What is the structure of the national standard globe valve, and what is the structure of the globe v

The structure of the globe valve body is straight-through, direct flow and right-angle. Straight-through is the most common structure, but its fluid has the most resistance. The direct flow fluid has less resistance and is mostly used for fluids containing solid particles or high viscosity.

The right-angle valve body is mostly forged, which is suitable for shut-off valves with small passage and high pressure.

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following are the top ten domestic first-line valve brand manufacturers in 2022-2023, but for reference only: Suzhou Neway Valve Co., Ltd., Shanghai Guanlong Valve Machinery, Shanghai Qizhong Valve Manufacturing, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

The globe valve is mainly composed of six parts, including the valve stem, the valve body sealing gasket, the handle, the valve body, and the valve cover, as shown in the following figure

The opening and closing parts of the globe valve are plug-shaped discs, and the sealing is flat or sea cone, and the disc moves in a straight line along the center line of the valve seat. The movement form of the valve stem, (common name: dark rod), there are also lifting and rotating rod types, which can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media.

The stem or mega axis of the globe valve is perpendicular to the sealing surface of the valve seat. The relatively short opening or closing stroke of the stem and the very reliable shut-off action make this valve ideal for use as a shut-off or adjustment and throttling of the medium.

Once the disc of the globe valve is opened, there is no longer any contact between the seat and the sealing surface of the disc, and it has a very reliable shut-off action, which is very suitable for the use of shut-off or adjustment and throttling of the medium.

Once the globe valve is in the open state, there is no longer contact between the valve seat and the sealing surface of the valve disc that it rents, so the mechanical wear of its sealing surface is small, because the valve seat and disc of most globe valves are relatively easy to repair or replace the sealing elements without removing the entire valve from the pipeline, which is very suitable for the occasion where the valve and the pipeline are welded into one. The flow direction of the medium through these valves changes, so the flow resistance of the globe valve is higher than that of other valves.

Commonly used globe valves are as follows:

1) Angle shut-off valve

In an angle globe valve, the fluid only needs to change direction once, so that the pressure drop through this valve is smaller than that of a conventional globe valve.

2) DC shut-off valve

In a flow-through or Y-type globe valve, the flow channel of the valve body is inclined to the main channel, so that the degree of damage to the flow state is less than that of the conventional globe valve, so the pressure loss through the valve is correspondingly smaller.

3) Piston globe valve

This form of globe valve is a variation of a conventional globe valve. In this valve, the disc and seat are usually designed based on the plunger principle. The disc is ground into a plunger connected to the stem, and the seal is achieved by two elastic seals that are sleeved over the plunger.

The two elastomeric seals are separated by a collar and are pressed against the seal around the plunger by a load applied to the bonnet by the bonnet nut. Replaceable seals can be made of a wide variety of materials, and the valve is mainly used for "on" or "off", but is available with a special form of plunger or a special collar that can also be used to regulate the flow rate.

The globe valve is a valve that uses the stem to lift and drive the valve head, thereby changing the distance between the valve disc and the valve seat to achieve opening and closing control, and the globe valve is the most widely used cut-off valve in chemical production. The globe valve is mainly used for the control of water, steam, compressed air and other pipelines in actual production, but it is not suitable for materials with high viscosity and easy to crystallize.

The structure of the globe valve is more complex, but the actual operation is simple and labor-saving, and it has good performance in adjusting the flow rate and cutting off the channel, and the opening and closing speed is slow and water hammer rarely occurs. The structure of the globe valve is compact, the shape has obvious characteristics, the top of the valve is provided with a handwheel and a valve stem, and the middle is provided with a thread and a stuffing box sealing section.

The main way to judge the opening and closing state of the valve when the globe valve is in use is to observe the height of the valve stem exposed to the bonnet, so as to control the operation of the valve. There may be voids in the part where the stem joins the bonnet, which is prone to media leakage, which can be addressed with packing seals. The stem thread of the small globe valve is located in the valve body, so it is easy to be corroded by the medium for a long time in the use of the blade.

The installation of the globe valve should refer to the direction of the fluid, and pay attention to keeping the fluid in the pipeline low in and high out, that is, flowing through the valve seat port from the bottom to the top. The purpose of this installation is to reduce the fluid resistance in the valve body and thus reduce the opening and closing force of the valve, and at the same time, it can also keep the valve stem and stuffing box from contact with the medium when the valve is closed, and reduce the occurrence of damage and leakage.

When using the globe valve, the following three points should be noted:

1. Before opening the globe valve, a leakage check should be carried out to determine whether the valve has no leakage defects and whether the stuffing box has no leakage defects.

2. If the stem operation of the globe valve cannot be completed by hand, a special F wrench can be used instead, but in the case that the F wrench still cannot be opened, do not use an extension wrench to forcibly open and close to avoid damage to the valve or even the occurrence of safety accidents.

3. When the globe valve is applied to the medium pressure steam pipeline, the condensate needs to be removed before opening, and then the steam is preheated on the pipeline, and the preheating pressure is kept between to, the purpose of this is to avoid damage to the seal caused by sudden changes in temperature and pressure, and the pressure can be adjusted to the required level after determining the stability of the state.

The globe valve is one of the more common pipe fittings in our life, which acts as our valve. Its role in different industries and to go is also different, although there are many types in our lives, but as one of the fasteners, there are certain standard requirements. Moreover, the production standards of different countries are also different, and this article will briefly introduce the requirements of different standards for you.

What are the standards for globe valves.

1. National standard globe valve.

The national standard globe valve is only suitable for full opening and full closing, and is generally not used to adjust the flow rate, and is allowed to adjust and throttle when customized. The standard implemented by the national standard globe valve is the design specification: GB T12235, and the structural length:

GB T12221, flange connection: JB T79, test and inspection: JB T9002, product identification:

gb/t12220；The structure of the national standard globe valve is simple, and the manufacturing and maintenance are relatively convenient; Its working stroke is small, and the opening and closing time is short; Good sealing, small friction between sealing surfaces, long life.

Second, the German standard globe valve.

The German standard globe valve is a bellows-sealed zero-leakage globe valve with a leakage class of 6, which can meet the requirements of most working conditions. It is mainly used in various toxic fluids, precious fluids, corrosive media and other high-demand pipeline systems that do not allow leakage. Its product specifications Fan's Shield:

DN15-DN300, operating temperature range; Pressure Range:; Main materials: WCB L, LCB, LCC, duplex steel, etc.

3. American standard globe valve.

The American standard globe valve adopts a double sealing structure: the layer-type seal is imported high-quality alloy bellows, and the second valve stem packing is used as a secondary seal, which usually does not contact with the medium. The design and manufacture of the products meet the requirements of foreign advanced standards such as the American National Standard and the British National Standard BS1873.

The external shape of the body is barrel-shaped or streamlined, the shape of the flow channel is straight-through, and the fluid resistance is small. The valve seat can be a more replaceable valve seat, and can be matched with the sealing surface material of the closing part in any combination to meet the requirements of various working conditions and prolong the service life.