Electronic valve for gas. How does a gas solenoid valve work? Solenoid gas valves

Multifunctional solenoid valves for gas belong to the category of pipeline fittings. Devices serve for distribution, regulation, cutting off working environment in boilers, geysers, pipelines and other gas equipment. The magnetic valve of the valve is controlled remotely, in automatic mode, this is its advantageous feature. The relay turns on or cuts off the electrical current to the coil, the plunger rises or falls, opening or closing the hole, thereby controlling the gas flow.

The price for a solenoid gas valve is higher than for similar mechanical devices. The costs of its acquisition are recouped due to the ability to conduct technological processes in an optimal mode with minimum consumption fuel. In addition, the devices are recommended for installation, since they greatly increase the safety of operation of boilers, water heaters, and furnaces. In the event of a fuel leak, the magnetic choke will immediately shut off the gas supply, thereby preventing dangers associated with concentration harmful substances in room.

Multi-purpose fittings are used to service domestic and industrial installations, and automotive systems.

Device, principle of operation

The main elements are the seat and the bolt. The seat can be in the form of a piston or a plate; the configuration of the shutter varies, depending on the modification. The shutter is mounted on a core connected to an electromagnet. Opening and cutting off the gas supply occurs due to the reciprocating movements of the shutter. The magnetic mechanism is mounted on the outside of the valve body.

When electric current is applied to the magnetic component, a magnetic field is generated, which shapes the direction of movement of the gate. When the valve is operating, the electromagnetic unit is affected by the resistance force of the return spring and a magnetic field, the strength of which depends on the strength of the operating current. When the device is disconnected from the power supply, it returns (remains) to the position determined by the type of its design.

Alloys are used to make the valve body and covers stainless steels, brass, cast iron, polymers (ecologist, nylon, polypropylene). The plungers and rods are made of magnetic compounds.

The valve is connected to the pipeline using a flange or threaded connection. To the electrical network - using a plug.

Varieties

Solenoid valves are characterized by a variety constructive solutions Therefore, they are classified according to many parameters.

The valves are classified according to the opening method:

• normally open (NO); they remain in the open position when the power supply is interrupted, thereby ensuring conditions for the passage of the maximum volume of flow;
• Normally closed (NC): in the absence of current solenoid gas shut-off valve The NC is closed, thereby completely blocking the flow;
• universal: such models can remain in the open or closed position when the power supply is interrupted.

In modified modern models the possibility of reconfiguring the pilot position of the membrane is provided. Devices with a NO plunger position can be converted to NC type valves.

Depending on the type of design, the valves can have a conventional or explosion-proof design. The latter are recommended for installation on objects that require high requirements on explosion fire safety (enterprises in the chemical, petrochemical, gas and other industrial sectors).

Solenoid valves for gas It is also customary to classify according to control features into devices of direct action and those driven by piston (diaphragm) force.

• Direct-acting valves have a simple design, are characterized by fast operation and high reliability. In such models there is no pilot channel. Opening occurs instantly when the membrane is lifted. With absence magnetic field the spring-loaded plunger is lowered. Models of this type do not require a pressure differential to operate.
• Models with piston (diaphragm) force are equipped with two spools. The function of the main one is to close the main hole; the control spool is responsible for the operation of the relief hole, which serves to relieve pressure from the area above the membrane. Due to pressure compensation, the main spool rises and the main passage opens.

Based on the number of pipe connections, solenoid valves are classified into two-, three- and four-way valves. Two way valves are either NC or NC type and have one inlet and one outlet pipe connection. Three-way valves have three connections and two flow sections. They come in NO, NC type and universal, and are in demand for organizing work automatic drives, distribution valves, cylinders with one-way vacuum action, alternating pressure supply. Four-way ones are equipped with four or five pipe connections. One connection for pressure, one or two for vacuum, two for the cylinder. Such models are necessary for the operation of automatic drives and double-acting cylinders.

Modern gas equipment in heat supply systems involves the use of a wide range of pipeline fittings. These are means of regulation, protection and control that ensure stable and safe work target unit. Thus, a new generation of shut-off valves is represented by an electromagnetic gas valve designed to distribute and regulate the supply of the working mixture.

Device design

Solenoid valves are also called solenoid valves because they are based on a solenoid in the form of a coil. It is enclosed in a metal case, complete with a lid and outlet openings. In addition, the working structure consists of pistons, spring block and a rod and plunger that directly control the gas solenoid valve. The design of the coil may vary depending on the type of medium and its pressure, but most often it is a winding with high-quality enamel wire in a dust-proof housing. The cores are made of electrical copper.

Depending on the type of equipment, different connection system configurations may be used. For geysers Usually a flange or threaded method of connecting to a pipeline is used. The network connection in the case of household circuits is made through a 220 V plug. In the future, the electromagnetic gas valve can be supplemented with auxiliary fittings and control and measuring devices.

Performance properties of materials

Since it initially focuses on special conditions applications, special plastics are used for the basis of the structure. For example, EPDM polymer provides the device with resistance to chemical influences, aging and pressure changes. With this design the valve can be used in temperature conditions from -40 to 140 °C, but it is not recommended to use it in gasoline and hydrocarbon environments. Another modern variation of the polymer alloy is PTFE. It is polytetrafluoroethylene that can withstand high concentration acid mixtures. IN in this case contact with aggressive gas environments and operation in temperature range from -50 to 200 °C. It is not recommended to use PTFE polymer where there is a risk of contact with trifluoride chloride and alkali metals. At the same time, protective qualities are not always the main requirement for a solenoid valve. Gas shut-off valves for the same household supply networks may well be made from inexpensive elastic polymers like butadiene-nitrile with a rubber base. This material copes well with the maintenance of butane and propane mixtures, but at the same time it is afraid of strong oxidizing agents and ultraviolet radiation.

Working principle of solenoid valve

The state of the valve is influenced by an electromagnetic coil, the pulses of which activate the shut-off elements. The static position of the valve is characterized by its closedness. In this position, the locking membrane or piston element is hermetically pressed against the outlet circuit, preventing the passage of the working mixture. The pressing force is also provided by direct pressure from the gas mixture from the side of the passage. On the main pipe, the electromagnetic gas valve is additionally locked with a plunger until the voltage in the coil changes. At the moment of exposure to the magnetic field in the solenoid, the central channel begins to open, where the spring-loaded plunger is located. As the pressure balance changes on different sides of the valve, the piston group with the membrane also changes its state. The armature remains in this position until the voltage on the coil decreases.

Features of a normally open valve

The operating principle of the most common statically closed structure was described above. In case of normal open valve regulation is carried out differently. In the normal position, the shut-off elements provide free passage for gas mixtures, and the supply of voltage, accordingly, leads to closure. Moreover, maintaining a long-term closed state for safety purposes is possible only with long-term and stable support of the specified voltage. An even more functional solenoid valve for gas boiler does not act directly, but with a technological pause. In a short period of time, the system evaluates whether other safety conditions in the mixture supply circuit are met. The coil voltage itself does not initiate valve closure. But if indirect conditions are met, then it works automatically. The decisive factor, in particular, may be a certain voltage value, the same stability or a given amplitude of pressure drops.

Types of device

Valve regulators for geysers are distinguished by the number of output channels. Typically two-, three- and four-way models are used. The basic two-way version has an inlet and outlet channel, and during operation, accordingly, serves to supply and close the connecting unit. As the design becomes more complex, the number of input holes increases. A three-way gas solenoid valve, in particular, provides not only throughput, but also redirection of the working medium to one or another circuit. Devices with four channels operate on the principle of a collector, distributing gas along different supply lines.

Conclusion

When choosing suitable shut-off valves, it is important to take into account many technical and operational parameters. At a minimum, you should rely on structural and electrical characteristics that will allow you to correctly integrate the device into the target channel. As for the protective qualities, it is advisable to give preference to solenoid valves for geysers with an insulation class of IP65. Such products are dust-, moisture- and shock-resistant, which ensures a long service life. With regard to the connection configuration and operating principle, the choice should be made based on the nature of the column’s operation, gas supply volumes and other nuances of the equipment’s operation.

Gas equipment protection systems block the flow of energy in the event of emergency situations. Operation without them gas installations prohibited. Security elements include gas valves electromagnetic type.

Solenoid gas valves

Devices of this type belong to pipeline fittings and are used to distribute the gas flow and cut it off if necessary. They received wide application both in individual gas equipment and in industrial ones. The device is controlled automatically under the influence of voltage.

Electromagnetic gas valves are installed at the inlet of the gas pipeline in front of the following consumers:

• boilers;
• automotive gas equipment;
• entering a pipe into a multi-storey building.

Most gas valves have closed design, that is, in the absence of voltage, the valve closes the pipe.

Construction of gas solenoid valves

Solenoid type gas valves consist of electrical and mechanical parts. The electrical system is used to control the system, while the mechanical system is the actuator. The entire circuitry of the device is located in the housing. The main operating components are the so-called seat and bolt. The seat is a hole through which the gas flow passes and is closed by a valve. The latter is designed like a plate or piston. The shutter is mounted on a rod, which is part of the electromagnetic system.

The electromagnetic system consists of a coil within which a core moves. It is connected to the bolt rod. The electromagnet itself has its own plastic housing and is located outside on top of the valve body. The operation of the electromagnet is counteracted by a return spring.

Solenoid gas valves operate according to to the following principle. In the initial state, when there is no supply voltage at the electromagnet terminals, the return spring holds the gate in a certain position. This position often corresponds to a closed channel in the valve. As soon as power appears, under the influence of magnetic force, the shutter core is retracted, overcoming the force of the return spring, and the shutter opens the channel. Some valves are brought into operating position by manually cocking (opening) the shutter. By using the current supplied to the electromagnet, the magnitude of the magnetic flux of the electromagnet can be adjusted. In this way, the operation of the valve is controlled by not opening it completely, thereby regulating the gas flow.

Types of Gas Valves

Solenoid gas valves come in various configurations and internal structure, but they are all divided into:

• Closed in in good condition(NZ). That is, if there is no voltage, the gas is shut off. These are basically emergency type valves.
• Opened in normal condition (NO). Gas flows freely if there is no voltage on the coil, and is closed when a control signal is applied.
• Universal type. In such devices, it is possible to switch the position of the shutter, which can be either open or closed, in the absence of power to the electromagnet coil.

According to the principle of actuating the shutter, the electromagnetic gas shut-off valve can be of indirect and direct locking methods. In the first case, the electromagnet core is helped by the pressure of the working medium in the event of the shutter being activated. In the second, the shutter is moved only by the electromagnetic force acting on the rod.

Gas valves can do more than just protective function, but also distributional. In this sense, there are devices for different numbers of moves:

• Two way valves. These are the most common models of safety valves, having one inlet and one outlet. Their main function is to block the channel in any possible emergency situations.
• Three way valves. Control valves provide the ability to direct the flow of gas from an inlet between two outlets.
• Four-way valves can be installed in various complex systems, where there is a need to control energy flows through three different channels.

In addition to the above features of gas valve modifications, each specific device may have original design, different from the standard. Thus, some valves have internals specially manufactured to operate in aggressive conditions.

Installation Rules

To correctly install a solenoid valve on gas equipment, you must adhere to the following requirements:

• Valves are installed at the inlet of the line immediately after gas tap and filter element.
• The arrow on the device indicates the direction of energy flow.
• The valve position is only horizontal or vertical at an angle of 90 degrees.

Conclusion

All work on installation and maintenance of gas equipment can only be performed by qualified specialists gas service. This must be taken into account, otherwise incorrect work can lead to dire consequences.

Product Italian manufacturer, guarantee of uninterrupted operation of all types gas systems: water heating, heating and their variations. Provides regulation, blocking and direction of gas flows. Has manual cocking. The maximum values ​​are 6 Bar and 500 mBar. Power indicators are 9.0 W. There are versions with threads and flanges. Various models high-quality normally open gas valves.
If the product is used in conjunction with a gas detector, closing by alarm. It will take no more than one second to close.
Suitable for domestic and industrial needs (as a part of various gas consuming systems).

EVGNA versions

Operating principle of the EVGNA valve

When there is no voltage, the EVGNA valve is open, and when there is voltage and the stem is cocked, it closes. When the EVGNA valve is operating, for example, with a gas alarm, after a gas leak has occurred, the alarm relay contacts open, the valve is de-energized and shuts off the gas supply. Closing time less than 1 second. To open the valve, it is necessary to apply voltage to it, then cock it by pressing the cocking rod.

Technical characteristics of the gas shut-off valve normally open with manual cocking EVGNA

Overall dimensions of a normally open gas shut-off valve with manual cocking EVGNA

PRICES for valve EVGNA