Definition of high pressure valve:

(1) The valve with absolute pressure lower than 1 atmospheric pressure is called vacuum valve;

(2) Pressure ≤ 1.6Mpa is called low pressure valve;

(3) The pressure of 2.5 ~ 6.4Mpa is called medium pressure valve;

(4) The pressure of 10.0 ~ 80.0mpa is called high pressure valve;

(5) Pressure ≥ 100.0mpa is called ultra-high pressure valve.

There are two working conditions for high-pressure valves. One is that the medium is at room temperature but the pressure is very high, such as valves for oil production and water injection in oil fields; The other is that the medium is at high temperature and high pressure, such as the main steam system valve used in thermal power plant. Although these two types are also "high pressure valves", the design criteria and material selection are different. The former only considers the strength and stiffness, while the latter should also consider the strength and creep of materials at high temperature.

Material selection of high pressure valve

1. Pressure bearing parts and pressure control parts

Valve parts can be divided into "pressure bearing parts" and "pressure control parts" according to their role in the whole valve. The following statements are made in American API6D "pipeline valve" standard:

Pressure bearing parts refer to parts designed to bear pipeline medium (pressure), such as valve body, bonnet, packing gland, valve stem, gasket and bolt;

Pressure control parts (pressure control parts) refer to parts used to block or allow medium flow, such as closing parts, valve seats, etc.

2. Shell material

The shell includes valve body, valve cover and other parts, which directly bear the medium pressure. It is the pressure bearing part of the valve. Its material must have the due mechanical properties and chemical composition under the specified medium, temperature and pressure, and have good cold and hot processing technology.

3. Valve stem material

The valve stem is one of the pressure bearing parts of the valve. During the opening and closing of the valve, it bears the tensile, compressive, shear and torsional forces and is in direct contact with the medium. At the same time, there is relative friction movement with the filler. Therefore, the valve stem material must ensure sufficient strength and impact toughness under the specified medium, temperature and pressure, and have corrosion resistance and scratch resistance that can meet the requirements, And good workmanship.

4. Sealing surface material

The sealing surface is the key part of the valve. The materials used for the sealing surface shall be corrosion-resistant, erosion resistant, scratch resistant, have sufficient extrusion strength (specific pressure), have sufficient oxidation resistance and thermal fatigue resistance at high temperature, and shall be close to the linear expansion coefficient of the base material and have good processing and welding processability. For the sealing surface of high-pressure valve, cemented carbide is usually used.

5. Materials of pressure bearing fasteners

Pressure bearing fasteners mainly refer to the connecting bolts and nuts of the middle flange, which directly bear the pressure of the medium on the valve and play an important role in preventing medium leakage. Therefore, the selected materials must ensure sufficient strength and impact toughness under the service pressure and temperature.

According to the provisions of GB / t150-1998, JB / t5300-1991, ASME b16.34a and other standards, the commonly used fastener materials of high-pressure valves include alloy steel and stainless steel.

★ 1. Alloy steel

Chinese standard: GB / T 3077 30crmoa, 35CrMoA, 40Cr, 25Cr2MoVA, 25cr2mo1va;

American standards: ASTM a193-b16, ASTM a194-7.

★ 2. Stainless steel

Chinese standards: gb1220 2Cr13, 0Cr18Ni9, 0Cr18Ni10Ti, 0Cr17Ni12Mo2

1Cr17Ni2、1Cr18Ni9、1Cr18Ni9Ti；

American standards: ASTM a193-b8, b8m, ASTM A194-8, 8m.

Packing and gasket materials

The packing and gasket used for the valve are the filler to prevent the leakage of medium. The packing is used to fill the space between the packing chamber and the valve stem to prevent the medium from leaking through the space between the valve stem and the packing chamber; The gasket is used to fill all irregularities between the two joint surfaces (such as the sealing surface between the valve body and the valve cover) to prevent medium leakage from the joint surface. Therefore, the requirements for filler materials are corrosion resistance, good sealing and low friction coefficient; The requirements for gasket materials are corrosion resistance, certain elasticity, plasticity and sufficient strength at working temperature.

Main standards for stop valves

① Gb12233-89 general purpose valves and iron globe valves

② Gb12235-89 general purpose valves flanged steel globe valves and lift check valves

③ JB / t53174-94 quality grading of stop valve products

④ JB / t53165-92 product quality grading of high pressure balance stop valve

⑤ Marine blue bronze globe valves (GB / t587-93)

⑥ GB / t590-93 marine blue iron globe valves

⑦ Gb8464-87 general technical conditions for gate, globe and check valves with internal thread connection

⑧ Gb8465.2-87 gate valves, globe valves, ball valves and iron globe valves with basic dimensions with internal thread connection

Main performance of stop valve

① Compared with, the regulating performance is better, but because the valve rod does not rise and fall from the handwheel, it is difficult to identify the regulating amount;

② The flow resistance is larger than that of gate valve, ball valve and;

③ Less sealing surface than gate valve;

④ The sealing performance is generally worse than that of the gate valve. For the medium containing mechanical impurities, the sealing surface will be vulnerable when the valve is closed;

⑤ The price is cheaper than the gate valve;

⑥ Suitable for steam medium; It is not suitable for medium with high viscosity, particles, easy coking and easy precipitation; Plug valve gate valve

In the 1950s, ball valves gradually appeared in the industrial production of western developed countries. And its utilization rate is increasing year by year, and people continue to improve its performance. Nowadays, in China, ball valves are mainly used in pharmaceutical machinery, petroleum refining, water conservancy and chemical industry, electric power, municipal paper, steel and other industries. These industries play a very important role in the national economy. Therefore, ball valves are also indispensable equipment in these industries.

How does the ball valve stand out

In the field of valves, there are many kinds of valves. The reason why ball valves can stand out and are frequently used in various fields is inseparable from their irreplaceable advantages. So, what are the advantages of ball valve?

First of all, the advantage of ball valve that can not be ignored is wear resistance. According to the technicians in the industry, for the valve, wear resistance is an important factor to test the quality of the valve. The sealing ring material of the ball valve is alloy steel surfacing, while the general valve sealing ring is rubber or other metals. These materials have no good wear resistance than the alloy steel surfacing of the ball valve.

"As we all know, the valve is a switch, which needs to be opened and closed. At the same time, the sealing ring will be greatly worn, but this will not happen to the sealing ring of the ball valve." the industry said.

Secondly, the sealing performance of the ball valve is very good. It is understood that the sealing of the ball valve is not ground by machine, but by manual grinding, which can ensure a higher degree of coincidence, so the sealing performance is very reliable.

In addition, the service life of the ball valve is very long. This is also a point that manufacturers pay great attention to relevant production equipment.

"Because it is often used in major production front-line industries, if its service life is not long enough and it needs to be replaced frequently, it will become very troublesome and cause a lot of mistakes."

Sharing of ball valve selection skills

As a kind of opening and closing part with the help of valve stem, the stability of equipment performance is very important. Therefore, some details need to be followed in the selection in order to better meet the actual needs.

Pay attention to size selection. It is understood that the flow resistance of ball valve is generally very small, and the channel and pipeline are almost the same, so it can be used in some areas sensitive to medium working conditions. When choosing this kind of valve, we should pay attention to the choice of size. Different sizes, different weights, and different effects can be achieved.

Reasonable consideration of price. When selecting the valve, in addition to comparing the goods, we should also consider the economy. As long as it can meet the actual demand, we don't have to choose a large size or heavy one.

In addition, fixed ball valves have closed valve cavities. If they are used in low-temperature media or in environments where gasification may occur, valves with relief devices must be selected. If necessary, the ball valve needs to be changed into butterfly valve or stop valve.

The industry pointed out that this valve is generally suitable for pipeline cutting with ball passing requirements. For the selection of such valves, if necessary, they can be selected according to the needs of channel structure, which can ensure to meet the needs of multiple channels and reduce the number of valves as much as possible.

It is worth reminding that the selection of ball valves also needs to pay attention to the selection of brands and prices. It is wise to choose valves with high cost performance.

Affected by the epidemic, 2020 is a challenging year for the environmental governance industry, but this year also has more special significance in the field of environmental protection equipment manufacturing, including pump pipe valves.

On the one hand, according to the industrial objectives formulated in the top-level design, the manufacturing of environmental protection equipment will usher in a new atmosphere by 2020, and the innovation driving system will be basically formed; On the other hand, the players in the field of pump pipe valve have also undergone profound changes this year, and the market is fiercer than ever before. As the person in charge of relevant enterprises said, "after the epidemic, what changes have taken place in the pump pipe valve industry and how are the enterprises? It can be seen from the registration heat of exhibitors revealed by the current environmental Expo and the world environmental Expo."

From a broader perspective, both "local players" and cross-border giants vaguely point to a future war, a competition on pump and pipe valves, environmental protection intelligent manufacturing, cost reduction and efficiency increase, and a competition and game on the right to speak in the market.

Where is the survival line when differentiation intensifies

"Environmental protection enterprises performed better than expected in the first half of the year, but we also saw that they still faced a severe situation in the second half of the year." even if they achieved higher than expected results, it does not mean that pump pipe valve enterprises can take a breath.

Under the superimposed influence of the concentrated release of production capacity in the environmental protection market and the continuous extension of the project boundary, the pattern of pump pipe valve segment market and enterprises is changing. After years of industry surge, what impressed the industry is that the head team of pump pipe valve industry has gradually formed, and the swarming small and medium-sized enterprises have also entered the stage of "industry reshuffle".

The smoke of gunpowder in the local pump pipe valve market has not dispersed, and the competition in the second half has already begun. The existing stock sector needs more specialized and refined pump pipe valve system services, and the survival line of the industry will be improved accordingly. Through the "wild era" of the pump pipe valve market, it seems that the pattern has been determined, but in fact it is still surging. Leading enterprises are also accelerating market penetration, shifting the focus of layout to third and fourth tier and township projects, and harvesting future emerging markets based on radiation breadth and network layout. More small and medium-sized pump and pipe valve enterprises are changing from OEM manufacturers to original design manufacturers and brands.

This is only a microcosm of the changes in the pump pipe valve equipment industry.

Grab incremental space

Another more and more obvious trend is that pump pipe valve enterprises are becoming more and more interested in comprehensive and large market cakes. Compared with the previous form of equipment manufacturing, today's pump pipe valve project can not be completed with a single delivery of equipment. Under the background of project integration, the advantages of single project for pump pipe and valve equipment enterprises are no longer prominent, including plant network integration and comprehensive environmental protection bundling and packaging project has become a trend.

"The epidemic has given birth to more online opportunities and changed the order structure. The customized service with short cycle and small batch has become a new trend for pump and pipe valves." the industry believes that Internet marketing not only breaks the "flower board" of many pump and pipe valve manufacturers with poor marketing channels and difficult transformation and upgrading, but also gives birth to enterprises relying on technological innovation and independent brands, The demand and power to comprehensively improve the product chain and management capability.

Benefiting from this, the market scale and imagination of pump pipe valve may be more than the former. Or because of this, a new round of predators began to enter the game. As the person in charge of the relevant pump and valve enterprises who will appear at the world environmental protection conference said, "each enterprise is still looking for incremental space and divides the 'gold digging points' according to the resources at hand." different from the past, this time, the bet is who can live in the escalating knockout competition!

Starting from "new" in the second half

The imagination space of traditional pump pipe valve equipment manufacturing has gradually approached the ceiling, and the imagination of intelligent manufacturing of environmental protection equipment based on this has just begun. With the end of the pump pipe valve qualification competition, the next round opportunity window for all contestants in the field of improving the benefits of pump pipe valves has been opened.

From the perspective of the development of environmental protection equipment manufacturing industry, pump pipe valve equipment is entering a new round of transformation period of renewal and iteration, and more differentiated, systematic and lean needs are gradually incorporated into the supply and demand side, which is not only a challenge to pump pipe valve enterprises, but also a great opportunity for the industry. Originality, cost reduction, efficiency enhancement and comprehensive service, the opportunities and unlimited possibilities behind the pump pipe valve are being stimulated step by step.

Although the essence of taking cost reduction and efficiency increase as the core has become the standard configuration of pump pipe valve equipment and overall solutions, and even is regarded as a sharp tool to seize the market opportunity, reviewing the development process of pump pipe valve industry is far less valued than at present. Back to the beginning of the birth of the pump and pipe valve market, there was not much technical gap between enterprises at that time. Pump and pipe valve manufacturing has always been a low threshold industry. Many enterprises that enter the pump pipe valve do not survive by relying on the competitiveness of technical hard core, market positioning and business model innovation.

"Any transformation is a rebirth, and the pump, pipe and valve equipment industry chain is no exception." respondents generally believe that in the face of the rapidly changing market environment, the only way to remain unchanged is to consolidate the "new content". Only the independent brand moving forward against the wind, a clear development route and differentiated layout can build a strong main body for the high-quality development of the pump pipe valve industry.

Pump pipe valve, the hot land of Xinzhi manufacturing, is gradually taking shape.

Woci valve (Shanghai) Co., Ltd. - brand valve manufacturer, professional valve manufacturer!