Complete guidance for quick closing valves

What is a quick closing valve?

Quick-closing valve, also called main steam gate, is the main closing mechanism between the main steam pipeline and the turbine, which cuts off the steam inlet of the turbine in an emergency to stop the unit quickly for the purpose of protecting the unit.

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The quick closing valve is composed of the valve body and the cylinder. During operation, the valve is kept open by the quick closing oil to overcome the resistance of the spring. When the quick shutdown oil loses pressure, the piston disc and piston in the cylinder will be disconnected under the force of the spring, and the quick shutdown oil will be connected with the oil discharge port, so that the quick shutdown oil will be released instantly and the piston disc, the valve stem and the main valve disc will be pushed to the closed position.

Features of the quick closing valves

Quick closing valves are used to abruptly shut off flow in a pipeline. Quick closing valves are used in emergency situations and are designed for simple and safe operation.
The short size of the quick closing valve makes it easy to install in tight spaces. Quick closing valves can be operated remotely by manual (wire arrangement), hydraulic or pneumatic activation.
The general features of the quick-closing valve are as follows:

  • Bolt-on valve cover;
  • Male thread;
  • Availability of special decorative materials;
  • Flange connection;
  • Remote control;
  • Metal seat surface;
  • Rising handwheel;
  • Simple, safe and abrupt operation.

Structure of quick closing valves

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P.No Part Name
1 Body
2 Bonnet
3 Body Seat
4 Gasket
5 Disc
6 Stem Core
7 Sheet
8 Disc Nut
9 O-ring
10 Stem
11 Spring
12 Bonnet Nut
13 Retainer Block
14 Cylinder Bonnet
15 Release Cylinder
16 Handwheel
17 Bolt
18 Washer
19 Setscrew
20 Hex Socket Head Bolt
21 Setscrew
22 Nut
23 Washer
24 Setscrew

AII the information are only indicative data.

Operation of quick closing valves

When the quick closing valve is sailing, the oil inlet is opened, the oil outlet is closed, and the hydraulic oil is introduced from the oil inlet. Under the action of the hydraulic oil, the piston moves downward, and the bottom spring is compressed until the specified position. The quick closing valve is fully opened. At this time, the hydraulic pressure in the working chamber is balanced with the spring force at the bottom of the piston.
When the ship needs to sail in reverse, the control valve receives the command to close the quick closing valve. The control valve moves upward rapidly under the action of the top spring force for a very short time, which can be ignored. The oil outlet opens, the liquid pressure in the working chamber disappears instantly, and the piston moves upward rapidly under the action of the bottom spring force and the inertial resistance of the liquid flow. The hydraulic oil in the oil chamber is discharged from the oil outlet to the oil tank to realize the quick closing of the quick closing valve.

Operating principle of quick closing valve

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*Bonnet turned 90° from factory.

The valve is a stop valve with a remote quick closing function. A quick closing valve is in the loaded position as seen above figure. The valve ready to suddenly shut-off.

  • The quick closing operation is performed by a spring (6), pre-compressed by the hand wheel.
  • The stem (1) and the attached disc (7) are connected via the retainer block (3).
  • When the pulling back the piston rod (4), retainer block (3) and compressed spring (6) push down the disc (7) so the valve will close.

Loading the Valve for Quick Closing

*There should not be any force on the cylinder.
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Rotate the handwheel (2) clockwise until the piston rod (4) comes out of the cylinder. As a result of this process, the retainer block (3) is fixed in the upper position.

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Rotate the handwheel (2) in opening direction (anticlockwise).

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With rising of the stem, rotate the hand wheel until the thread end of the stem rests on the setting nut. At this moment, the mechanical stop is felt.

Valve closure by remote quick-closing function

The valve can be closed quickly by pulling back the piston rod (4) of the release cylinder (5) hydraulically, pneumatically or via a wire device remotely.

Closing of the valve by means of automatic release (in case of fire)

The cylinder is equipped with a melting ring. The melting ring melts at approx. 180°C or more and the spring is automatically released.

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Closing valve with handwheel (optional)

The valve can be closed by means of a handwheel. Turn the handwheel (1) clockwise. The retaining nut rests on the valve cover (2) and pushes down on the valve stem by means of the threaded connection (3). As a result, the valve closes.
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Change the direction of the release cylinder.

  • The release cylinder can be rotated.
  • loosening the two set screws (x2).
  • Rotating the release cylinder as required.
  • Tighten the set screws (x2).

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Change the direction of the valve cover.

The engine cover can be rotated.

  • Loosen the two set screws on the cylinder head a.
  • Loosen the set screw b on the nut.
  • Loosening the nut.
  • Rotating the cylinder head** as required.
  • Tighten the nut.
  • Tighten the two set screws a on the cylinder head.
  • Tighten the set screw b on the nut.
  • Check the release cylinder for proper operation.

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** Turn the cylinder head clockwise when adjusting the direction of the valve cover. It is tightened to the bottom. Then, the direction should be adjusted to return up to 1 turn.

Installation of quick closing valves.

  1. Pipes and piping systems must be installed in such a way that the tension generated by thermal (or other) expansion of the pipes does not affect the valves. In theory, this could even cause the valve to rupture, resulting in a risk of media leakage. yaang provides suitable expansion joints for this purpose.
  2. Before installation, all dirt such as sand, dust, welding residues, etc. must be removed from the pipeline. Use a filter in the appropriate part of the pipeline to protect the valve from dirt and foreign matter.
  3. Verify that the valve is suitable for the operating specifications of the medium (installation); such as maximum working pressure, maximum working temperature, corrosion and wear resistance.
  4. Verify that the distance between the flanges connecting the valve is equal to the length of the valve body.
  5. All transport and storage protection must be removed before installation.
  6. The arrow on the valve body must be in the same direction as the liquid flow.
  7. Valves should be assembled to the pipeline in the fully open position.
  8. Use gaskets between the valve flange and the butt flange. Gaskets should be suitable for operating conditions or maximum pressure/temperature ratings.
  9. The flanges of the assembled valve shall be on the same axis and the flange surfaces shall be parallel to each other.
  10. Bolts must be checked for correct size, length and material, and that all connecting flange bolt holes are used. Tighten the bolts and nuts according to the cross method shown in Figure 1 to load the pipe and valve evenly and to prevent stress on the joint. Finally, tighten the bolts to the correct torque levels recommended in Table 1. Do not overtighten.
  11. To avoid the weight and stress of the piping system on the valve, all piping systems should contain separate support mechanisms.
  12. After the installation process is complete, check the fitting for leaks. If the valve is leaking, do not use it.
  13. During installation, prevent damage to the valve’s paint.

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Figure.1 Tighten the bolts and nuts in the crossover method

Table.1 Hex Head Bolt Max.Tightening Torque

Metric M10 M12 M16 M20 M24 M27 M30 M33 M36 M39 M45 M52 M56 M64
(Grade 6.8,Steel) Torque (Nm) 37 64 158 310 535 787 1071 1455 1872 2431 3780 5850 7236 10852
(Grade 8.8,Steel) Torque (Nm) 50 87 210 412 711 1048 1422 1932 2481 3226 4992 7747 9650 14416
(Grade 70,Stainless Steel) Torque (Nm) 33 56 137 269 462 673 918 1237 1595 2057 3170 4913 6120 9130
(Grade 80,Stainless Steel) Torque (Nm) 43.5 75 183 359 617 897 1224 1648 2126 2743 4227 6550 8160 12174

Maintenance of the quick-closing valve

Yaang quick-closing valves are designed to require minimal maintenance. However, if you perform the following maintenance instructions, it will help improve the life and reliability of the valve.
The valve should be removed from the pipeline and cleaned from the media prior to maintenance.
Maintenance must be performed by qualified, trained, and skilled personnel in accordance with the maintenance instructions. Welding is not acceptable for valve maintenance.

  1. In very rare use locations, valves should be opened and closed every 3-4 months.
  2. Stem threads exposed to atmosphere should be lubricated periodically with high quality grease.
  3. When the valve is used in high temperature applications where loosening may occur, the bonnet bolt tension should be checked periodically. Although leakage through ring joints is rare, corrosion or erosion may result in ring failure. In these cases, a new seal is required.
  4. Valve O-rings should be inspected at least once a month.

Replace the gasket on the quick-close valve

Depressurize the system and remove the valve from the piping prior to removing the valve cover.
Disassembled valves will be out of warranty. If the valve is under warranty, please consult Yaang before disassembly.
Bonnet Removal

  • a) Operate the valve until it is in the fully open position.
  • b) Remove the bonnet bolt (P.No 17) using the cross method.
  • c) Lift up the bonnet assembly, being careful not to damage the valve disc.

Gasket Replacement

  • a) Discard the old gasket. (P.No 4).
  • b) Inspect the valve body gasket seat surface for wear, damage, or deterioration.
  • c) Sandpaper the gasket seating surface to remove rust, dirt, and residue from the gasket.
  • d) Clean the surface to remove all polishing residue.
  • e) Install the new gasket.

Valve Body-Cover Assembly

  • a) Inspect the bonnet bolts to ensure they are not damaged. Any damaged bolts should be replaced.
  • b) Place the entire bonnet assembly on the valve body, being careful not to damage the valve disc.
  • c) Tighten the bolts as shown in Figure 1 in a crossed method.
  • d) Test the valve as needed and put the valve back into service.

Metal-to-Metal Seals
If the valve seat inspection shows only minor defects, the seat can be renewed by grinding the valve seat with a special tool and immediate action is required.
To repair the flap seat or body seat, the valve must be removed from the pipeline using the following procedure.

  • a) Using a thicker polishing paste, rotate the tool alternately clockwise and counterclockwise by approximately 90°, pressing gently. Lift and turn the tool frequently to change its position in contact with the valve seat. Continue grinding until any defects disappear, adding polishing paste as necessary. Then clean the valve seat and repeat the process using a thinner polishing paste.
  • b) Remove the grinding tool and clean the seat carefully with a cleaning agent.
  • c) After lapping, it is recommended to check that the seat and disc surfaces are in proper contact using the blue marker. Apply the blue mark to the valve body seat and press the valve flap firmly into the valve body seat by hand. Remove the valve disc and inspect to ensure continuous contact between the sealing surfaces of the valve disc and the valve body seat.
  • d) If this contact is not uniform, repeat steps a, b, and c until good contact is obtained. If the valve disc defect is large, repair may be attempted by metal cutting the valve disc sealing surface on a lathe. After metal cutting, grind as described above.

How do you close a quick closing valve?

To close a quick closing valve:

  • Shut off the valve. Turn it to the closed position.
  • If you can’t shut off the valve, turn it to the closed position and then use a wrench to tighten it. Do not use a hammer or other tool to tighten the valve; this could damage your equipment and cause injuries.

What is the purpose of quick closing valves?

Quick closing valves are used to stop the flow of liquids and gasses in pipes. They are also known as quick opening valves, as they can be opened and closed quickly—most in less than 10 seconds. These valves are constructed from metal, plastic or rubber and come in a variety of sizes and styles, depending on the industry they’re used in and the application that they fulfill.

  • 1. It is connected with the combustible gas leakage monitoring instrument. When the instrument detects the combustible gas leakage, it automatically and quickly closes the main gas supply valve, cuts off the gas supply, and timely stops the occurrence of malignant accidents.
  • 2. It is connected with the limit temperature and pressure safety controller of the thermal equipment. When the temperature and pressure at the detection point in the equipment exceed the set limit value, it will automatically and quickly close the gas supply valve and stop the fuel supply.
  • 3. It is connected with the central fire alarm system of high-rise buildings. When a fire alarm occurs in the building, the gas supply in the building will be automatically cut off to prevent gas explosion.
  • 4. It is set in the gas supply pipe network of the city or factory, and can be centrally controlled in the central control room. Remote control can quickly close the pipeline gas supply at the accident site.
  • 5. The quick closing valve is the main closing mechanism between the steam pipe network and the small turbine. When an accident occurs in operation, it can cut off the steam entering the small turbine in the shortest time.

How To Choose Quick Closing Valves?

To choose a quick closing valve for your application, consider the following factors:
The type of fluid or substance that will pass through the valve.
There are many different types of fluids and substances that may pass through a quick closing valve, including water, gas and oil. As you search for your ideal quick closing valve, it’s important to determine what kind of substance will be passing through it so that you can find the best option for your specific application. For example, if you’re looking for a high-quality fluid transfer system to use with water or other fluids that need to be quickly shut off when pressure is lost in pipes or hoses (such as those located underground), then check out our selection of plug valves. If instead you’re searching for an air pressure regulator device suitable for use with compressed air cylinders on construction sites around town—or even just at home—we recommend checking out our extensive inventory of pressure regulators instead!
Consider the application where the valve will be used.
It is important to consider the application where the valve will be used. You should check the operating pressure of the valve and whether or not it is made for a particular type of fluid passing through it. There are many different applications where quick closing valves can be used, such as:

  • Oil and gas exploration;
  • Chemical process industries (CPI);
  • Water treatment plants.

Consider the type of fluid that will pass through the valve.
To determine the type of valve you need, you’ll need to consider the type of fluid that will pass through it. If it’s dirty and corrosive, then a valve with corrosion resistance and high-temperature capabilities is probably best. A clean or noncorrosive fluid can be contained by more basic valves.
Consider what desirable features you need for a quick closing valve for your specific application.
Once you’ve identified the type of closure you need, it’s time to select a valve. The selection process is complicated by the fact that there are so many different types of valves available for different applications.
Consider what desirable features you need for a quick closing valve for your specific application: If you’re working with highly corrosive fluids like oils or acids, then stainless steel bodies will be more resistant than carbon steel ones. You’ll also want to make sure that your valves have high flow capacities and good pressure ratings—and they should be able to handle temperatures up to 500 degrees Fahrenheit (260 degrees Celsius).
However, if these aren’t necessary requirements for your application—or if they’re just not possible due to cost constraints—then consider choosing among different types of valves based on the type of closure you need:
Choose among different types of valves based on the type of closure you need.
When choosing a valve, it is important to consider the type of closure you need. There are three main types of closures:

  • Closing under pressure – These valves use closing springs or other pressure-supported techniques to maintain closure. They are best suited for situations where there is a high risk of backflow or contamination from the outside environment into your system.
  • Closing without pressure – These valves rely on gravity and/or friction to prevent leakage under normal conditions, but they can still be closed at any time by manually applying additional force. They may be useful if you want to control flow rates or monitor how much liquid has passed through your system, but do not want the added complexity associated with using closing springs.
  • Self-closing – This type of valve does not require any external mechanism in order to maintain closure; therefore it is ideal for applications where there could be an accidental loss of power supply (such as during a storm).

Check to make sure that the quick closing valve you choose can handle the operating pressure.
There are three types of quick closing valves, and each type has a different pressure rating. For example, the 300 series quick closing valves are rated up to 15 psi while the 600 series is rated up to 40 psi. If you have low-pressure applications (say, under 10 psi), then you’ll want to use a 300 series valve because it can handle the lower pressures. You’ll also want to check with your supplier or manufacturer about their maximum operating pressure ratings for fluid handling applications so that you don’t exceed that limit when selecting a specific type of quick closing valve for your application.

How to choose the manufacturer of quick closing valves?

If you want to choose a manufacturer who can provide quick closing valves at an affordable price then you need to know the following things:

To begin with, you need to make sure that the company can provide you different types of valves.

There are different types of valves available in the market at present and it is important to find out whether the manufacturer you have chosen has a wide range of options for this particular equipment or not. You should also look for companies that can provide you with valves in different sizes and shapes so that your requirements can be fulfilled well.

You should also check if the manufacturer provides quick closing valves in different materials as this will help you get the right product according to your needs. For example, if there is any requirement for a high-pressure system then stainless steel material may be used while low pressure systems require brass made products because they are more cost-effective than stainless steel ones

You should also check if the valves are available in the market in different sizes and shapes.

The size of quick closing valves varies from 2 to 20 inches, with special features like stainless steel construction, explosion proof design and pressure rating up to 6000 PSI.

The valves can be used for a number of applications such as production lines, oil wells, power plants and trains among others. They can also be customized according to your requirements regarding materials used, pressures handled etc.

The next thing that you need to consider is the reputation of the manufacturer.

When you are choosing a manufacturer of quick closing valves, the next thing that you need to consider is the reputation of the manufacturer. A good manufacturer has a great reputation and can be easily contacted by their customers. They also offer warranties on their products and have a good track record with previous customers.

The best way for you as a consumer to find out whether or not an individual company has a good reputation is to read reviews from other people who have already bought from them before. You can also reach out directly via email or phone call if they have one listed publicly available information about how they operate in terms of communication with clients so that way there aren’t any surprises down the road when something goes wrong with your particular order (which will hopefully never happen).

The first thing that you should do is to determine the budget that you have for buying the valves. You should make sure that you have enough money to buy the valves. If you don’t have enough money, save more until you can afford it.

The next thing that you have to do is to determine the budget that you have for buying the valves. The main objective of determining your budget is so that at a later stage, when it comes time for purchasing these items, there will be no problems with regards financial constraints; therefore, having established a concept of your financial ability in advance allows one not only save themselves from being caught off-guard but also prevents them from incurring unnecessary costs due lack knowledge regarding available options available within their current range of affordability

You should also ask questions about how they manufacture their valves so that you can be assured that they are made from good quality materials.

Questions you should ask include:

  • What materials are used in making the valve?

  • What type of testing procedures do they use to ensure the quality of their valves?

  • What is their warranty policy?

You should also inquire about their shipping policies and how much time it takes for them to deliver these valves.
You can get a quote from the manufacturer and ask them for a sample before you place an order.

The last tip is to find a company who offers warranty services for these products.

The warranty will protect you from any defects in manufacturing and ensure that the product works as advertised when you receive it. A good warranty program gives you peace of mind in knowing that if something does go wrong with your quick closing valve, you’ll be able to get it fixed quickly and efficiently without losing any money or having to buy new parts yourself.

Warranty programs can vary widely between manufacturers and sellers, so make sure to check out what kind of coverage the company offers before deciding which brand is right for you. Some manufacturers offer only 1-year warranties on their products; others extend their warranties up to 3 years from date of purchase or installation (whichever comes first).

Getting quick closing valves can be a daunting task but it will be worth it in the end.

If you want to get the most out of your quick closing valve, here are some tips:

  • Make sure to get a good quality product. This is especially important if you’re looking for a warranty because it will protect you from any defects that might occur on the part of the manufacturer or distributor.

  • Get a warranty for the valves. A good way of doing this is by checking how long they have been in operation and how many people have purchased them before making your decision about which one works best for what tasks need doing around home/office building site etcetera (sic)

  • Make sure they’re sized appropriately too since having mismatched size between two different components may result in leaks which could lead into costly repairs later down line or even worse – flooding!


It’s important to find the right manufacturer for quick closing valves. If you want to get the best quality products at the best price, then make sure that you are dealing with a reputable company. You can choose from many different manufacturers in China or anywhere else in the world so make sure that you take your time when choosing one because once they get your order, it will be difficult to change things around later on down the road.

Source: China Quick Closing Qalves Manufacturer – Yaang Pipe Industry Co., Limited (

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Stainless Steel Valves, Stainless Steel Flanges, Stainless Steel Pipe Fittings, and Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels, and other industries.)

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