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Posted: 10/27/2017 13:10:29 Hits: 8
7. Adopting electrochemical protection
There are two kinds of lectrochemical protection, anode protection and cathodic protection.
If zinc is used to protect iron and it is corroded, zinc is called the sacrificial metal. In the production practice, the anode protection is used less than the cathodi...
Posted: 10/23/2017 15:08:45 Hits: 3
5. Spraying paint
Paint is most widely used for the corrosion resistant of valves, which is an indispensable anti-corrosion materials for valve products.
Paint belongs to the non-metallic material, which is usually made from synthetic resin, rubber slurry, vegetable oil, solvent, etc., covering the...
Posted: 10/17/2017 15:15:17 Hits: 8
3. Adopting the surface treatment for metals
Joints of valves
Galvanization, chromeplate and oxidation treatments can be adopted for bolts of valves so as to improve the bolts' resistance to air and corrosive media. Besides the above mentioned three methods, the phosphorization surface treatmen...
Posted: 10/14/2017 10:24:24 Hits: 10
1. Selecting corrosion resistant materials according to corrosive media
In the production practice, the corrosion of the medium is very complicated. Even if valves made of the same material have the same media, the conditions of each valve being corroded by media vary from each other due to the dif...
Posted: 09/27/2017 11:57:40 Hits: 4
Except the throttle valve, all the valves are supposed to have certain closing sealing performance, so the valves must go through the sealing test before they leave the factories. The valves with the back seats also need to undergo the back seat sealing test.
The sealing test for the val...
Posted: 09/05/2017 17:03:47 Hits: 5
5. Using the ordinary flange for the butterfly valve. The flange used for the butterfly valve is different from the ordinary flange in the size. Some ordinary flanges have small diameters, while the butterfly valves may have large valve clacks, which will cause the butterfly valves can not be opened...
Posted: 08/25/2017 11:41:53 Hits: 14
A valve is a device which we use to control the direction, pressure and flow of a fluid in a fluid system, which can make the media such as the liquid, the gas and the powder in the pipe or equipment flow or cut off. In the construction process, the installation of the valve will...
Posted: 08/04/2017 14:36:02 Hits: 13
Evaluate the regional fire risk per the following factors: the flammability, physical and chemical properties of materials, the release frequency and quantity of combustible substances, the characteristics and arrangement of equipment and pipelines, the terrain, climate and ventilation conditio...
Posted: 07/19/2017 08:48:03 Hits: 18
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: 21
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: 25
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: 12
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: 16
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: 52
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: 28
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: 20
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: 20
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: 26
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: 89
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: 11
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: 19
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: 18
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: 32
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: 44
Domestic valve materials frequently-used technical standard, ductile iron specification and mechanical property
Posted: 08/17/2016 15:46:34 Hits: 97
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: 81
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: 141
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: 79
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: 87
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: 118
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: 132
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: 129
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: 250
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: 643
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: 644
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: 834
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: 526
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: 696
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: 363
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: 366
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: 579
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: 605
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: 578
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: 728
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: 561
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: 514
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.