As a professional Valve manufacturer, Landee termly releases Technical Articles about industrial Valves, Valve industry, Valve technology.
Posted: 05/11/2020 12:53:07 Hits: 111
1. Gate valve:
A gate valve refers to a valve in which the closing member (gate) moves along the vertical direction of the channel axis. The gate valve is mainly used to cut off the medium on the pipeline, that is, fully open or fully closed. Generally, a gate valve cannot be used to regulate ...
Posted: 05/11/2020 12:43:55 Hits: 75
1. Globe valve:
A globe valve refers to a valve in which the closing member (valve flap) moves along the center line of the valve seat. According to the movement of the valve flap, the change of the valve seat port is directly proportional to the stroke of the valve flap. Because the opening o...
Posted: 07/26/2019 16:54:48 Hits: 233
Can we use a globe valve instead of a gate valve, or vice versa?
Let us introduce the difference between the globe valve and the gate valve.
When the installation space is limited, you should pay attention to the selection:
The gate valve can be tightly closed with the sealing su...
Posted: 11/02/2018 13:45:49 Hits: 230
volleyball regeln netz übergreifen
Evolving from plug valves, ball valves are a kind of quarter-turn valves whose disc is ball shape. They are mainly used for blocking off, distributing and changing the direction of flow, of which, ball valves with V-type opening have a better flow rate moderating function.
Posted: 11/01/2018 16:01:29 Hits: 280
It is a valve that vertically moves along the axis of tunnel, and is used for on/off control of the flow of medium rather than moderating flow rate. Gate valves are able to withstand high or low temperature or pressure and convey a wide range of media, but not including mud type media gen...
Posted: 09/26/2018 10:25:15 Hits: 79
The flow rate and flow velocity of a valve mainly depend on its diameter, as well as factors like the resistance of its structure against the medium. Meanwhile, they are also related to, but not limited to the valve's pressure, temperature, and the density of the medium.
Q (flow rate) = Av (ar...
Posted: 08/10/2018 14:26:49 Hits: 63
Valves used for adding reagent system in waterworks
The characteristics of the adding reagent system determine that the valve it used has a small diameter and a low flow rate, but high requirement of flow regulation, high accuracy requirement, and fast adjustment speed. Therefore, a flow control val...
Posted: 07/20/2018 10:47:38 Hits: 51
Valves used for filters
The most common filter is a four-valve filter, which is also the most basic configuration of the filter. No matter what kind of filter, there are at least four types of valves, including inlet valves, drain valves, flush valves and clean water valves. Of cours...
Posted: 06/02/2018 10:22:39 Hits: 46
The conventional water production process of waterworks start from obtaining raw water, getting the raw water, getting sediment in the sedimentation tank, filtering the water in the filter tank to the water coming from the pumping house in the end. Valves need...
Posted: 10/27/2017 13:10:29 Hits: 106
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: 26
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: 36
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: 51
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: 27
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: 20
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: 31
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: 25
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: 47
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: 45
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: 39
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: 20
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: 28
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: 96
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: 48
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: 60
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: 34
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: 62
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: 3313
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: 37
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: 32
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: 28
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: 46
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: 49
Domestic valve materials frequently-used technical standard, ductile iron specification and mechanical property
Posted: 08/17/2016 15:46:34 Hits: 111
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: 100
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: 302
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: 97
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: 96
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 valve ...
Posted: 04/11/2016 17:17:15 Hits: 144
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 conception ...
Posted: 03/11/2016 16:30:00 Hits: 143
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. Amo...
Posted: 03/07/2016 16:56:17 Hits: 149
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 temper...
Posted: 12/28/2015 14:45:39 Hits: 188
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 va...
Posted: 12/02/2015 16:18:09 Hits: 261
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 ring al...
Posted: 11/09/2015 15:57:54 Hits: 955
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 the ...
Posted: 10/23/2015 08:12:51 Hits: 1671
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 to the f...
Posted: 10/07/2015 17:19:48 Hits: 687
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 other ...
Posted: 09/19/2015 17:05:47 Hits: 877
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, it is ...
Posted: 09/11/2015 16:15:27 Hits: 545
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 and fle...
Posted: 09/04/2015 18:01:36 Hits: 427
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: 741
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 characte...