Devices that restrict the flow of incoming liquid or gas in a pipeline are called control valves. This mechanism has become widespread in the water and gas supply system in domestic premises, in factories, as well as in heating systems.
What does a control valve consist 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 valve handle stem, a rubber seal is often used, which also presses the nut. The working part can be made of brass, nickel-plated or plain, of 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, an arrow is located on the body of the control valves indicating the direction of flow of the liquid or gas.
How does the mechanism work?
The principle of operation of control valves is very simple. The disk with the gasket moves to 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, it is he who moves up and down inside the body, and thereby regulates the flow. If a valve 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 case, thereby regulating the flow. Such valves are often called gate valves.
Valve body shape
According to the shape of the body structure , these can be direct control valves, which means that they are installed only on straight sections of the pipeline, and angular, that is, the mechanism is fixed at the place where the pipeline is bent.
Locking mechanism
The visual difference of the locking mechanism divides the valve into varieties:
- with a locking mechanism in the form of a ball, which, when coincident with the through hole, blocks the flow of liquid or gas;
- with piston lock, which when lowered into the hole stops the flow of liquid or gas.
Often, for a water supply and heating system, it is recommended to use a 1/2-inch control valve with piston lock, and for a gas pipeline - with a ball-shaped mechanism.
Flow adjustment
Valves for adjusting the flow rate include:
- manual feed and adjustment, which is adjusted by rotating the head or lever of the regulator;
- automated feed and adjustment, which are equipped with devices that independently support all parameters.
Valves with automatic flow control have found their distribution in heating systems, where it is important to very accurately maintain the temperature environment.
The method of connection to the pipeline
Shut-off valves according to the method of connection to the pipeline can be divided into:
- devices fixed with thread at the ends. Such a mechanism can only be installed on the thread, and optionally also be removed. A feature of this armature 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 fast.
Where are used?
For their intended purpose, control valves are used in the gas pipeline system. This mechanism is isolated from others by a very high resistance to high pressure and durability during operation. For the most part, they are equipped with adjustment sensors (manometers). In the water supply system, the valves are highly resistant to water pressure, as well as various kinds of deposits. In heating systems - endowed with the qualities to withstand high temperatures and corrosive effects.
Install the valve
Installation and installation of a valve with a locking and regulating mechanism is carried out according to a simple but very effective scheme:
- choice of 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 the installation itself and further operation;
- threading on the edges of the pipeline. If the thread is installed, then you can go to the next step;
- sealing threaded connections. For this stage, you must 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 flow of pressure.
Useful Tips
When choosing a control valve, you should pay attention to the diameter of the pipeline where the fittings will be mounted, and the valve capacity. Each valve in its diameter must exactly match the diameter of the pipe. If this factor is not observed, that is, there is a risk of leakage, or the valve simply will not work.
Each valve has a flow rate. Experts recommend always having a margin of safety of 20% and above the designated exposure time of the pipeline itself. If these factors are not taken into account, the operation will be incorrect and, as a result, will lead to malfunction of the fittings and the pipeline.