Low temperature thread Globe valve
Model: DJ11F-16P
Specification: DN25
1、 Selection of stop valve:
1. Stop valves should be selected for pipelines or devices with high-temperature and high-pressure media. Such as thermal power plants, nuclear power plants, high temperature and high pressure pipelines of petrochemical systems.
2. On the pipeline where the flow resistance is not strictly required. That is, where the pressure loss is not considered much.
3. Small valve Needle valve, instrument valve, sampling valve Manometer Valves, etc.
4. There is flow regulation or pressure regulation, but the requirement for regulation accuracy is not high, and the pipeline diameter is relatively small. For example, the pipeline with nominal diameter ≤ 50mm should be selected.
5. High pressure angle stop valve or high pressure angle throttle valve with nominal pressure PN160 and nominal pressure 16MPa or PN320 and nominal pressure 32MPa should be selected for small and large chemical fertilizers in synthetic industrial production.
6. In the desilication workshop of alumina Bayer process production and the pipeline prone to coking, it is easy to select the DC stop valve or DC throttle valve with separate valve body, removable valve seat and cemented carbide sealing pair.
7. For water supply and heat supply projects in urban construction, stop valve, balance valve or Plunger valve , such as the pipeline with nominal diameter less than 150mm. The obvious advantage is that during the opening and closing process, due to the friction ratio between the valve disc and the sealing surface of the valve body Gate valve Small, therefore wear-resistant. The opening height is generally only 1/4 of the diameter of the valve seat channel, so it is much smaller than the gate valve. Generally, there is only one sealing surface on the valve body and disc, so the manufacturing process is better and it is easy to maintain. Nominal pressure or pressure class: PN1.0-16.0MPa, ANSI CLASS 150-900, JIS10-20K Nominal diameter or caliber: DN10 ～ 500, NPS 1/2 ～ 36 "Connection mode: flange, butt welding, thread, etc. Applicable temperature: - 196 ℃ ～ 700 ℃ Drive mode: manual, bevel gear drive, pneumatic, electric, hydraulic, pneumatic hydraulic, electro-hydraulic valve body material: WCB ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. Different materials can be used for water, steam, oil, nitric acid, acetic acid, oxidizing media, urea and other media.
2、 Principle of stop valve
The stem axis of the low-temperature stop valve is perpendicular to the sealing surface of the valve seat. The valve rod has a relatively short opening or closing stroke and a very reliable cutting action, making this valve very suitable for cutting off, adjusting and throttling as a medium.
Once the cryogenic stop valve is in the open state, there is no contact between its valve seat and the sealing surface of the valve disc, so the mechanical wear of its sealing surface is relatively small. Since the valve seat and disc of most stop valves are relatively easy to repair or replace the sealing elements, it is not necessary to remove the entire valve from the pipeline, which is very suitable for the occasion where the valve and pipeline are welded together. The flow direction of the medium has changed when passing through this type of valve, so the flow resistance of the stop valve is higher than that of other valves.
3、 Features of stop valve:
1. The structure is simpler than the gate valve, and the manufacturing and maintenance are more convenient.
2. The sealing surface is not easy to wear and scratch, and has good sealing performance. There is no relative sliding between the valve disc and the valve body sealing surface when opening and closing, so the wear and scratch are not serious, the sealing performance is good, and the service life is long.
3. When opening and closing, the valve disc travel is small, so the height of the stop valve is smaller than that of the gate valve, but the structural length is longer than that of the gate valve.
4. The opening and closing torque is large, the opening and closing is laborious, and the opening and closing time is long.
5. The fluid resistance is large, because the medium channel in the valve body is more tortuous, the fluid resistance is large, and the power consumption is large.
6. When the nominal pressure of the medium flow direction PN ≤ 16MPa, it is generally downstream, and the medium flows upward from the lower direction of the valve disc; When the nominal pressure PN ≥ 20MPa, the reverse flow is generally adopted, and the medium flows down from the upper direction of the valve disc to increase the sealing element energy. When in use, the medium of the stop valve can only flow in one direction and cannot change the flow direction.
7. The valve disc is often eroded when fully opened.
4、 Advantages of stop valve:
1. Simple structure, easy to manufacture and maintain.
2. Small working stroke, short opening and closing time.
3. Good sealing performance, low friction between sealing surfaces, long service life.
The products of Shanghai Weidie Valve Co., Ltd. include: wafer butterfly valve, worm wheel butterfly valve, flange butterfly valve, electric butterfly valve, pneumatic butterfly valve, ball valve, gate valve, stop valve, check valve, filter, drain valve, plunger valve and many other types of valves
