The hottest special plug valve breaks the foreign

  • Detail

Special plug valves have broken foreign monopolies, and China has lost one more item in the field of choking. In the past decade, China's oil and gas pipeline industry has achieved rapid development. In terms of pipeline length, the total mileage of oil and gas pipelines has reached 106000 kilometers, including about 26000 kilometers of crude oil pipelines, about 20000 kilometers of finished oil pipelines, and about 60000 kilometers of natural gas pipelines. In addition to pipelines, the construction of such a long mileage of oil and gas transportation pipelines,

in the past decade, China's oil and gas pipeline industry has achieved rapid development. In terms of pipeline length, the total mileage of oil and gas pipelines has reached 106000 kilometers, including about 26000 kilometers of crude oil pipelines, about 20000 kilometers of finished oil pipelines, and about 60000 kilometers of natural gas pipelines. In addition to pipelines, there is an essential component - valves in the construction of such a long-distance oil and gas transportation pipeline

(I) special plug valves have been monopolized by foreign countries for a long time, threatening energy security

the importance of valves in oil transportation is basically equal to the importance of taps for tap water supply, and the length of China's oil pipeline determines that the number of valves used is not small. However, due to the high technical threshold of this special plug valve used in product oil transportation pipeline, for a long time, the plug valves used in China have depended on imports, which is not only expensive and expensive to maintain, but also a major hidden danger to China's energy security

but now, the localized plug valve has successfully entered the medium and high-end market, the manufacturing cycle is only half that of foreign products, and it can provide 48 hours of on-site after-sales service, which greatly saves the construction and maintenance cost of China's oil pipeline

(Application of plug valve)

(II) domestic plug valve design: sealing performance and service life are no longer contradictory

you may ask, is it not a valve? What is the high technical content? What's the difference with valves like household faucets

the main application of valves is to ensure good opening and closing, which has high requirements for the sealing performance of valves

1. Traditional valves: sealing and supply side reform accelerate production capacity and clear service life. It is difficult to have both.

usually, the pipeline valves we see are like this:

in the process of operation, the traditional valves determine the opening and closing of the pipeline through the rotation of the seals in the valve cavity. Therefore, the friction of the seals caused by the rotation is inevitable, resulting in wear. The tighter the seal is, the more serious the wear will be, The shorter the service life, even with lubrication measures, this contradiction cannot be completely avoided. Over time, the sealing performance will naturally decline, and even lead to the failure of the valve seal

if the faucet or valve leaks, we can replace it, but if the product oil is transported, it is not so simple

2. Domestic oil and gas pipeline plug valve: the telescopic structure makes the absolute sealing and prolonging the service life no longer contradictory

the product oil transportation pipeline requires the plug valve to extend the effective service life as much as possible while ensuring the absolute sealing. This seemingly "fish and bear's paw can't have both" requirement is the key to the problem

(the excavation of domestic plug titanium alloy and resin basic complex materials poses a severe challenge to aluminum alloy)

so how can domestic plug valves meet such stringent requirements

first, let's take a look at the sectional drawing of the main structure of the plug valve:

(sectional diagram and structural drawing of the plug valve)

it can be seen from the drawing that the plug is a wedge (trapezoidal) structure, and the blank part in the middle is a fluid channel. Sliding plates for sealing are fixed on both sides of the cock. When the sealing sliding plate is closely connected with the valve body, the sealing condition is good

different from the general opening method of direct rotation of the valve, when the valve is opened, the valve operator first lifts the wedge-shaped plug for a certain distance, so that the sealing sliding plate fixed on the plug will also be separated from the valve body. Then, when the sealing sliding plate and the valve body are not in contact with each other, and the Chinese plastic extruder industry is moving towards a healthy and sustainable contact, turn the cock 90 degrees to align the cock channel with the pipe, and the cock valve is opened

similarly, when closing, the operator first makes the plug and sliding plate rotate 90 degrees reversely without contact between the seal and the valve body, and then makes the plug move downward. The wedge action makes the sliding plate closely fit with the valve body to form a bubble level seal

to sum up, compared with the operation process of direct rotation of traditional valves, this plug valve also increases the process of upward lifting and downward compression. This unique telescopic structure design enables the sealing surface between the sliding plate and the valve body to be completely disengaged during the rotation of the plug, eliminating the wear between them, ensuring good sealing effect and prolonging the service life of the valve. At the same time, due to the effective elimination of friction between the sealing surfaces in the structural design, the plug does not need lubrication, avoiding the pollution of the finished oil medium

how about being shocked by the designer's clever design ideas

(III) domestic plug valve manufacturing: independent innovation of a number of key technologies

with design ideas is not enough, and many problems need to be solved in the actual manufacturing process

1. Structural design of closing secondary seal: Vacuum vulcanization, special anti-corrosion to ensure sealing performance

the most critical index in the structural design and manufacturing process of main valve is sealing performance

we know that the sealing material used for valve switches is usually rubber, but in the transportation pipeline of product oil, simple rubber sealing may not be enough. Because the product oil is an organic solvent, it will dissolve the rubber to a certain extent over time, making the seal ineffective

therefore, advanced processes such as vacuum vulcanization and special anti-corrosion are adopted on the sealing sliding plate, and the fluororubber sealing ring is permanently embedded into the metal matrix to form the main seal, so as to ensure the good sealing effect and long service life of the sealing sliding plate

(sealing sliding plate waiting for assembly)

the main valve closing pair adopts the split structure of seals and cocks. The sealing sliding plate with fixed special rubber is connected through the dovetail groove on the wedge-shaped cock to form a complete closing pair structure like the following figure

(cock and sealing sliding plate)

such a special shape cock has another advantage. Its structure can realize the self-locking function of fluid. When the cock is pressed, the force of fluid acting on the sealing sliding plate will not make the cock move. This forced sealing structure ensures the reliability of sealing

in addition to the main valve structure, another important structure of the plug valve is the operator

(overall structure of plug valve and schematic diagram of operator)

the function of the operator is to convert the multi rotation motion of the actuator into 90 degree rotation motion and up-down linear motion, so as to realize the rising, falling, forward and reverse rotation motion of the plug. Due to many parts involved and complex stress conditions, it is necessary to coordinate the structural parameters of relevant parts, otherwise the structure is easy to be damaged. During the development, the load characteristic requirements of the operator are obtained by analyzing the load characteristics of the main valve, and the stress analysis of the relevant parts and the finite element stress analysis of the key parts are carried out to select and optimize the structural parameters

Copyright © 2011 JIN SHI