Devices that restrict the flow of incoming liquid or gas in a pipeline are called control valves. This mechanism is widely used in the water and gas supply system in domestic premises, in industries, as well as in heating systems.
What is a control valve made of?
The control valve consists of a handle and a working part. Its handle is made in the form of a disk or lever with a rubber gasket. To seal the stem of the valve handle, a rubber seal is often used, which also presses the nut. The working part can be made of brass, nickel-plated or plain, polypropylene, steel or cast iron. Handles can be metal, plastic, chrome or painted.
In most cases, a valve with a loose nut comes from the factory so that the gasket does not deteriorate during transportation and storage. Therefore, before starting operation, this nut must be tightened. In some cases, on the body of control valvesthere is an arrow indicating the direction of liquid or gas flow.
How does the mechanism work?
The principle of operation of control valves is very simple. The disk with the gasket moves towards the body from the valve, thereby smoothly regulating the flow of liquid or gas. In the extreme positions of the handle, the valve is completely closed or open. If there is a wedge-shaped element in the valve, then it is he who moves up and down inside the body, and thereby regulates the flow. If a disc is provided in the valve, then its principle of operation is exactly the same as the wedge - it moves up and down the valve and regulates the flow. If there is a rotating disk, then it does not move up and down, but rotates inside the housing, thereby regulating the flow. These valves are often referred to as gate valves.
Valve body shape
According to the shape of the structure of the body, it can be straight control valves, which means they are installed only on straight sections of the pipeline, and angular, that is, the mechanism is attached to the place where the pipeline bends.
Locking mechanism
The visual difference of the locking mechanism divides the valve into varieties:
- with a ball-shaped locking mechanism that, when aligned with the through hole, shuts off the flow of liquid or gas;
- with piston lock, which, when lowered into the hole, stops the flow of liquid or gas.
Often for water supply system andheating, it is recommended to use a 1/2 inch control valve with a piston lock, and for a gas pipeline - with a ball-shaped mechanism.
Flow adjustment
Flow control valves include:
- manual feed and adjustment, which is adjusted by turning the head or adjuster lever;
- automated feeding and adjustment, which are equipped with devices that independently support all parameters.
Valves with automatic flow control are widely used in heating systems, where it is important to maintain a very accurate temperature environment.
Pipe connection method
Shut-off and control valves according to the method of connection with the pipeline can be divided into:
- devices fixed with threads at the ends. Such a mechanism can only be installed on the thread, and optionally also removed. A feature of this fitting is the presence of special sealing gaskets attached to it;
- devices with flange clamps. Products are also popular due to the fact that there is always the opportunity to install or remove them;
- devices mounted by welding. The products are very reliable, but do not have the ability to shoot mobile and quickly.
Where are they used?
According to their intended purpose, control valves are used in the gas pipeline system. This mechanism is distinguished from other very highhigh pressure resistance and durability. For the most part, they are equipped with adjustment sensors (pressure gauges). In the water supply system, valves are highly resistant to water pressure, as well as various kinds of deposits. In heating systems - endowed with qualities to withstand elevated temperatures and corrosive effects.
Install the valve
Installation and installation of a valve with a shut-off and control mechanism takes place according to a simple but very effective scheme:
- choose the installation location. It is most advisable to install the valve in a place where there is free access and space in order to easily carry out both the installation itself and further operation;
- installation of threads on the edges of the pipeline. If the thread is installed, then you can proceed to the next step;
- sealing threaded connections. For this stage, it is necessary to use a sealing thread or special gaskets;
- installation of fittings. During installation work, care must be taken not to overtighten the threaded connection;
- check. It is necessary to check the mechanism for tightness and for the direction of the pressure supply.
Helpful tips
When choosing a control valve, you should pay attention to the diameter of the pipeline where the fittings will be attached, and the throughput of the valve. Each valve in its diameter must exactly match the diameter of the pipe. If this factor is not observed, then there is a risk of leakage, or the valve simply will not fit.
Each valve has a flow capacity. Experts recommend always having a margin of safety of 20% or more of the designated holding time of the pipeline itself. If these factors are not taken into account, the operation will be incorrect and eventually lead to a malfunction of the fittings and pipeline.
