The difference between a high temperature one piece ball valve and a ball blowdown valve

Resistance to high temperatures was a big difference before them.

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 influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, 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 the user's stove.

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 changing rapidly, and the rankings may vary by time and region. For the latest ranking information, it is recommended to refer to industry reports, professional institutions or market research data for more detailed and accurate information.

First, the main difference between high-temperature ball valve and normal temperature ball valve The manufacturing process is different, and second, the difference in sealing: Generally, the normal temperature ball valve is a soft sealed valve seat; High temperature is a hard seal (metal or mechanical carbon and ceramic, etc.), and the material of the valve trim is better than the soft seal, three, material treatment: generally the normal temperature ball valve lathe can directly enter the assembly after processing; High-temperature ball valves also need to be treated (because the treatment process of different materials is also different, such as nitriding, spraying, etc., which will not be detailed here).

4. Assembly: Generally, the normal temperature ball valve can be assembled after getting the parts; High-temperature ball valves need to grind the ball core and valve seat, and this sequence is also critical, and the size of the leakage depends on grinding.

The high-temperature ball valve is suitable for working under high temperature conditions, and the performance of ordinary ball valves will be reduced or even lost at high temperature; The names in the two different classifications of stainless steel ball valves and high-temperature ball valves are not comparable.

Ball valve refers to a valve in which the opening and closing parts (balls) are driven by the valve stem and rotate around the axis of the ball valve.

Ball valves can be classified according to various ways such as driving mode, function, use, structure, valve body material, sealing form, applicable occasions and so on. Among them, the stainless steel ball valve is the name classified according to the material of the valve body, and the high-temperature ball valve is the name classified according to the applicable occasions.

In the strict sense of the word, there is no such thing as a "normal" ball valve. However, the largest amount used in practical applications is the one-way soft-seal floating ball valve. The sealing material of this type of ball valve is made of plastic, which is easy to seal, easy to process, and low in cost, but it is easy to deform and damage the sealing material at high temperatures, resulting in leakage.

High temperature ball valve refers to the use of ball valves with high temperatures. In fact, what is high temperature is different in different occasions and standards, and there is no strict definition. Generally speaking, if the plastic sealing material is used, it can work to 160 or more, and it can be called "high temperature", but the sealing form is often stated at the same time; The ball valve using metal elastic material as the seal (soft seal) can withstand a temperature of about 300 meters; Ball valves that can be used in 420 and above are all metal hard sealed.

The difference between these two is relatively big, whether it is the difference in material, as well as the performance, and the selection, it is very different, such as the ordinary 304 stainless steel ball valve of the Qigao valve bought by our company, I see that the temperature resistance they wrote is 180 degrees, and then there is a batch of high-temperature ball valves, they choose high-temperature materials, the temperature and weight of the product, the seal material, and the body shape are not the same, the valve industry still has technical content!

The high-temperature ball valve is a metal seal structure, and the sealing form is loose metal-to-metal seal, replaceable metal grinding hole seal ring to metal seal, stainless steel plate and graphite composite plate seal to metal seal. In addition to electric, the driving forms of hard seal butterfly valves include manual, worm gear rod transmission, pneumatic, etc. The butterfly plate of the high-temperature ball valve is installed in the diameter direction of the pipe.

In the cylindrical channel of the hard seal ball valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°, and when the rotation reaches 90°, the valve is fully open.

At present, corrosion-resistant ball valves and hard-sealed butterfly valves, as a component used to realize the on-off and flow control of pipeline systems, have been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower, etc. In the well-known butterfly valve technology, its sealing form is mostly a sealing structure, and the sealing materials are rubber, PTFE, etc. Due to the limitation of structural characteristics, it is not suitable for high temperature resistance, high pressure resistance, corrosion resistance, wear resistance and other industries.

At present, a relatively advanced butterfly valve is a three-eccentric metal hard seal butterfly valve, the valve body and the valve seat are conjoined components, and the surface layer of the valve seat seal is welded with temperature-resistant and corrosion-resistant alloy materials. The multi-layer soft-stacked sealing ring is fixed on the valve plate, this butterfly valve has high temperature resistance, light operation, no friction in opening and closing, and compensates for the sealing with the increase of the torque of the transmission mechanism when closing, which improves the sealing performance of the butterfly valve and prolongs the service life.

First, the advantages and disadvantages of ball valves.

1. Advantages: It has the lowest flow resistance (actually 0);

Because it does not get stuck during operation (without lubricant), it can be reliably used in corrosive media and low-boiling liquids;

In the range of large pressure and temperature range, it can achieve complete sealing;

It can be opened and closed quickly, and the opening and closing time of some structures is only to ensure that it can be used in the automation system of the test bench. When the valve is opened and closed quickly, there is no impact in operation;

The spherical closure can be automatically positioned at the boundary position;

The working medium is sealed and reliable on both sides;

In the case of fully open and fully closed holes, the sealing surface of the ball and the valve seat is isolated from the medium, so the medium passing through the valve at high speed will not cause the erosion of the sealing surface;

With its compact structure and light weight, it can be considered as the most reasonable valve structure for cryogenic media systems.

The symmetry of the valve body, especially the welded valve body structure, can well withstand the stress from the pipeline;

The closing part can withstand the high differential pressure when closing;

The ball valve with the all-welded valve body can be buried directly in the ground, so that the valve internals are not corroded, and the maximum service life can reach 30 years, which is the most ideal valve for oil and gas pipelines.

2. Disadvantages: Because the most important seat sealing ring material of the ball valve is PTFE, it is inert to almost all chemical substances, and has the comprehensive characteristics of small friction coefficient, stable performance, not easy aging, wide range of temperature application and excellent sealing performance. However, the physical properties of PTFE, including a high coefficient of expansion, susceptibility to cold flow, and poor thermal conductivity, require that seat seals be designed around these properties.

So, when the sealing material hardens, the reliability of the seal is compromised. Moreover, PTFE has a low temperature resistance rating and can only be used in cases less than 180. Beyond this temperature, the sealing material will deteriorate.

In the case of long-term use, it will generally only be used at 120.

Its regulation performance is somewhat inferior to that of shut-off valves, especially pneumatic valves (or electric valves).

2. Scope of application:

Ball valves are used in petroleum refining, long-distance pipelines, chemicals, papermaking, pharmaceuticals, water conservancy, electric power, municipal, steel and other industries.