With all kinds of complete sets of equipment, process and performance improvement, foreign valve series varieties are still increasing, in recent years there have been many new varieties of valves. Such as: emergency shut-off valve, fast switch valve, fire valve, anti-static valve, temperature reducing valve, butterfly check valve, pressure relief valve, vacuum jacket valve, water-cooled or air-cooled valve, safety gate valve, safety globe valve and other new valves, including general valve ball valve, butterfly valve and flat gate valve is 20 years of rapid development of valve varieties. At present foreign high valve basic technical parameters.

Quality level of valve products at home and abroad

A. Sealing reliability. Foreign countries specify the use and selection of products according to the degree of sealing of the closing parts, and classify the degree of sealing, which is generally divided into three grades. 1. level 2 is used for places with high sealing requirements, and level 3 is used for general medium and low pressure industrial valves. Although the leakage values are not the same, there are leakage regulations. Foreign valve leakage have standards.

B. valve a switch time. Some valves are required to open or close in a very short time. The length of a switch marks the performance of the valve. The switching time of some valves in the United States has reached the level of milliseconds. For example, AMES Research Center only needs 1ms to open a 6-inch 300-pound gate valve, medium diameter DN350 ~ 400 fast on-off valve only needs 0.6s, and the time to open and close ball valve reaches 0.05 ~ O.1s, which is made by Okano Valve Company of Japan.

Speed high temperature valve, one opening time is 1s, the medium is air, DN40,PNl4MPa, the working temperature is 1267 ℃, the medium flow rate is 11 times the speed of sound, 3640 m/s.

Casting: foreign castings for cupola and electric furnace double, cast steel for electric furnace and refining. The liquid metal is of high quality, stable chemical composition, resin sand is molded, moisture film automatic line or mechanical modeling (mechanized modeling accounts for about 50%) is mostly controlled by microcomputer, advanced equipment, high dimensional accuracy of castings, smooth surface and good sand cleaning methods.

Forging: most foreign countries use die forging, and have adopted multi-directional die forging and closed film forging. The quality of forgings is high, and the material utilization rate can reach 95%. Large forging diameter up to DN500.

Heat treatment: most of the heat treatment abroad has been controlled heat treatment. For example, Japan's controllable treatment has accounted for about 70% and 80%, and some use vacuum heat treatment. Nitriding also uses ion nitriding, soft nitriding, chemical treatment and other new processes.

Mechanical processing: foreign processing equipment has been automated, numerical control and has adopted processing centers, while others have applied group control equipment for processing, generally using group technology and machine clamp tools, digital measuring tools, equipped with special cleaning assembly workshops, advanced and complete testing devices, and advanced leakage detection methods.

Specifications and technical standard level

From the specifications, Japan has about 8000 specifications, the former Soviet Union has 28000 specifications, many valves are based on the change of materials, connection type and size to form a variety of "derived valves". The world's industrial developed countries produce as many as a hundred kinds of valve materials, steel castings have as many as 60 kinds of 5., especially ultra-low carbon steel series a lot of rapid development, and thus foreign valve products have a strong ability to adapt. To this end, the corresponding valve standards are also many, only the former Soviet Union has 355 items, Germany has 177 items, France 117 items, etc., foreign technical standards focus on product performance, quality and reliability and other comprehensive indicators.

Analysis of the future development trend of global valve products

With the development of foreign large-scale complete sets of technology, a series of new complete sets of equipment and stand-alone. The development of new complete sets of equipment related to valves is characterized by large-scale, high-parameterization, high-performance automation and complete sets, which are compatible with the control methods of these complete sets of equipment. In the past 20 years, foreign valve control methods have also developed greatly. In addition to the general manual, motorized, electric, pneumatic, hydraulic transmission, electro-hydraulic linkage, gas-liquid linkage, automatic control of the valve variety is increasing, and there is a trend of further development.

such as oil refining equipment. The refinery is 36.4 million tons/year (Virgin Islands in the Caribbean) and 30 million tons/year (Venezuela). At present, there are nearly 30 refineries with more than 20 million tons/year; the processing capacity of the unit refining decompression unit reaches 24 million tons/year, the catalytic cracking unit reaches 8.24 million tons/year, and the hydrocracking unit reaches 3.2 million tons/year. The large-scale device forces the valve to become larger and larger, and the control method also begins to develop in the direction of automation.

In recent years, long-distance pipelines have developed rapidly. The main reasons are low cost, which is only equivalent to 1/3 of railway transportation; the second is that they are buried underground and are not easy to destroy; the third is that the pipeline construction speed is fast and investment is saved. Therefore, the demand for long-distance pipeline valves has increased greatly in recent years. The unit capacity of power generation equipment is 300000 kW for double-shaft thermal power unit l, 1.2 million kW for single-shaft thermal power unit and 1.3 million kW for nuclear power unit.

In the valves matched with these complete sets of equipment, the diameter of the flat gate valve reaches 1620mm and 2000mm; Butterfly valve diameter 9750mm; Ball valve diameter 3050mm, not counting the weight of the driving device valve reached 184 tons; Water gate valve has a diameter of 2750mm and a pressure of 9MPa.

The economic effect of large-scale equipment can be summed up, one is to improve production efficiency, the other is to reduce infrastructure investment, and the third is to reduce the consumption of raw materials. Compared with 1 million tons of refining equipment with an annual processing capacity of 5 million tons, the investment per ton of product production capacity is reduced by 50%. Compared with two 3 million ton/year refineries, the investment of a 6 million ton/year refinery is only 69% of the latter, the steel consumption is 53%, the floor area is 54%, the production cost is 75%, and the labor productivity is increased to 170.

Due to the increasing level of automation of complete sets of equipment, foreign petrochemical enterprises have realized direct digital control of the main production process, and some have also realized computer classification control. Ammonia ethylene, urea, synthetic fiber, synthetic rubber and synthetic plastics and other chemical enterprises generally realize circuit detection, alarm, and some enterprises have realized part of the automation control.

At present, foreign large-scale generator sets above 200000 kW are generally developed to computer control. Nuclear power plants are generally controlled by computers. Many countries use computer control for long-distance pipeline systems and are equipped with microwave communication systems. The general control room only needs two or three personnel on duty to monitor the working conditions of the whole line through television.