Control and safety valves

Control and safety valves are important in safely and optimally using fluids in cooling, heating, and industrial facilities. The following presents information on models and brands, reviews, how to choose, and wholesale purchase prices of all types of control and safety valves.

Review and selection guide for control and safety valves

If you want to use a safety and control valve and the fluid pressure differences, and you do not know what type of control and safety valve, type of connection, brand, price, and specifications, continue this. Join us to answer all your questions about the purchase price, technical specifications and the best types of control and safety valves you need!

In general, control and safety valves are devices for controlling the flow and pressure of fluids. Control and safety valves are used in cases where there is a pressure difference in the fluid flow (both liquid and gas). To select control and safety valves, in addition to considering the type of valve required (the most critical types of which are mentioned below), it is necessary to consider the size, type of connection (gear or flange), working temperature, working pressure, type of flow fluid. , type of controllability and performance, body material, product brand, etc. Pay attention. In this article, we have tried to briefly introduce you to the types of control and safety valves and their operation.

Buy control and safety valves in installments

For your convenience, dear customers, the heating equipment collection has provided the possibility of selling in installments. You can refer to the installment purchase page to buy control and safety tires in installments.

The main functions of control and safety valves

• Complete disconnection and connection of current
• Prevent the return of liquids and gases
• Adjust the passage of the required amount of liquids and gases
• Adjust and control the amount and pressure of liquids and gases
• Control and keep devices under pressure

Safety Valves' Material

The materials vary according to the type, application, working pressure, etc. Cast iron, bronze, brass, and sometimes steel (SS) valves are commonly used in construction projects, while in industrial projects such as power plants, petrochemical plants, refineries, shipbuilding, the pharmaceutical/food industries, etc. Depending on the fluid that passes through the valve or the environment, the body and other components can be carbon steel, alloy steel, and stainless steel.

Control and safety valve categories

• Manually operated valves
• Automatic valves that work with the air force, control valves, and gases (control valves)
• Electric motor-operated valves

Types of control and safety valves

Control and safety valves have the following types (which we will examine in the following):

• Diaphragm valves
• Two-way and three-way motorized valve
• Pressure reducing valve
• Butterfly valves
• Safety valves
• Automatic valves
• Balancing valves
• Pressure relief valves

Automatic valves

Automatic valves are usually used with an automatic controller to control the amount of flow. Automatic valves

Automatic valves are usually used with an automatic controller to control the amount of flow.

Groupes of Control Valves

Control valves are divided into the following groups:

ACTUATOR Control Valves

A valve actuator converts the output signal from the controller (an electrical or wind signal) into linear or rotational motion. Operators come in various sizes, types, outputs, and mods.

The most common actuators used for automatic valves

• Magnetic actuators (SOLENOID)
• PNEUMATIC
• Electric motor
• Electronics
• Hydraulic
• Thermostatic

The radiator's thermostatic valve, with its air temperature sensor and the volumetric or longitudinal expansion of its actuator section (at the desired temperature), cuts off the radiator's hot water flow and maintains the room temperature balance.

Two-way (TWO-WAY SINGLE AND DOUBLE-SEAT)

In two-way automatic valves, fluid enters the inlet and exits from the outlet. Depending on the valve stem (STEM) position and the valve disc (DISK), whole or less current may flow through the valve. Two-way valves can have one or two valves. In the case of single-seat valves, a single seat and a disc are used to close the valve. Double-seat valves are two-way valves with two seats and two discs. These valves are used in cases where the pressure drop when closing the valve is more than the seat valves. Gradual, single-pulse, open normal, close regular, etc., are two-way automatic valves.

In some applications, these valves cannot be used due to the limited space or size of the existing mixing and dividing three-way valves. In such cases, levers will use two butterfly valves mounted on a three-way and connected. Note that the flow characteristics of butterfly valves differ from those of standard valves with a disc and seat, so using these valves is possible only in cases where their flow characteristics are responsive.

THREE-WAY VALVES:

In mixing three-way valves, the two currents are mixed. They are commonly used in HVAC systems to mix cooling or heating water. The application of these valves is to control the air temperature after cooling water coils. So, the cooling water of the coil is mixed with the warmer water returned from the coil. The same can be said for heating water.

Diaphragm valves

The curtain or diaphragm valve has a simple and exciting structure. Diaphragm valves consist of three critical parts:

• Body
• Diaphragm
• Bonnet

The diaphragm is made of a reinforced rubber curtain or other elastic material that moves up and down by moving the handle of the elastic curtain valve and increasing and decreasing the fluid passage, thus controlling the amount of fluid. The diaphragm separates the valve contents from the opening and closing mechanism, so there is no need for sealing devices. If material leaks around the valve, it indicates that the diaphragm is perforated and needs to be replaced. This type of milk is used to control corrosive substances such as acids.
Note that a diaphragm valve will be useless when the temperature is high because the diaphragm melts at high temperatures. Diaphragm valves are used only at low pressures and temperatures.

Pneumatic valves

Control valves need a unique stimulus to start their activity. Some work with electric or hydraulic actuators, while others work with pneumatic actuators, which are used more than other valves in water or gas pipelines. Pneumatic valves may be fully open or fully closed, or in different models, may be in other positions defined on them.

The general structure of pneumatic valves

• Control circuit
• Positioner (which adjusts valve mode and fluid flow rate)
• Mechanical valve (usually ball or butterfly type)
• Pneumatic power generator

Pneumatic valves take a while to open and close. Some are single-acting, and some are gradual. Consider the length of time that pneumatic valves need to open and close in the design of the pipes.

Pressure reducing valve

The pressure relief valve reduces the current fluctuations in the installation by reducing the pressure and keeping it at constant pressure. The outlet pressure in the breaker valve is constant even when the inlet pressure fluctuates. Still, whenever the user wants to adjust the outlet pressure according to his needs, he can adjust the outlet pressure by using the upper handle of the valve.
This valve can be called a fully automatic device because it has a particular structure for making changes and reducing pressure, which does this without transferring energy. The water inlet pressure can also be adjusted using the pressure relief valve. (Even when there are extensive inlet pressure fluctuations.)
A pressure relief valve or pressure regulating valve is usually installed near the water meter of buildings after branching from the main water pipe of the city to reduce high pressures and changes in the city's water pressure. These valves have a unique screw for adjusting the pressure and regulating the valve's outlet pressure.

Butterfly valves

Butterfly valves are commonly used in oil and petrochemical units. Their structure has a typical body and a circular plate almost in the middle. The plate rotates around a bar at 90 degrees and connects to the valve's moving part. This actuator can be manual or by air pressure or electricity.
They make small butterfly valves from 4 inches to 24 inches; They are easy to repair but must be lubricated regularly. In exceptional cases, some of them are equipped with a hand pulley connected to the plate's rotating rod, and its mechanism is located in a gearbox. If the main drive, air or hydraulic, fails, they can hold the plate in any position by releasing it from the gear with a lever or hand pulley.
The use of butterfly valves in units with low pressure during operation is widespread due to the minimal pressure drop. Another feature of these valves is to maximize the fluid flow rate in the minimum time and movement of the valve. Especially in fluid pressure control in pressure tanks or towers, these types of valves are used to transfer fluids in large volumes.

Practical advantages of butterfly valves

• Easy to use
• No slippery and sliding parts
• Reduce pressure drop
• Ability to control
• Cheapness and lightness
• Do not combine the plate's fabric with porous chemical or petrochemical products.

butterfly valves usages

• Thermal power station
• Hydroelectric power station
• Industries, especially oil and gas
• Water and sewage piping

Safety valves

Safety valves are a piece of special equipment that makes a unit safe against sudden pressure increases. The safety valve is a suitable device to prevent sudden pressure increases in engine rooms, factories, and generally all industrial units and for different fluids such as gas, steam, water, or compressed air.
Pressure limitations in such applications, which usually result from the tolerable pressure of equipment, pipes, and devices or manufactured products, as well as issues related to maintaining the safety of people, are called safe operating limits for pressure (safe operating limits for pressure) or SOL / P is famous. How to open the safety valves and their working specifications are directly related to how the internal components of the safety valve are designed. In most cases, this design is done so that after opening the safety valve due to pressure increase, due to the property (POP Action), this action is intensified quickly until the valve is fully returned.

Safety valves categories

They are used for gases, air, steam, etc. (except liquid). Safety valves automatically prevent an unauthorized increase in pressure relative to the defined and permissible pressure on pressure vessels and the piping system.
Safety valves automatically prevent excessive gas and liquid pressure. In other words, when necessary, the required amount of gas, steam, water, or air is discharged from reaching the permissible pressure of the device.

Safety valves types

• Safety valve with spring
• Weighted safety valves
• Safety valves with springs and diagrams

Safety valves are designed to open at a specific pressure. These valves are divided into three types:

Safety valves installed on sources, tanks, and gas devices are called safety valves.
Safety valves installed on sources and liquid devices are called relief valves.
Valves installed on gas and liquid sources and devices are called safety relief valves.

Balancing valves

Manual balancing valves can be rotary (stem), ascending (RISING), or non-ascending (NON-RISING). Generally, the structure of these valves has a moving part with an orifice that adjusts its position according to the compressive forces and, thus, will change the flow passage area. With this valve, when the pressure drop in the valve changes, the fluid flow will reach a predetermined value.

Pressure relief valves

Safety valve and pressure relief valve are usually used interchangeably. The appearance and function of both types of milk are the same, and it is to limit the amount of pressure of a liquid, vapor or gas by discharging part of that fluid. Safety valves are commonly used for air and water vapor. These valves are characterized by their rapid opening and closing. Pressure relief valves are generally used for liquids, and they open or close slowly when the pressure is high or low.

Purchase order and guarantee of control and safety valves

• In the group of control and safety valves of DamaTajhiz, the reference website, information and prices for wholesale purchase of various types of water and fuel solenoid valves, motor valves, gas control, and safety valves, steam, pressure breaker, and pneumatic see Danfoss, Dangar, CSCase, Honeywell, Takban, Hisco brands to review and select.
• Because all products on the Damatajhiz website are provided with an original warranty, if you bulk buy any control and safety valves, all the special sales discounts of each brand, such as Danfoss, Dangar, CS Case, Honeywell, Takban, Hisco ... will be included in your offer. (Ask Damatajhiz experts for the specialized sales of control and safety valves)
• After reading the above, if you have any more questions to decide to buy any kinds of control and safety valves in bulk, you can contact us through email or whatsapp to get advice and ask your questions.