Gate valve: what is it and how to use it?

If you translate word for word from German, the gate is a shutter or a shutter. The simplest design of this device was used by our distant ancestors. It can be found wherever there is stove heating - this is a retractable damper, which is located in the oven chimney. Use such a latch to ensure that warm air does not leave the heated room through the chimney .

If you switch to a scientific language, the definition will sound like this: a gate is a shut-off and regulating equipment with internal insulation for chimneys, air ducts, industrial air purification and ventilation systems, capable of operating at high temperatures. Its main element is a metal sheet moving along the guiding corners or inside the slot pocket. Depending on the application, a coating is applied to the shutter to protect it from the action of the corrosive medium.

Areas of use

The gate is a metal plate (or wedge), which, when the flow is blocked, can separate the mechanical inclusions passing through the damper. Due to this, such closures are used on pipelines with different media: dry, loose mixtures, heavy oil products, various gases and others.

Like most locking devices, the gates can have a manual control system, either electric or hydraulic. This type of shutter in our time is most often used in the design of chimneys and in ventilation systems.

A significant quality of the gate is that in the open state it is completely removed from the body of the pipe, creating the least resistance to the remains of the exhaust gas. Thanks to this, the gates are actively used in obtaining a high vacuum.

Types of gate valves

There are two types of dampers: rotary and horizontal. The first is also called the throttle. This is a gate of the classical type, which is a plate that is fixed on a rotating axis. The axis is located inside the chimney or branch pipe. Rotary slide is less reliable, so it is only used if it is not constructively possible to install a horizontal one.

The horizontal sliding slide allows to regulate the process by changing the sectional area of the chimney channel due to the horizontal extension of the plate. Most often used in steel and brick chimneys. It is more reliable, and therefore, if there is a technical possibility, a sliding slide is installed. The plate itself of such a damper is perforated or has propyl. This is necessary to ensure that the gate does not obscure the channel completely - these are the requirements of fire safety.

Functions of the gate

Its functions differ depending on the field of application. If the gate is used in the pipeline system as a stop valve, it will function as a restriction of the movement of the liquid (loose mixtures). Such a gate is also called a flip-flop.

In the ventilation system, the gate acts as a device that regulates the air flow. It is possible to move the flap forward and back, thereby changing the flow of air passing through the structure, blocking partially or completely the flow path. Such a gate is called regulating.

In the chimney the damper is used as a damper of the regulator, which allows to cover partially or completely the section of the smoke channel, which allows to reduce the heat loss inside the room after the firebox.

The damper for the chimney performs one more function - the thrust regulator, that is, it acts as a control damper along the smoke path. Here the principle operates: the more the section of the chimney channel is blocked, the less air comes in and the thrust decreases. Conversely, the larger the gate is open, the more air and thrust the stronger, the burning process is much more intense and faster.

Constructive specificity

The design of the gate is influenced by many factors: the temperature of the transported medium, the shape of the pipe section, the conditions of the passage, etc. The basis of the design is a metal sheet of different thickness, moving in a slit pocket or along the guiding corners.

There are different types of slats for different reasons. Isolate shut-off and flaps, limiting the movement of the flow. According to the principle of action, the slats are classified according to the type of drive: manual, pneumatic, hydraulic, electrical, etc., and by design, they distinguish straight and oblique.

Direct slate is in appearance a classic flapper. It is used in the forced-air ventilation system. Slanting slat is used in industrial aspiration and pneumatic conveying systems. "Skew" is called because of the installation at 45 degrees, and not as normal - perpendicular, which allows a very accurate and smoothly dose air flow.

A very important point is what material is made of the gate. Depending on where the device is applied, it can be made of stainless, chrome or alloy steel.

Features of the installation in the chimney

In the chimney, the gate is usually installed in two ways. First - the device is connected to the other elements of the chimney without additional fasteners. This method was called "pipe in the pipe."

In the second variant, the gate is located directly in the furnace or in the outlet branch pipe as a separate element, that is, the damper is built directly into the structure. With this design, the gate is installed at a height of not more than one meter, that is, close enough to the heating device itself. This ensures easy control of the valve.

Installation in the ventilation system

Ventilation vanes are usually installed at the fan output. This is the most common place of installation. If the damper and the fan are installed together, this design is called a starter. The gate acts as a protective plug to prevent the engine from overheating when the fan starts. The fan must be started only when the slate is closed, since a large load is applied to the electric motor in the open state, which can lead to a breakdown of the system.

When installing the gate, you need to take into account the shortcomings of this device. For example, if the chimney is straight, then the presence of a bolt will make it harder to clean the furnace from soot. And if the gate has no automatic opening function in the ventilation system, it is desirable to equip the fan with a frequency converter or a soft starter.