Junior valve scholars, valves can be divided into several categories according to their use

At least you have to tell you what position you are in, no matter what, you must always be familiar with the basic knowledge of valves, and the regular company should also provide training and the like, and you yourself should also consult your company's technical personnel.

What kind of valve are you referring to, I have the basic knowledge of control valves, if you want to tell the mailbox, send it to you.

Want to know the fastest and most familiar about the valve not?

Go work as an installer for two weeks! Preferably on the construction site! Ask more! You don't have to take two weeks' wages!

You'll know pretty much that!

I have some in my space, and they will be improved quickly in the near future!

Hello! Depending on your situation, you can't apply for the assistant engineer exam yet. The application requirements clearly stipulate that you can apply for the examination one year after graduating from the undergraduate engineering category, and you can apply for the examination three years after graduating from the junior college category, and you must have a work certificate issued by the unit.

Keep up the good work. By the way, what kind of valve did you design? I'm also a peer, 3 years old.

According to the classification of use, it can be divided into check valves, shut-off valves, vacuum valves, regulating valves, and special-purpose valves

1. Check valve.

This type of valve is used to prevent the backflow of the medium, and uses the fluid's own kinetic energy to open itself and close automatically when flowing in the opposite direction. Standing at the outlet of the pump, the outlet of the trap, and other places where the reverse flow of fluid is not allowed. There are three types of check valves: rotary opening type, lifting type and clamp type.

In the case of swing check valves, the fluid can only flow from left to right and automatically closes when it flows in the opposite direction.

In the case of lift check valves, the spool lifts up to create a path as the fluid flows from left to right, and the spool closes when it is pressed onto the seat when the flow is reversed. For the clamp-on check valve, when the fluid flows from left to right, the valve core is opened to form a path, and the valve core is pressed to the valve seat and closed when the reverse flow, and the clamp-on check valve can be installed in multiple positions, small in size, light in weight and compact in structure.

2. Shutdown valve.

This type of valve is used for opening and closing. It is permanently installed in the inlet and outlet of cold and heat sources, the inlet and outlet of equipment, and the branch line of pipelines (including risers), and can also be used as a water drain valve and air release valve. Common shut-off valves include gate valves, globe valves, ball valves and butterfly valves.

According to the flow direction of the medium, the globe valve is divided into three types: straight-through type, right-angle type and direct flow type, and there are open rods and dark rods. The closing tightness of the globe valve is better than that of the gate valve, the valve body is long, the flow resistance is large, and the maximum nominal diameter is DN200.

The spool of the butterfly valve is a round disc that rotates along the vertical shaft of the vertical pipe axis. When the plane of the valve plate is consistent with the axis of the pipe, it is fully open; When the ram plane is perpendicular to the axis of the pipe, it is fully closed. The butterfly valve body length is small, the flow resistance is small, and it is higher than the gate valve and the globe valve.

3. Vacuum valve.

Vacuum includes vacuum ball valves, vacuum baffle valves, vacuum inflation valves, pneumatic vacuum valves, etc. Its function is in the vacuum system, the vacuum system element used to change the direction of the air flow, adjust the air flow volume, cut off or connect the pipeline is called the vacuum valve.

Fourth, the regulating valve.

The pressure difference between the front and rear of the valve is certain, and when the opening of the ordinary valve changes in a large range, the flow rate changes little, and when it reaches a certain opening, the flow rate changes sharply, that is, the adjustment performance is poor. The control valve can change the spool stroke to change the resistance of the valve according to the direction and size of the signal, so as to achieve the purpose of regulating the flow valve.

Control valves are divided into manual control valves and automatic control valves, and there are many types of manual or automatic control valves, and their adjustment performance is also different. Automatic control valves include self-operated flow control valves and self-operated differential pressure control valves.

5. Special purpose.

Special purpose categories include pig valves, vent valves, sewage valves, exhaust valves, filters, etc. Exhaust valve is an indispensable auxiliary component in the pipeline system, which is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. It is often installed at the commanding height or elbow to remove excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption.

Valves can be divided into shut-off valves according to their uses; regulating valves; Protective valves. The function of the shut-off valve is to isolate the fluid in the pipeline.

The function of the regulating valve is to change the parameters of the medium in the pipeline. The function of the protective valve is to protect the safety of the equipment, prevent the overpressure of the pressure vessel or prevent the reverse flow of the medium.

It can be used as a valve for shut-off, a valve for regulation, and a valve for protection. Valves for shut-off include gate valves, globe valves, butterfly valves, plugs and diaphragm valves. Regulating valves include throttle valves, pressure regulating valves, water level regulators and water traps.

There are more of them, which can be divided into:

Shut-off valve. Check valves.

Control valves. Vacuum.

Special Purpose Category.

By nominal pressure:

1) Vacuum valve: refers to the valve whose working pressure is lower than the standard atmospheric pressure. (2) Low pressure valve:

Refers to a valve with nominal pressure pn. (3) Medium pressure valve: refers to the valve with nominal pressure pn.

4) High-pressure valve: refers to the valve with nominal pressure pn. (5) Ultra-high pressure valve:

Refers to a valve with nominal pressure pn.

By operating temperature:

1) Ultra-low temperature valve: a valve for medium operating temperature t< 101. (2) Normal temperature valve: a valve used for the medium working temperature of 29 425.

By Drive Type:

According to the driving mode, it can be divided into automatic valves, power drive valves and manual valves.

According to the nominal diameter.

1) Small bore valve: valve with nominal bore DN 40mm. (2) Medium bore valve:

Valves with a nominal diameter of 50 300mm. (3) Large diameter valve: valve with nominal diameter DN of 350 1200mm.

4) Extra-large bore valve: valve with nominal bore DN 1400mm.

The structural characteristics of the valve can be divided into the following according to the direction of the shut-off relative to the movement of the valve seat

1) Truncated door shape: the closing part moves along the center of the valve seat; Such as globe valve (2) and spherical: the closing part is a plunger or ball, rotating around its own centerline; Such as plug valve, ball valve (3) gate type:

The shut-off moves along the center of the vertical seat; Such as gate valves, gates, etc. (4) swing type: the closing part rotates around the shaft outside the valve seat; (5) Butterfly shape, such as swing check valve: the disc of the closing piece rotates around the shaft in the valve seat; Such as butterfly valves, butterfly check valves, etc. (6) spool valve shape:

The closure slides perpendicular to the channel. Such as slippery.

By connection method.

1) Threaded connection valve: The valve body is equipped with internal or external threads, which are connected with the pipeline thread. (2) Flange connection valve:

The valve body is flanged and connected to the pipe flange. (3) Welded connection valve: the valve body has a welded groove, which is welded with the pipeline.

4) Clamp connection valve: the valve body is equipped with a clamp mouth, which is connected with the pipe clamp. (5) Ferrule connection valve:

Ferrule connection (6) clamping connection valve with pipeline: the connection form of directly clamping the valve and the two pipes together with bolts.

By body material.

1) Metal material valve: its valve body and other parts are made of metal materials. Such as cast iron valves, cast steel valves, alloy steel valves, copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves, etc.

2) Non-metallic material valve: its valve body and other parts are made of non-metallic materials. Such as plastic valves, enamel valves, ceramic valves, FRP valves, etc.

Tianjin is one of the main valve producing areas in China, mainly butterfly valves, the quality belongs to the upper middle level, and the first is relatively affordable.

There are a lot of valves produced, such as Huquan in Shanghai, Bell in Yangzhou, Beijing, Zhejiang, etc., the specific ** is not the same, I have bought it in Shanghai, I personally feel that the quality of Shanghai Huquan valve factory is not bad, the service is good, and the shelf life and maintenance time is long. You can refer to it.

The quality of valves in Suzhou, Jiangsu Province is okay.

The valve in Wenzhou, Zhejiang Province is more favorable.

Generally, the design service life of the valve is 20 to 30 years, but the repair and replacement is about 10 years.

Look what valve you want, in terms of material, most of the Botou and Fujian production is ductile iron, Yuhuan out of copper valves, Wenzhou area is dominated by stainless steel and cast steel, in general, what valve you want, for reference only.

This problem is too big, the United States bray valve, the world's valve manufacturers.

Abroad: Yamatake, Japan.

Fisher, USA.

Siemens, the Netherlands.

German ABB and so on.

Domestic: China Ordnance "Yanke" ZPZD3100 intrinsically safe intelligent valve positioner ZPZD3110 flameproof intelligent valve positioner.

Chongqing Chuanyi and so on.

Intelligent valve positioner brands abroad mainly include: Japan Yamatake, the United States Fisher, the Netherlands Siemens, Germany ABB, etc., domestic is not much, this year to replace imports, break the monopoly, mainly Chinese weapons "Yanke" ZPZD3100 intrinsically safe intelligent valve positioner, ZPZD3110 flameproof intelligent valve positioner, Chongqing Chuanyi, etc.

Yamabu Fisher.

Siemens ABB

Yamatake, Siemens, ABB, Fisher, and many more.

Yes, it means the field pressure gauge and its primary valve (i.e. protection valve).

C. Question analysis: The question asks about "social factors", and AB is a political factor, which does not meet the requirements of the question. "The power of the gatekeepers of this era has fully demonstrated their advantages economically, socially, and politically.

By virtue of the shadow of their ancestors, they not only monopolized the right to elect officials, but all the officials in charge of the election interpretation of the state and county must be selected and appointed by them" and the meaning of option d is repeated.

On the water separator is to control the underfloor heating, and on the main pipe is to control the inlet water heater, and the return water heater