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Posted: 07/19/2017 08:48:03 Hits: 6
Through analyses of hazard sources in major processes, it can be determined which valves are the main valves and play the role of safety protection. The failure of these valves can lead to significant operation and safety accidents. Thus, it is of great importance to ensure the reliable, effici...
Posted: 07/05/2017 09:33:59 Hits: 13
The valve operating temperature is one of the problems which must be considered when valves are designed and selected. In order to standardize the appropriate operating temperature of valves' main materials and facilitate the valves' design, production, manufactu...
Posted: 06/16/2017 11:33:18 Hits: 20
In engineering, the common low temperature medium environments can be classified into 3 categories:
1. -50℃-0℃, the main material of the valve is low temperature carbon steel.
2. -70℃--51℃, the main material of the valve is austenitic stainless steel or nickel-based low-temperature steel.
Posted: 06/03/2017 14:14:35 Hits: 9
The balls of the trunnion mounted ball valve are fixed and will not move after the pressure. Therefore, the two seal rings should be designed to have sufficient pretightening force to ensure that the seal is a double-sided forced seal. Usually, the upper and l...
Posted: 05/23/2017 10:44:18 Hits: 14
Swing check valves have built-in rocker swing structure. All the valves' discs are installed in the valve bodies and can not pierce them. Except that the gaskets and sealing rings are used in the flange part, there is no leakage point o...
Posted: 05/05/2017 16:01:24 Hits: 41
The hard seal of the ball valve is the metal-to-metal seal and the valve body and seat are all made from metal. The precision of manufacturing and the processes are very difficult. Generally, the hard sealed ball valves are used for those working under high pressure which is usually gr...
Posted: 04/25/2017 12:02:26 Hits: 20
Slags and rust in the pipes blocking or stucking throttles, guidance parts, lower valve cover balance holes can cause drag marks and scratches on curved and guide surfaces of the spools and dents on the sealing surfaces. This often occurs in the new commissioning and initial operatio...
Posted: 04/22/2017 10:57:51 Hits: 16
L40800 adopts the design of maze type valve cage joint pressure balanced type valve spool and consists of a plurality of circular disk (layer) with coaxial surfaces distributed with labyrinths. According to the different process parameters of the medium, we design a number o...
Posted: 04/05/2017 13:39:49 Hits: 18
Forged steel gate valve is widely used in pipelines, which connects and cuts off the medium. It is not good for regulating the flow of the medium, but we can know the flow rate according to the height of its stem(for example, RVHX is used for firefighting and has a scale for opening and closing). Co...
Posted: 03/22/2017 09:20:39 Hits: 22
In the 1930s, the United States invented the butterfly valve and introduced it into Japan in the 1950s, it was widely used in Japan till 1960s. But butterfly valve was popularized in china after the 1970s. At present, butterfly valves whose size are over 300mm have gradually replaced the gate valve ...
Posted: 03/01/2017 16:36:56 Hits: 34
1. Nominal pressure
(1) Nominal pressure-the compressive strength of the product at the reference temperature.
(2) Reference temperature: different materials have different reference temperatures. For example, the reference temperature of steel is 250 °C.
(3) Nominal pressure 1.0Mpa, recorded as...
Posted: 03/01/2017 16:29:09 Hits: 9
Chlorine-specific valves are designed for chlorine(dry chlorine) and all types of high-risk medium. Besides its packing, it has bellows seal. Which has a double seal structure and can effectively prevent dangerous medium from leaking. Valve and valve seat adopt polytetrafluoroethylene and stellite h...
Posted: 02/20/2017 13:11:06 Hits: 17
At present, metal materials are widely used in the manufacturing of valves. The using of metal valves has a history of hundreds years, it has been through the improvement of structure and material, but still has its own limitation, that is, it can't meet the requirement of strong wear and corros...
Posted: 02/15/2017 13:19:26 Hits: 14
Nowadays, almost all of valves have the flaw of poor sealing performance. Many buyers, or even manufacturers don't know how to deal with it. After putting a lot of effort on the research, we have come up with four ways to solve the problem.
Carefully grind, remove mark, reduce or ge...
Posted: 01/25/2017 10:04:10 Hits: 26
To solve the problem of valve water and steam leakage, we need to know why it happens. We need to make sure to seal the valve well, so that it can maintain air tightness. If something goes wrong with sealing, there will be a leakage.
As a control part in the system of fluid delivery, valve ha...
Posted: 01/11/2017 10:36:24 Hits: 43
Domestic valve materials frequently-used technical standard, ductile iron specification and mechanical property
Posted: 08/17/2016 15:46:34 Hits: 92
In petroleum, chemical engineering, pharmacy, fertilizer, power and other industries, chlorine is usually used as oxidizing agent for its excellent oxidability. Meanwhile, chlorine is also rejected for its hypertoxicity. So, for the valves used for chlorine, what kinds of valves should be chosen by ...
Posted: 07/22/2016 17:25:12 Hits: 74
At present, as a kind of component to cut off or control flow rate in pipeline system, stainless steel butterfly valve has been widely applied in petroleum, chemical industry, metallurgy and power. For current well-known butterfly valve technology, sealing type of stainless steel butterfly valve ado...
Posted: 07/18/2016 13:57:50 Hits: 122
Structure of safety valves mainly has two types: spring type and lever type. Spring type safety valves refer to that the sealing between disc and seat is depending on force of spring. Lever type safety valves depend on applied force of lever and heavy hammer. For the demands for large capacity, puls...
Posted: 06/21/2016 11:43:36 Hits: 65
Sealing face on valve is used to cut off, connect, regulate, distribute, separate and blend media. So, sealing face is usually corroded, eroded and wore by media and is damaged easily.
Reasons damaging sealing face of valve is divided into artificial damage and natural damage. Artificial dama...
Posted: 04/22/2016 17:44:21 Hits: 80
Metal sealing trunnion ball valve is the new generation of high performance ball valve, appropriate for long distance pipeline and common industrial pipeline. The strength, security and resistance to bad environment of ball valve are fully considered during design. Metal sealing trunnion ball valv...
Posted: 04/11/2016 17:17:15 Hits: 107
The practice that definite specification, categories and working pressure meeting the requirements is imperfect in the current environment of market economy. For competition, valve manufacturers innovate respectively, forming their own enterprise standards and product features, under the conceptio...
Posted: 03/11/2016 16:30:00 Hits: 128
Titanium has already applied in chemical engineering, health care, salt manufacturing, chlor-alkali, aviation and other industries, for its good mechanical property and excellent corrosion resistance. In chemical engineering, titanium is mainly used for pressure vessel, pipelines and pump valve. A...
Posted: 03/07/2016 16:56:17 Hits: 125
The followings are the materials used for liner of valves for corrosion resistance.
1. PTFE (F4)
Applicable media: strong acid, strong base, strong oxidant, etc;
Operating temperature: -200～180℃;
Features: having excellent chemical stability, high heat resistance and low...
Posted: 12/28/2015 14:45:39 Hits: 173
Metal valves have been widely used in many industries for hundreds of years. Thought their structure and material have been improved, they can not meet the increasingly harsh working conditions because of the material restrictions. However, on the other hand, using ceramic materials in industrial ...
Posted: 12/02/2015 16:18:09 Hits: 246
Some Notes of Packing:
1. Packing filler should be cut with a 45-degree incision and each incision shifted 180 degrees when installation.
2. When using V-shaped PTFE packing in high pressure, you need to pay attention to the occurrence of cold flow.
3. Use molding flexible graphite packing ri...
Posted: 11/09/2015 15:57:54 Hits: 949
Basket strainer is consisted of filter basket, flange, flange covers, fasteners and other components. When the liquid enters the filter basket, solid impurity particles will be blocked in the filter basket, only clean fluid discharged from the filter outlet. And for cleaning, just unscrew th...
Posted: 10/23/2015 08:12:51 Hits: 620
a. Select valve wrench, screwdriver, pry bar, machining bars and other tools according to its required specifications.
b. Prepare an appropriate amount of cotton yarn, detergent and valve seal pad, fillers, lubricants, etc.
a. Operate the gate valve t...
Posted: 10/07/2015 17:19:48 Hits: 635
At present, with hundred years of development, metal valves have been widely used in China's industry. Limited by the conditions of metal material itself, though there had structure and material improvements, metal valves are increasingly unable to meet the high wear, strong corrosion and othe...
Posted: 09/19/2015 17:05:47 Hits: 829
Because of the different positions of stem thread, stem of globe valve can be divided into upper threaded stem and lower threaded stem.
Upper Threaded Stem
Transmission thread is located on the upper part of the stem, outside the cover and stuffing box. Without contacting the media, i...
Posted: 09/11/2015 16:15:27 Hits: 524
Installation for Low Temperature Gate Valve
1. Check the cavity, sealing surface and other parts before installation, no dirt or sand attached;
2. Bolts for every joint are required to be evenly tightened;
3. Packing site need to be compressed to ensure the seal performance of the packing an...
Posted: 09/04/2015 18:01:36 Hits: 407
According to different drive mode, actuator can be divided into there types: pneumatic actuator, hydraulic actuator and electric actuator. These three kinds of valve actuators have their own different characteristics. And the following is the simple comparison.
Posted: 08/19/2015 18:24:08 Hits: 680
Flow characteristics of control valve refers to the relationship between valve opening size and relative flow of medium under the conditions that a valve maintains constant differential pressure. There are three flow characteristics of control valve: parabolic characteristic, linear chara...
Posted: 08/12/2015 16:58:52 Hits: 362
Two-piece structure is the earliest infrastructure of ceramic valves. During the use, however, we found that this structure is not reasonable, so later we developed three-piece structure and it is often used on double seat valves. Now, we have a brief knowledge about the main structure of the cera...
Posted: 08/07/2015 08:14:46 Hits: 365
When rubber seal butterfly valves are used to throttle the flow, improper measures will produce cavitation and make the rubber seat flake or damaged. To this end, metal sealing butterfly valves with smaller cavitation areas have been produced in the international community. In recent years, China ...
Posted: 07/25/2015 16:04:22 Hits: 567
First, from the perspective of structure cost, solenoid valves have simple composition structure with an electromagnetic coil as the main component. And for their performance, solenoid valves can only play the switch function. Although the use of electric valves is very similar with solenoid valve...
Posted: 07/15/2015 16:33:55 Hits: 602
Application of oilfield valves
Oilfield valves are widely used in chemical, petroleum, natural gas, power plants, coal mines, construction, steel, light industry, sewage treatment and other industries. Because there are often hard particles, fibrous dirt and other objects in the media, so oilfie...
Posted: 07/10/2015 15:57:50 Hits: 566
With high performance, wide scope, good security and other advantages, API safety valves have widely used in different industries. However, during the long-term using process, safety valves are inevitable to meet all kind of problems. And the following is the introduction about how to deal with th...
Posted: 06/29/2015 14:58:44 Hits: 717
With the functions of diversion, cut-off, throttling, non-return and split-flow, valves, which are used to change the channel section and flow direction of medium, can control the pipelines in the fluid delivery system. From the simplest ones to the most complex automatic control valves, valves wi...
Posted: 06/23/2015 16:05:47 Hits: 555
As a modern classic work for butterfly valves, sanitary butterfly valve has become very popular among industries. So what are sanitary butterfly valves, and the characteristics?
With high-precision CNC lathes, the interchangeability of sanitary butterfly valves can be guaranteed, elimin...
Posted: 06/15/2015 10:23:45 Hits: 479
If you want to the Y-strainers have stable performance and long service life, you need to pay special attention to these following aspects:
1. Although the Y-strainers are closed, there are still media and pressure in the body. Before overhauling ball valves, you should first close the ...
Posted: 06/08/2015 15:43:57 Hits: 513
Ventilation butterfly valve is divided into manual transmission and electric transmission and its driving actuator can be drove by motor or turbine so that the disc can rotate freely within the range of 90 ° to achieve the opening and closing movement or regulating the flow of media.
Posted: 10/28/2014 16:55:36 Hits: 619
Hydraulic control valve should be installed the filter and also should convenient for the requirements of pollution discharge.
Hydraulic control valve is a kind of valve body that wet itself by water instead of being lubricated by adding engine oil. If the main parts within the king val...
Posted: 06/01/2015 11:01:04 Hits: 644
Eccentric semi-ball valve and flange valve belong to the same type of valve, but the difference is that the closure member of eccentric semi-ball valve is a sphere and this sphere can rotate around the center line of the body to achieve the open and close movement. Ball valves are mainly used for ...
Posted: 10/13/2014 16:10:07 Hits: 796
Two major points analyzing electric control butterfly valve installation:
1. Installation location, altitude and direction of import and export must comply with the design requirements. Pay attention to the medium flow direction which should be consistent with the body the direction of t...
Posted: 05/26/2015 09:05:31 Hits: 409
For pneumatic control valves, gas pressure relief valve is a necessary accessory which used mainly to reduce the pressure of air to a stable value, so that the control valve can obtain stable gas power for regulation. However, if the output pressure exceeds the limited pressure, the pipeline will ...
Posted: 09/22/2014 17:01:57 Hits: 648
Due to the wide application of electric butterfly valve, the service time inevitably influences its quality. However, is there a good way to maintain and protect them? Today, here we introduce about the relevant maintenance methods of electric butterfly valve.
1. Electric butterfly valve...
Posted: 01/08/2015 17:34:20 Hits: 715
For valve market distribution, the biggest user of valves is petrochemical industry, electric power department, metallurgy department, chemical industry and urban construction department mainly on the basis of the construction of the project.
It is analyzed that the main trend of valve ...
Posted: 08/28/2014 10:11:29 Hits: 624
Today's continuous progress in society economy and technology and constantly improvement of people's living standard promote the constantly upgrade of production technology. Thus, industrial production demand for various valve products is increasingly growing, for example, the sales of com...
Posted: 05/19/2015 16:38:55 Hits: 412
In the process of using a high vacuum butterfly valve, it will be often affected by temperature. And the following is the simple analysis:
1. Influenced by high temperature
After the relaxation of flange, bolts and gasket, the prestress of the bolts and the carrying capacity of flange...