If you translate literally from German, the gate is a flap or shutter. The very simplest design of such a 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 furnace chimney. Such a valve is used so that warm air does not come out of 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 control equipment with internal insulation for chimneys, air ducts, industrial air cleaning systems and ventilation, capable of operating at high temperatures. Its main element is a metal sheet that moves along guide corners or inside a slot pocket. Depending on the application, the shutter is coated to protect it from the action of aggressive media.
Areas of use
The gate is a metal plate (or wedge) that, when shutting off the flow, can separate the mechanical inclusions passing through the flap. Due to this, similar closures are used on pipelines with different environments: dry, loose mixes, heavy oil products, various gases and others.
Like most locking devices, gates can have a manual control system or an electric or hydraulic actuator. This type of shutter in our time is most often used in the construction of chimneys and ventilation systems.
The significant quality of the gate is that in the open state it is completely removed from the pipe body, creating the least resistance to residues of the outgoing gas. Due to this, the gates are actively used in obtaining high vacuum.
Types of gates
There are two types of dampers: the rotary gate and horizontal. The first is called the throttle. This is a gate of the classical type, which is a plate that is attached to a rotating axis. The axis is located inside the chimney or pipe. The rotary gate is less reliable, therefore, it is used only if it is not possible to install the horizontal constructively.
Horizontal sliding gate allows you to adjust the process by changing the cross-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, install retractable gate. The plate of such a valve is perforated or has a cut. This is necessary so that the gate does not completely block the channel - these are the requirements for fire safety.
Its functions vary by application. If the gate is used in the pipeline system as a shut-off valve, it will perform the function of restricting the movement of fluid (bulk mixtures). This gate is also called flip.
In the ventilation system, the gate plays the role of a device that regulates air flow. You can move the valve back and forth, thereby changing the flow rate of air passing through the structure, blocking in part or all the flow. This gate is called regulatory.
In the chimney, the gate is used as a damper for the regulator, which allows to partially or completely block the cross section of the smoke channel, which reduces the heat loss inside the room after the firebox.
The gate for the chimney performs another function - the regulator of thrust, that is, acts as a regulating valve along the smoke. Here the principle applies: the more blocked the cross-section of the chimney channel, the less air enters, and the draft decreases. Conversely, the more the gate is open, the more air and thrust is stronger, the combustion process is much more intense and faster.
The design of the gate is influenced by many factors: the temperature of the transported medium, the shape of the pipe section, the passage conditions, etc. The basis of the design is a metal sheet of different thickness, moving in a slot pocket or along guide angles.
Shibery differ on different grounds. Allocate shut-off and flip valves, limiting the flow. By the principle of operation, the gates are classified according to the type of drive: manual, pneumatic, hydraulic, electric, etc., and by type of construction they distinguish between straight and oblique.
A straight gate is a classic flap in appearance. It is used in the forced-air ventilation system. The slanting gate is used in industrial aspiration and pneumatic transport systems. "Slanting" it is called because of the installation under 45 degrees, and not as usual - perpendicular, which allows for very accurate and smooth metering of air flow.
A very important point is the material of which the gate is made. Depending on where the device is applied, it can be made of stainless, chrome or alloyed steel.
Features of installation in the chimney
In the chimney gate is usually installed in two ways. The first is that the device is connected to the rest of the chimney elements without additional fasteners. This method is called "pipe in pipe".
In the second embodiment, the gate is located directly in the furnace or in the outlet nozzle as a separate element, that is, the valve is built directly into the design. With this design, the gate is installed at a height of not more than one meter, that is, close enough to the heater itself. This provides ease of valve control.
Installation in the ventilation system
Ventilation dampers are usually installed at the fan outlet. This is the most common installation site. If the damper and fan are installed together, this design is called the starting gate. The valve here serves as a protective plug to prevent the engine from overheating when the fan starts. It is necessary to start the fan operation only when the gate is closed, since in the open state a large load is applied to the electric motor, which can lead to system failure.
When installing the gate must take into account the disadvantages of this device. For example, if the chimney is straight, the presence of a valve will complicate the cleaning of the furnace from soot. And if the gate in the ventilation system does not have an automatic opening function, it is desirable to equip the fan with a frequency converter or soft starter.