is easily damaged. Large flow velocity, flammable

02

2019

/

09

How to choose the flow rate of electric regulating valve

The flow characteristics of the electric control valve are divided into ideal flow characteristics and working flow characteristics. In general, the flow characteristics we provide are ideal flow characteristics, while practical applications require working flow characteristics. Therefore, in the choice of control valve flow characteristics, should first consider the choice of working flow characteristics. Then, the ideal flow characteristics are selected according to the practical application. The ideal flow characteristics commonly used in production are linear, equal percentage and quick opening characteristics. The quick-opening characteristic is mainly used for two-position control and program control, so the choice of regulating valve flow characteristics usually refers to how to reasonably choose the linear and equal percentage ideal flow characteristics. In actual use, the total

22

2019

/

07

Application Conditions and Operation of Gate Valves

Gate valve refers to the valve that the closing member moves in the vertical direction along the center line of the passage. Gate valve in the pipeline can only be fully open and fully closed cut off, can not be used for adjustment and throttling. Gate valve is a valve with a wide range of use. Generally, cut-off devices with a diameter greater than 50mm are selected, and cut-off devices with a small diameter are sometimes selected. The gate has two sealing surfaces, the most commonly used mode gate valve two sealing surfaces to form a wedge, wedge angle varies with the valve parameters. The gate of the wedge gate valve can be made into a whole, called a rigid gate; it can also be made into a gate that can produce micro-deformation to improve its manufacturability. When the gate valve is closed, the sealing surface can only

16

2019

/

07

Service life of valve packing

In the valve design or use experience, lift valve packing for asbestos packing, graphite packing, polytetrafluoroethylene packing, but these kinds of packing are limited by the number of valve opening and closing, that is, with the increase of the number of valve opening and closing, the packing will wear, the gap gradually increases, to a certain number of valves will leak from the packing. After leakage, the packing gland needs to be repressed. This scheme is suitable for the number of valve opening and closing occasions. If the valve is opened and closed frequently, this will undoubtedly increase the use and maintenance costs of the valve. When the valve is opened and closed many times, it can still be sealed: 1. add a gasket under the packing, under the gasket

08

2019

/

07

Leakage of valve packing and its solution

Reasons for leakage of valve packing: 1. The packing is not selected correctly, is not resistant to corrosion of medium, and is not resistant to high pressure or vacuum, high temperature or low temperature of the valve; 2. The packing is not installed correctly, and there are defects such as poor spiral winding joint, tightening and loosening, replacing large with small. 3. The packing has aged and lost its elasticity after exceeding its service life. 4. The precision of the valve stem is not high, there are defects such as bending, corrosion, wear, etc.; 5. The number of packing circles is insufficient, and the gland is not compressed; 6. The gland, bolts, and other parts are damaged, so that the gland cannot be compressed; 7. Improper operation, excessive force, etc.; 8. The gland is skewed, and the gap between the gland and the valve stem is too small or too large, causing the valve stem to wear

01

2019

/

07

Selection of electric stop valve

When the electric cut-off valve is in the open state, there is no contact between its valve seat and valve sealing surface, so its sealing surface mechanical wear is small. In the process of opening and closing, the friction between the valve flap and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant. Open height is generally only 1/4 of the diameter of the seat channel, so much smaller than the gate valve. Usually there is only one sealing surface on the valve body and the valve clack, so the manufacturing process is better and easy to repair. The flow direction of the medium through such valves has changed, so the flow resistance of the electric stop valve is higher than other valves. Electric cut-off valve selection: electric cut-off valve often

< 1...394041...65 >
WeChat Public Number
Mobile phone official website
WeChat Public Number

Cookie

Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy

Cookie

Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy

These cookies are necessary for basic functions such as payment. Standard cookies cannot be turned off and do not store any of your information.

These cookies collect information, such as how many people are using our site or which pages are popular, to help us improve the customer experience. Turning these cookies off will mean we can't collect information to improve your experience.

These cookies enable the website to provide enhanced functionality and personalization. They may be set by us or by third-party providers whose services we have added to our pages. If you do not allow these cookies, some or all of these services may not function properly.

These cookies help us understand what you are interested in so that we can show you relevant advertising on other websites. Turning these cookies off will mean we are unable to show you any personalized advertising.

Contact Information

+86 27-8970 8339

Tel: +86 27-8970 8619

WhatsApp: +86 181 7126 2929

E-mail: whylgd@vip.163.com

Address: No.5, Zhengjie, Shuangliu Street, Xinzhou District, Wuhan City, Hubei Province