how safety valve works made in china

As soon as mankind was able to boil water to create steam, the necessity of the safety device became evident. As long as 2000 years ago, the Chinese were using cauldrons with hinged lids to allow (relatively) safer production of steam. At the beginning of the 14th century, chemists used conical plugs and later, compressed springs to act as safety devices on pressurised vessels.

Early in the 19th century, boiler explosions on ships and locomotives frequently resulted from faulty safety devices, which led to the development of the first safety relief valves.

In 1848, Charles Retchie invented the accumulation chamber, which increases the compression surface within the safety valve allowing it to open rapidly within a narrow overpressure margin.

Today, most steam users are compelled by local health and safety regulations to ensure that their plant and processes incorporate safety devices and precautions, which ensure that dangerous conditions are prevented.

The principle type of device used to prevent overpressure in plant is the safety or safety relief valve. The safety valve operates by releasing a volume of fluid from within the plant when a predetermined maximum pressure is reached, thereby reducing the excess pressure in a safe manner. As the safety valve may be the only remaining device to prevent catastrophic failure under overpressure conditions, it is important that any such device is capable of operating at all times and under all possible conditions.

Safety valves should be installed wherever the maximum allowable working pressure (MAWP) of a system or pressure-containing vessel is likely to be exceeded. In steam systems, safety valves are typically used for boiler overpressure protection and other applications such as downstream of pressure reducing controls. Although their primary role is for safety, safety valves are also used in process operations to prevent product damage due to excess pressure. Pressure excess can be generated in a number of different situations, including:

The terms ‘safety valve’ and ‘safety relief valve’ are generic terms to describe many varieties of pressure relief devices that are designed to prevent excessive internal fluid pressure build-up. A wide range of different valves is available for many different applications and performance criteria.

In most national standards, specific definitions are given for the terms associated with safety and safety relief valves. There are several notable differences between the terminology used in the USA and Europe. One of the most important differences is that a valve referred to as a ‘safety valve’ in Europe is referred to as a ‘safety relief valve’ or ‘pressure relief valve’ in the USA. In addition, the term ‘safety valve’ in the USA generally refers specifically to the full-lift type of safety valve used in Europe.

Pressure relief valve- A spring-loaded pressure relief valve which is designed to open to relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored. It is characterised by a rapid-opening ‘pop’ action or by opening in a manner generally proportional to the increase in pressure over the opening pressure. It may be used for either compressible or incompressible fluids, depending on design, adjustment, or application.

Safety valves are primarily used with compressible gases and in particular for steam and air services. However, they can also be used for process type applications where they may be needed to protect the plant or to prevent spoilage of the product being processed.

Relief valve - A pressure relief device actuated by inlet static pressure having a gradual lift generally proportional to the increase in pressure over opening pressure.

Relief valves are commonly used in liquid systems, especially for lower capacities and thermal expansion duty. They can also be used on pumped systems as pressure overspill devices.

Safety relief valve - A pressure relief valve characterised by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on the application, and which may be used either for liquid or compressible fluid.

In general, the safety relief valve will perform as a safety valve when used in a compressible gas system, but it will open in proportion to the overpressure when used in liquid systems, as would a relief valve.

Safety valve- A valve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of the fluid so as to prevent a predetermined safe pressure being exceeded, and which is designed to re-close and prevent further flow of fluid after normal pressure conditions of service have been restored.

Because of different of drive source, SSV can dividedinto Hydraulic safety valve and pneumatic valve ; With thermal and high voltage explosion-proof device ; Actuators and prepare two parts of the valve, standard interface, easy replacement and maintenance .

This valve is used for power plant boilers, pressure containers, pressure and temperature reducing device and other facilities. It serves to prevent the pressure exceeding the highest allowable pres-sure value and ensure the safety of the device when working.

（1）The pressure of the disc is balanced through the lever and heavy hammer and the valve is ensured seal by moving the for ton of heavy hammer and changing the weight of heavy hammer to reach the required set pressure.

（3）At the top of valve is equipped an electromagnet to open and another to close the valve. The actions of the mechanism and the electric appliance are separate and will not affect each other.

（2）Impulse safety valve shall be installed vertically and the lever shall be kept level. The clearance from the lever to both sides of guide fork shall be even.

（4）A long distance between the leading pipe of the impulse safety valve and the inlet pipe of the main safety valve shall be kept. And the distance between the electric contact pressure meter and the inlet pipe of the main safety valve shall be no less than 5 times of the diameter of the inlet pipe, for feat that the validity of the mater and the impulse safety valve may be affected by the steam releasing process of the main safety valve.

This valve is used for power plant boilers, pressure containers, pressure and temperature reducing device and other facilities. It serves to present the pressure exceeding the highest allowable pres-sure value and ensure the safety of the device when working.

1,When the medium pressure rises to the set pressure, the in-pulse safety valve opens, and the medium in the impulse pipe enters into the piston chamber of the main safety valve from impulse pipe, forcing the piston to descend, and then the valve automatically open-s; when the impulse safety valve closes, the disc will slash automatically close.

2,The main safety valve shall be fastened upon the gallows, which sustains the back-seat force produced in the steam discharging process of the main safety valve.

3,The exhaust pipe shall contain a special gallows to prevent the force of its weight directly applying on the main safety valve. The connecting Lange At the lowest point of the exhaust pipe, water drainage shall be taken into consideration to avoid producing water hammer while discharging set between the main safety valve and exhaust pipe shall eliminate any extra stress.

A safety valve protects the system and equipment from overpressure. Overpressure develops when the pressure exceeds the system’s maximum allowable working pressure (MWAP) or the pressure under which it has been designed. Safety valves have a short opening time to discharge gases or liquids immediately. A safety valve opens when a certain pressure is reached; it opens partially at first to eliminate undesirable pressure from the system as rapidly as possible.

Safety valves are utilized to stop pressure rises that might cause malfunctions, fire risks, or explosions. Safety valves are utilized when electrical or pneumatic safety systems malfunction since they only have mechanical components. The system’s media fully activates a safety valve, keeping it operational in the case of a power failure.

China is one of the countries that can meet many conditions as well as products in the world. We can feel through the fact that now our country has to 85% of the sources of goods imported from this country. Because the sources of goods come from China, there are always certain advantages. And ball valve is no exception, so when you buy Chinese ball valve there are the following advantages.

For large sized valves, you can ask the company to order with the factory. The import time to Vietnam is only from 25 to 30 days. Much faster than brands from the EU or G7.

Can say, ball valvesChina has many different product lines. And one of the points to distinguish the type, the material is also one of the indispensable methods.

Leading the product is still Chinese stainless steel ball valve, why do I say that. The reason comes from the fact that stainless steel valves are always imported in large quantities, and the density of user selection is much larger.

In stainless steel ball valve, it is divided into 3 smaller products, which are 201, 304, 316 stainless steel valves. In which 201 stainless steel ball valves will have the cheapest price, the highest has 316 stainless steel valves.

Told you now to ask the question, what valve is suitable for high temperature systems. More specifically, the steam system can be taken as an example.

The answer is that you can use steel ball valves, instead of other ball valves. Because the temperature is too high, if you use a kettle made from plastic or cast iron and stainless steel. This will greatly reduce the valve"s durability.

For steel ball valves, the smallest size is DN32, and only one type of flange connection without thread is used. Flanges are manufactured according to BS standards, if you want to use JIS or ANSI standards, they are not available.

Chinese ball valves are made from copper material, and are quite small in size. Simply from dn15 to dn50. For copper, the main use is still clean water, and some basic steam systems do not exceed 150 degrees Celsius.

Compared to the two valve lines that I have just shared above, the Chinese bronze ball valve is much cheaper. Therefore, chemical systems should not use copper valves. You must switch to using plastic or stainless steel valves.

The final product today is a line of ball valves made from plastic. If stainless steel valves have 3 smaller valve lines from materials, then plastic valves are not inferior at all. Materials used to manufacture plastic ball valves include the following materials: PVC, UPVC, CPVC, PPH.

Not a product that uses all of the above materials, but each type of valve will use a material. The highest is still the valve made from PPH plastic material.

To understand what parts the Chinese ball valve is composed of, you only need to pay attention to the following main parts. And these parts apply to every other line of ball valves, differing only slightly in the material part.

Hand lever: For the lever is an indispensable part for the ball valve, if you need it, you can replace the lever with electric or gas. In this case, these controllers may come from a third party that our company imports, which is not from China.

Ball valve: Butterfly valve gate valve has vane, but for Chinese ball valve, there is a ball valve part. This is also the reason why the name ball valve was born. Machined in a circular shape, so that the friction is minimal. Both ensure a tight seal to the body and the opening process is smooth and gentle.

Valve shaft: The shaft is attached to the device, the top allows the lever to be attached. So when you turn the lever, the valve shaft and the ball below also rotate. Shafts are always made from stainless steel, only steel ball valves are made of steel.

What we need to do to change the opening and closing state for the valve, just apply force to the lever and pull in the right direction. That the manufacturer has proposed, to know how to open and close you can look at the arrow on the lever.

When pulling the lever clockwise and parallel to the flow, the valve will open. If you want to close the valve, you need to pull the lever back to finish.

For Chinese ball valves, in choosing a valve you also need to pay attention to some of the following notes. This helps you to limit unnecessary mistakes, the second one helps you get the most suitable product. In simpler terms, it is to limit the risk when shopping.

The first is to see if the investor has specified any products or not. If specifying certain products, which are not valves from China. Should reconsider buying and choosing.

Pressure relief valves (safety relief valves) are designed to open at a preset pressure and discharge fluid until pressure drops to acceptable levels. The development of the safety relief valve has an interesting history.

Denis Papin is credited by many sources as the originator of the first pressure relief valve (circa 1679) to prevent overpressure of his steam powered “digester”. His pressure relief design consisted of a weight suspended on a lever arm. When the force of the steam pressure acting on the valve exceeded the force of the weight acting through the lever arm the valve opened. Designs requiring a higher relief pressure setting required a longer lever arm and/or larger weights. This simple system worked however more space was needed and it coud be easily tampered with leading to a possible overpressure and explosion. Another disadvantage was premature opening of the valve if the device was subjected to bouncing movement.

Direct-acting deadweight pressure relief valves: Later to avoid the disadvantages of the lever arrangement, direct-acting deadweight pressure relief valves were installed on early steam locomotives. In this design, weights were applied directly to the top of the valve mechanism. To keep the size of the weights in a reasonable range, the valve size was often undersized resulting in a smaller vent opening than required. Often an explosion would occur as the steam pressure rose faster than the vent could release excess pressure. Bouncing movements also prematurely released pressure.

Direct acting spring valves: Timothy Hackworth is believed to be the first to use direct acting spring valves (circa 1828) on his locomotive engine called the Royal George. Timothy utilized an accordion arrangement of leaf springs, which would later be replaced with coil springs, to apply force to the valve. The spring force could be fine tuned by adjusting the nuts retaining the leaf springs.

Refinements to the direct acting spring relief valve design continued in subsequent years in response to the widespread use of steam boilers to provide heat and to power locomotives, river boats, and pumps. Steam boilers are less common today but the safety relief valve continues to be a critical component, in systems with pressure vessels, to protect against damage or catastrophic failure.

Each application has its own unique requirements but before we get into the selection process, let’s have a look at the operating principles of a typical direct acting pressure relief valve.

In operation, the pressure relief valve remains normally closed until pressures upstream reaches the desired set pressure. The valve will crack open when the set pressure is reached, and continue to open further, allowing more flow as over pressure increases. When upstream pressure falls a few psi below the set pressure, the valve will close again.

Most commonly, pressure relief valves employ a spring loaded “poppet” valve as a valve element. The poppet includes an elastomeric seal or, in some high pressure designs a thermoplastic seal, which is configured to make a seal on a valve seat. In operation, the spring and upstream pressure apply opposing forces on the valve. When the force of the upstream pressure exerts a greater force than the spring force, then the poppet moves away from the valve seat which allows fluid to pass through the outlet port. As the upstream pressure drops below the set point the valve then closes.

Piston style designs are often used when higher relief pressures are required, when ruggedness is a concern or when the relief pressure does not have to be held to a tight tolerance. Piston designs tend to be more sluggish, compared to diaphragm designs due to friction from the piston seal. In low pressure applications, or when high accuracy is required, the diaphragm style is preferred. Diaphragm relief valves employ a thin disc shaped element which is used to sense pressure changes. They are usually made of an elastomer, however, thin convoluted metal is used in special applications. Diaphragms essentially eliminate the friction inherent with piston style designs. Additionally, for a particular relief valve size, it is often possible to provide a greater sensing area with a diaphragm design than would be feasible with a piston style design.

The reference force element is usually a mechanical spring. This spring exerts a force on the sensing element and acts to close the valve. Many pressure relief valves are designed with an adjustment which allows the user to adjust the relief pressure set-point by changing the force exerted by the reference spring.

What is the maximum flow rate that the application requires? How much does the flow rate vary? Porting configuration and effective orifices are also important considerations.

The chemical properties of the fluid should be considered before determining the best materials for your application. Each fluid will have its own unique characteristics so care must be taken to select the appropriate body and seal materials that will come in contact with the fluid. The parts of the pressure relief valve in contact with the fluid are known as the “wetted” components. If the fluid is flammable or hazardous in nature the pressure relief valve must be capable of discharging it safely.

In many high technology applications space is limited and weight is a factor. Some manufactures specialize in miniature components and should be consulted. Material selection, particularly the relief valve body components, will impact weight. Also carefully consider the port (thread) sizes, adjustment styles, and mounting options as these will influence size and weight.

In many high technology applications space is limited and weight is a factor. Some manufactures specialize in miniature components and should be consulted. Material selection, particularly the relief valve body components, will impact weight. Also carefully consider the port (thread) sizes, adjustment styles, and mounting options as these will influence size and weight.

A wide range of materials are available to handle various fluids and operating environments. Common pressure relief valve component materials include brass, plastic, and aluminum. Various grades of stainless steel (such as 303, 304, and 316) are available too. Springs used inside the relief valve are typically made of music wire (carbon steel) or stainless steel.

The materials selected for the pressure relief valve not only need to be compatible with the fluid but also must be able to function properly at the expected operating temperature. The primary concern is whether or not the elastomer chosen will function properly throughout the expected temperature range. Additionally, the operating temperature may affect flow capacity and/or the spring rate in extreme applications.

Beswick Engineering manufactures four styles of pressure relief valves to best suit your application. The RVD and RVD8 are diaphragm based pressure relief valves which are suited to lower relief pressures. The RV2 and BPR valves are piston based designs.

Solenoid directional valves and cartridges with inductive sensors to monitor the spool/poppet position, certified to Machine Directive 2006/42/EC. Pressure relief valves certified to PED 2014/68/EU.

We always get the job done to be a tangible staff to ensure that we can easily offer you the best high-quality and the greatest value for Wedge Gate Valve, Gate Valve, Double Flanged Dual Plate Check Valve.Faced with economic globalization, we are determined to become a leader in the Safety Relief Valve industry and surpass ourselves. We sincerely hope to cooperate with you, share success together, and forge ahead firmly to a more brilliant future. We have a group of highly educated, skilled and technically proficient service team and strict quality management system. We are equipped with professional R&D team, design team and engineering team to provide comprehensive after-sales guarantee for our customers. Our company has complete equipment, complete and scientific quality management system. We adhere to the quality policy of people-oriented, integrity and customer satisfaction. We will take a serious and responsible attitude towards the friendly cooperation with foreign customers and peers. Innovation is the soul of improving the competitiveness of an enterprise. This includes product innovation and management innovation. Product innovation can continuously improve the value content and competitiveness of products, and management innovation can ensure that enterprises are more efficient.

We are very pleased to be able to cooperate with you, the products received are no different from the promotional pictures, which shows your sincerity as a manufacturer, and we hope to maintain a

We are adhering to the concept of ethics, honesty, pursuit of excellence, and win-win cooperation, and we are willing to work together with colleagues from all walks of life to write a brilliant chapter in the field of Globe Valve, Pneumatic Air Control Valve, Fully Lugged Butterfly Valve! We"re well-known as one of the leading Safety Relief Valve manufacturers and suppliers in China. Please feel free to wholesale high quality Safety Relief Valve for sale here from our factory. Good service and punctual delivery are available.

Since the early 1940s, the Farris Engineering unit of Curtiss-Wright Flow Control has designed and produced a wide range of spring-loaded and pilot-operated pressure relief valves. Used as safety devices, Farris pressure relief safety valves prevent over pressurization of vessels, pipelines, and equipment. Farris manufacturing is a company recognized as a leader in the hydrocarbon processing, refinery, petrochemical, natural gas production/transmission, pharmaceutical, and general processing industries worldwide. Their safety valves and other PRV hardware can be found across the globe – from the U.S. to the U.K. and S. America to China.

A pioneer in the field, the Farris Engineering company created many safety pressure relief products that remain industry standards. Integrating its core hardware technology with the information age, Farris developed computer software to assist customers in the sizing and selection of safety valves for all manner of piping and equipment. A recent reorganization of manufacturing plants and processes maximized production effectiveness to position the business unit at the forefront of the industry, with service and delivery second to none. If you are looking for an effective, high-quality safety valve and engineering expertise for any and all pressure relief management questions – look to the safety valve companies Farris Engineering and North American Machine Works.