In the article we will talk about 3-way valves with and without electric drive. There are a large number of valves, but such devices are used quite rarely. The design is somewhat reminiscent of a tee, but only the functions of the device are different. Why is a valve of this design needed and how does it work? Let's try to answer these difficult questions.
How does a valve work?
A valve is installed in sections of the pipeline where it is necessary to divide the fluid flow into circuits with a constant and variable hydraulic regime. It often happens that a constant flow is necessary when a high-quality liquid is supplied in strictly defined volumes. A variable flow is used, as a rule, at those facilities where the quality of the fluid does not play a big role. More emphasis on quality factor.
Please note that 2-way valves are also shutoff valves. But the difference from the 3-way valve is that the principle of operation is somewhat different. The design has a rod that does not block the flow of coolant with constant hydraulic performance. It turns out that it is constantly in the open position, adjusted to a certain volume of coolant. Using the device, you can adjust the required volume of coolant both in terms of quality and quantity.
Mixing devices
Devices can be divided into two large subgroups:
- Mixing.
- Separating.
Features of functioning can be seen from the names. The mixer has one input and two outputs. In other words, with the help of such devices, two coolant flows are mixed. This is usually necessary for cases where it is required to lower the temperature of the liquid. Typically, such designs are used when adjusting the temperature of a warm floor.
The adjustment process is simple, it is enough to know the temperatures of the flows that enter the valve. It remains just to calculate the proportion, and this is a school mathematics course. By the way, if you carry out installation and adjustment correctly, you can make it so that the device can easily separate flows.
Separating valves
As for the second type of valves, they are able to divide one flow into two. Its design provides for the presence of one entrance and twoexits. The device is used, as a rule, if it is necessary to carry out the separation of the flow of hot liquid in the DHW system. Often it can be found in the strapping of air heaters.
Design features
Structurally, both types of valves are similar. But if you look at the drawing, which is given in our article, the differences are immediately evident. A stem with one ball valve is installed in the mixing valve. It is located in the center and closes the main passage. In separating devices, the stem has two of the same valves, they are installed in the outlets.
Work is as follows:
- One of the valves is pressed against the seat and closes the passage.
- The second valve, on the contrary, opens the passage.
There are manual and electric devices. This is one of the options for classifying appliances.
Manual and electric
The most commonly used devices are manually operated, outwardly they are similar to simple ball valves. Here are just three outlet pipes for connecting to highways. Electrical devices have fully automatic control, they are usually used in private homes. Moreover, such devices allow to distribute heat as evenly as possible. And the control system allows you to set your own microclimate in separate rooms. Quite often, such devices are mounted for the functioning of the underfloor heating system.
Required when installing 3motorized directional valve, system pressure and line diameter must be taken into account. These parameters must match exactly.
Buying a valve: what matters?
Manual flow control is done with simple ball valves. The appearance is the same as that of a conventional valve. But there is an "extra" way out. Similar fittings are used to carry out forced manual control.
Automatic devices are equipped with an electric motor or relay. They allow you to change the position of the stem. This drive is connected to a thermostat so that the temperature in the line can be adjusted. When buying a 3-way valve with an actuator, you need to pay attention to the following points:
- Diameter of branch pipes for connection with the heating main. As a rule, the values are in the range of 20..40 mm. But it all depends on the specific highway and its features. In the event that it is not possible to find devices of suitable diameter, you can mount adapters.
- Is it possible to install a servo on the device. After all, if there is such an opportunity, then a manual valve can be easily turned into an automatic one.
- What is the capacity of the highway.
Installation of mixing devices
The scheme is used, as a rule, in boiler houses connected to hydraulic separators or non-pressure collectors. The circulation of the coolant in this case is carried out due to the operation of the pump. If the valve is connected directly to a heat source on the bypass, then the device must be connected withhydraulic resistance, like a boiler. In the event that this nuance is not taken into account, the fluid flow will fluctuate over a wide range.
It is not recommended to install a 3-way mixing valve to a pressure manifold or heating networks. But only if there are no devices throttling excessive pressure. Otherwise, significant fluctuations in fluid flow will be observed. In order to get rid of excessive pressure, it is allowed to install a jumper parallel to the valve admixture.
Separating valve mounting features
The installation diagram is given in the article. The main task of this device is to perform quantitative adjustment by changing the cost of the coolant. Earlier we considered the principle of operation of such devices, so we will not mention them anymore. Installation should be carried out in places where it is possible to transfer the coolant to the return line. This does not allow stopping the circulation.
Please note that the bypass and consumer balancing valve losses must be equal. This will link the hydraulic circuits. The pressure in the system is created by the operation of the pump. Installing a 3-way control valve allows you to distribute fluid flows under pressure into two lines. But it is possible to realize this only in systems in which there is constantly high pressure. That is, subject to the availability of a pump.
