The creators of the pipeline systems hoped that water or any other product would move in one direction. But practice shows that there are exceptions. To avoid emergency situations, if the flow goes the other way, a non-return valve or one of its varieties, a ball valve, is used in the pipelines. Consider the device and the principle of operation of the check valve and, in particular, ball elements. We also learn how to choose the right device.
Device
A typical ball valve is a cylinder with a spring and a locking device inside it. In our case, this is a ball. In other types of mechanisms, a plate may be used. In the basic assembly, the valve is closed due to a spring located inside. However, under the influence of flow, this part can reduce the pressure force, and the valve opens. A stream will go through it.
If the pressure decreases (and this can happen due to leaks, stopping the pump system or for other reasons), then the locking mechanism will close under the action of the spring force. If the pressure will move towards the valve, then, thanks to the locking element, the liquid will not be able to pass.
Types of mechanisms
In today's market you can find a lot of devices - they vary in characteristics and cost. As for materials, most often these products are made of carbon and stainless steels, cast irons, brass, bronze and even plastic.
Wafer Disc Valves
The design of this mechanism is a spring. Such solutions are considered the most compact among what is released by modern industry. A disk equipped with a spring is used as a shutter.
The overall dimensions of such devices can be from 15 to 20 mm. The principle of operation is simple. If pressure begins to drop in the pipeline, the spring will press the plate or gate disc against the seat. The flow hole is blocked. After the pressure is restored to the desired level, the spring will be squeezed out and the fluid can again flow. In serious and large pipeline
hydraulic systems , bivalve structures equipped with shock absorbers are more often used. Using these elements,
water hammer is mitigated when the pump stops. The principle of operation is quite simple. The valve works until the reinforcement folds in half under the pressure of the flow. If the pressure goes in the opposite direction, then the plate will return to its normal position. Such a valve has sizes from 50 to 700 mm.
Advantages of Wafer Elements
Among the advantages, reviews note compactness and low weight. The design does not have flanges, so they are significantly smaller than ball check valves. Also, the device has less weight. Other advantages include the ability to install not only horizontally, but also vertically. Installation of these systems is also not difficult, which is a big plus. The disadvantages include the need to dismantle the device for repair.
Lift valve
In these systems, a special lifting spool is used as a shutter mechanism - hence its name.
If the medium pressure in the pipeline is not too high, then the element will lower into the seat, thereby blocking the flow back. When the pressure is high enough to operate the system, then the element will rise. These solutions are installed only on horizontal sections in the pipeline. It is very important that the axis of the spool is strictly vertical.
The ball valve in this regard is much simpler. Such requirements are not imposed on him.
Ball Reverse
This design differs from all others in that a ball is used as a locking element, which is pressed by a spring. Ball check valves, for all their simplicity, have many advantages and are widely used not only in plumbing, but also in large pumping stations, as well as in various industries. As already noted, a ball is used here as a locking element.
This is a special element made of cast iron or aluminum, which is coated with a layer of rubber. Thus, the ball valve effectively prevents the reverse movement of the medium. When the fluid moves in the right direction, the element is pushed up the housing - there is a special niche for it. If the direct flow movement stops, under the weight of its own weight, the ball will slide into the lower part of the body and thereby block the movement of the medium. The ball check valve is also convenient in that a special cover is installed in the upper part of the device with the possibility of its removal. It is designed to carry out minor repairs and maintenance of the mechanism without the need for a complete removal of the device.
The cover is fixed to the housing by means of bolts. And to reduce the risk of leaks, it is additionally equipped with a rubber o-ring. In everyday life and in industry today they use automatic solutions. They are necessary in order to block the movement of the medium if the operator for some reason cannot do this. Here they use a valve on a ball valve equipped with automation. Reviews indicate usability.
Electronics will independently block the movement of the medium in the other direction and turn off the tap. This solution allows you to secure hydraulic systems.
Installation requirements
The ball check valve must be installed correctly - the only way he can correctly perform his task. If the installation is horizontal, then the compartment with the ball should face up. Only in this case the element rolls down. If the installation is vertical, then the direction of flow should be from the bottom up.
Ball Valve Characteristics
One of the main characteristics is the diameter of the bore or the nominal diameter. This parameter is referred to as DN. Reviews say that this parameter is conditional and does not always correspond to the actual internal diameter of the pipeline. It is also necessary to take into account the wall thickness of the pipes. Other factors to consider when choosing a valve. For example, a parameter such as nominal pressure is important.
This is the maximum value at which the ball flange valve can be operated safely. All permissible numbers are indicated in GOSTs - you can focus on the index 26349-84. Also, the choice should apply European and American standards.
Connection types
By the type of installation, check valves may vary. For example, for polypropylene pipelines, the element is only welded. There is also a ball valve flanged. What is this type of connection? Here the fastening is carried out through the flanges, but this is relevant only for large diameters. You can still highlight an alternative connection method by means of a threaded sleeve. Reviews say that this option can only be used on pipelines of small diameters. And finally, the wafer type connection. Here the valve is installed between two elements in the pipeline.
Manufacturers and prices
Among the products that are presented in stores for household pipelines, one can find both imported European products and domestic ones. The price depends on the characteristics, namely the bore diameter, as well as working pressure and other parameters. For a pipeline with a diameter of 50 mm of a domestic manufacturer, the ball price for the valve will be 1,200 rubles.