Aira 4matic Global Valve Automation Private Limited

Introduction to Pressure Relief valves
Pressure Relief Valves

A pressure Relief Valve is a safety device designed to protect a pressurized vessel or system during an overpressure event.
An overpressure event refers to any condition which would cause pressure in a vessel or system to increase beyond the specified design pressure or maximum allowable working pressure (MAWP).

The primary purpose of a pressure Relief Valve is protection of life and property by venting fluid from an overpressurized vessel.

Many electronic, pneumatic and hydraulic systems exist today to control fluid system variables, such as pressure, temperature and flow. Each of these systems requires a power source of some type, such as electricity or compressed air in order to operate. A pressure Relief Valve must be capable of operating at all times, especially during a period of power failure when system controls are nonfunctional. The sole source of power for the pressure Relief Valve, therefore, is the process fluid.

Once a condition occurs that causes the pressure in a system or vessel to increase to a dangerous level, the pressure Relief Valve may be the only device remaining to prevent a catastrophic failure. Since reliability is directly related to the complexity of the device, it is important that the design of the pressure Relief Valve be as simple as possible.

The pressure Relief Valve must open at a predetermined set pressure, flow a rated capacity at a specified overpressure, and close when the system pressure has returned to a safe level. Pressure Relief Valves must be designed with materials compatible with many process fluids from simple air and water to the most corrosive media. They must also be designed to operate in a consistently smooth and stable manner on a variety of fluids and fluid phases.
Spring Loaded Pressure Relief Valve

The basic spring loaded pressure Relief Valve has been developed to meet the need for a simple, reliable, system actuated device to provide overpressure protection.

The image on the right shows the construction of a spring loaded pressure Relief Valve.

The Valve consists of a Valve inlet or nozzle mounted on the pressurized system, a disc held against the nozzle to prevent flow under normal system operating conditions, a spring to hold the disc closed, and a body/Bonnet to contain the operating elements. The spring load is adjustable to vary the pressure at which the Valve will open.

When a pressure Relief Valve begins to lift, the spring force increases. Thus system pressure must increase if lift is to continue. For this reason pressure Relief Valves are allowed an overpressure allowance to reach full lift. This allowable overpressure is generally 10% for Valves on unfired systems. This margin is relatively small and some means must be provided to assist in the lift effort.

Most pressure Relief Valves, therefore, have a secondary control chamber or huddling chamber to enhance lift. As the disc begins to lift, fluid enters the control chamber exposing a larger area of the disc to system pressure.

This causes an incremental change in force which overcompensates for the increase in spring force and causes the Valve to open at a rapid rate. At the same time, the direction of the fluid flow is reversed and the momentum effect resulting from the change in flow direction further enhances lift. These effects combine to allow the Valve to achieve maximum lift and maximum flow within the allowable overpressure limits. Because of the larger disc area exposed to system pressure after the Valve achieves lift, the Valve will not close until system pressure has been reduced to some level below the set pressure. The design of the control chamber determines where the closing point will occur.

Low Pressure Steam Boiler Safety Valves
ASME Section IV Set pressures from 5 to 15 psig. Sizes 2 , 2-1/2 and 3 . Applications: This an ASME Section IV high capacity steam safety valve for use with medium and large size commercial and industrial heating boilers.
• One piece body, all ss construction
• Rust proofed steel spring
• Chrome plated seat, PTFE coated disc
• PTFE coated EPDM O-ring for positive seal
• Side tapping for gauge connection
• Valves are capacity certified by the National Board at 15 psig only, in accordance with ASME Boiler and Pressure Vessel Code Section IV
• Test gag available to prevent the valve from opening during hydrostatic testing of the boiler.

Capacities and dimensions
    Compliance with API 526
    Diverse selection of high-alloy materials available as standard
    Longer lifetime due to hardened discs, partly stellited seats and integrated shielding of the optional bellows
    Single trim: Identical internal parts for S/G/L for cost-effective maintenance
    4Matic Nanotightness: Exceeds the tightness requirements of API 527 by 50%

 Industries
    Chemical
    Oil & Gas
    Petrochemical
    Technical Gases
    General industries


 Safety and reliability in a diverse industry
There are many different types of plants in the chemical industry, which forms the backbone of our industrialized world. Plants for polymers, fertilizers, soaps or cleaning agents; production in bulk, batches or continuous; different units for the process medium, steam, cooling or heating are increasing the requirements in quantity and diversity.
Hence, a partner is needed who provides the required wide product range, technical expertise and the ability to integrate into the growing supply chains. 4Matic is the supplier of safety valves covering all applications and regulations. The product group High Performance is the standard safety valve for the chemical industry. The product group Critical Service is designed for highly corrosive media such as chlorine. Modulate Action safety valves minimize media loss. In addition, 4Matic increases the availability of your plant with the change-over valves from the Best Availability product group.
No matter what the requirements are: from overpressure protection during thermal expansion in pipelines to process steam or toxic and corrosive media. With the 4Matic Alloy Concept, aggressive media can also be protected.

Media losses must be minimized in order to improve efficiency or protect life and the environment. Special tightness requirements such as PAS 1085 are met with 4Matic Nanotightness. The pilot operated safety valves or the use of the supplementary loadind system even exceed these requirements.
Kyrgyzstan, Nepal, Bhutan, Laos, Myanmar, Thailand, Vietnam, Spratley, Brunei, Malaysia, Combodia, Singapore, Indonesia, Est Timor, Australia, Niue, Samoa, Wallis and futuna, Fiji, New Caledonia, Samoa, Tokelau, Kiribati, Tuvalu, Solomon, Nauru, Papua New Gunea, Micronesia, Palau, Micronesia, Guam, Marshall, Northern Maniana, Philippines, Taiwan, South Korea, North Korea, Japan, Sri Lanka, Maldives, Afghanistan, Uzbekistan, Tajikistan, Kazakhstan, Mongolia, Russia.
Indonesia, Malaysia, South Africa, Ghana, Nigeria, Senegal, Egypt, Turkey, Benin, Burkina Faso, Cape Verde, Cote d'Ivoire (Ivory Coast), Gambiav, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Saint Helena, Sierra Leone, Sao Tome and Principe
Togo, Algeria, Libya, Morocco, Tunisia, South Sudan, Sudan, Western Sahara (Territory), Jordan, Bahrain, Iraq, Iran, Qatar, Kuwait, Syria, Israel, Cyprus, Lebanon, Canada

The application can be seen in the oil and gas, power generation, chemical and petrochemical industries. The pressure capacities of the different types such as the CF8M Stainless Steel Angle Needle Valve can range up to 10000psi or 689 bars. The operating temperatures of the valves range up to 648 degrees Celsius. The applications can also be seen in meters and instruments for precision measurements. The CF8 Stainless Steel Flanged Needle Valves can range in sizes. The end connection can range from 1/8 inches to ½ inches. The end connections for the different types such as the 1/4 Inch ASTM A351 CF8M 316 Needle Control Valve can range as duolok, unilok, griplok, tube fitting or trufit pipe fitting types. As a leading supplier, we supply different types such as the A351 CF8 304 Water Flow Control Needle Valve and others. There are straight and angle valves. Please feel free to contact us for more information and pricing of the different types such as the High Temperature Needle Valve and others.

Pop type safety valves are meant for use on steam, air, gas or vapour service (i.e. for compressible fluids). The maximum set pressure for which these valves can be supplied is 250 psig (17.24 bar). Recommended maximum working temperature is 435°F (225°C)