To change the flow rate of transported media to a complete stop, shut-off and control valves are used. The water tap for water has the following properties:
- simplicity of design and operation;
- high pressure drop applications;
- small size and weight;
- possibility of installation on any section of the pipeline;
- Short shutter travel for easy maintenance.
Valve types
Shutoff and control valves are classified according to three criteria:
- body shape;
- view of obturator;
- mounting method in the system.
According to the shape of the body, the valves are as follows:
- straight-flow - the flow is blocked by the valve seat in the transverse direction;
- angular - the locking element moves towards the movement of the medium;
- mixing - to obtain the desired water temperature.
The locking element differs in design:
- Ball - a through sphere in a straight-through housing. When the longitudinal axes of the hole and the body are aligned, the flow movement is completelyopens. Turning in the perpendicular direction 100% shuts off the flow of fluid. The valve performs the function of only a locking element, and it is not suitable for regulation. The use of the device is associated with its high reliability, speed of shutting off the flow and compactness. Almost nothing breaks in it, since there are very few parts.
- Valve - with a constipation associated with a threaded rod screwed into the seat nut. The unit is used to control the flow and to completely shut off the flow (in the lowest position).
- Needle-conical piston with high pressure fluid flow control (about 220 bar).
Valve materials:
- ball: brass, stainless or structural steel;
- valve: cast iron, brass.
New materials are also being used to make valves. The polypropylene body makes the device durable and cheap at the same time. Fluoroplastic coatings improve resistance to corrosion and aggressive environments.
The difference between a valve and a faucet
Water faucets and valves are different, although they are often identified. The latter is installed between the joints of two pipes, forming a line. The faucet includes a direct valve and a spout through which water flows out.
Design and operation of the valve valve
The most important working body of the valve is the saddle with a valve manually moved by a spindle. Valve valve for water, devicewhich is given below, contains a thread in the body and on the stem, which has the property of braking. As a result, the valve disk is pressed tightly against the seat, shutting off the flow when the valve is closed. In the open state, the flow area remains unchanged during the movement of the water flow.
No threads are usually made in the body, as it wears out quickly. To do this, a running nut is attached to it, into which the spindle is screwed. Then, instead of a worn-out node, you can install another one, while the body will remain. All parts are interchangeable with a water valve (GOST 12.2.063-81, GOST 5761-74).
The valve is opened by turning the handle. In this case, the spindle moves forward, freeing the passage for the liquid. If the rotation is reversed, the valve will close.
The device is connected to the pipeline through the inlet and outlet pipes. They can be distinguished from each other by the presence of an arrow indicating the direction of flow.
Angle valves
For a perpendicular change in the direction of fluid transfer with the possibility of overlapping and adjustment, an angled water valve is used (drawing below: a - straight; b - angular).
The perpendicular arrangement of the inlet and outlet pipes determines the purpose of the valve for pipelines that change direction by 90o. The principle of its operation is the same as that of the through passage. The valve stroke is made coaxially with the inlet.
Spherecorner valve applications:
- When pipes are connected to a heating radiator, when it is blocked or regulated by a water valve (see photo below). Models made of high-temperature polypropylene are more convenient and cheaper than brass models when connected to plastic pipes.
- Prevention of vibration and swaying of pipelines.
- Decrease fluid flow rate without high frequency noise.
- In fire-fighting water pipes when operating in any position.
- Simplify pipe installation by reducing hardware consumption.
Design and principle of operation of the ball valve
The main working body of the valve is a ball with a through hole. When the handle is positioned along the pipe, the valve is open. If it is turned perpendicular to the pipe, it will close. The hole in the ball can be round, square, in the form of a trapezoid or an oval. In valves of small diameter, the valve is made floating, and for large-sized devices it is made on special supports. High tightness of the shutter is provided by an elastic seal. This allows you to install this type of models on gas pipelines.
The water ball valve operates in two extreme positions when rotated 90o when it is fully open or closed. Attempting to control flow will result in rapid seal wear.
Ball valves have more options for connecting pipes when installing water supply systems:
- checkpoints;
- corner;
- with three or more taps to redirect transport flows.
Connections with pipes are made by fitting, flanged and welded. The last option allows you to permanently install a water valve in the system.
Shower taps
The device is made as a single-lever ball valve or in the form of two valve valves. The kit includes a replacement shower head with attached flexible hose and bath spout. The mixer is hidden, bringing out only the water temperature control valves.
The classic option is a two-valve accessory with manual temperature control. Cold and hot water are mixed in a special chamber, and then flow into the shower hose or spout. The main elements of the device are two crane boxes with replaceable gaskets.
The single-lever device with convenient water adjustment is becoming popular. The main element of the mixer is a replaceable cartridge. In case of failure, it can be easily removed and replaced with a new one.
Easy to adjust with integrated thermostat. It is pre-configured, which guarantees the output of water at a given temperature. To do this, there is a thermostatic element in the housing that distributes the flows. The only drawback of such models is the high price.
Installation
Valves of small diameter are mounted on threads (up to 60 mm). There is a drive on the pipe, the connection is sealed with hemp or fluoroplastic film. Winding is carried out in the direction of thread twisting. This creates a tight connection that can withstand high pressure.
The large diameter pipe is flanged to the washer of a straight or angle valve through a sealing gasket. They are fastened together with bolts and nuts. The flange is connected to the pipe by arc welding.
Water valve: repair
If the shut-off element of the valve is damaged, it is replaced with a similar unworn or new assembly. To do this, the pipeline section is freed from liquid, blocking it from both sides. Then the valve-type shut-off element is dismantled. The ball valve is removed completely with open-end wrenches or adjustable wrenches. On the flanges, the nuts are twisted in parallel and gradually - 3-4 turns on each.
First, you should check the he alth of the seals, which are replaced when worn. Most leaks are due to deformation of gaskets and thread stripping due to improper installation. Then the body and seat are inspected. In the absence of cracks, the assembly is assembled again. The case cannot be repaired if mechanical damage appears on it. Growth to the pipeline requires its cutting and the need for further welding.
In this case, you will have to install a new or repaired water valve. An unprepared person should not undertake complex repairs because of ignorance of its features.
Stop valves create additional resistance, so in placesconnections may become clogged. It is not always necessary to remove the valves. Sometimes it is enough just to flush the pipelines by opening all the taps.
Replacing the oil seal can be done carefully with your own hands. To do this, turn off the water supply from the riser, disassemble the locking mechanism, replace the gaskets and lubricate the moving parts.
Conclusion
The water supply valve is easy to operate and does not require much maintenance. Each model should be used for its intended purpose. A simple valve repair can be done by hand if you act carefully and correctly.
