If translated literally from German, a gate is a damper or shutter. The simplest design of such a device was used by our distant ancestors. It can be found everywhere where stove heating is still available – this is a retractable damper that is located in the stove chimney. They use such a valve so that warm air does not escape from the heated room through the chimney.
If we switch to scientific language, the definition will sound like this: a damper is a shut-off and control 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 that moves along the guide corners or inside the slotted pocket. Depending on the application, the valve is coated to protect it from aggressive environments.
Applications
Shiber is a metal plate (or wedge), which, when the flow is blocked, can separate mechanical inclusions passing through the damper. Due to this, such valves are used on pipelines with different media: dry, loose mixtures, heavyoil products, various gases and others.
Like most locking devices, gate valves can be operated manually or electrically or hydraulically. This type of shutter is most often used in the construction of chimneys and ventilation systems in our time.
A significant quality of the gate is that in the open state it is completely removed from the pipe body, creating the least resistance to the remnants of the outgoing gas. Due to this, gates are actively used when obtaining a high vacuum.
Types of gates
There are two types of dampers: rotary and horizontal dampers. The first is also called the throttle valve. This is a classic type gate, which is a plate, which is fixed on a rotating axis. The axis is located inside the chimney or nozzle. The rotary gate is less reliable, therefore it is used only if it is structurally impossible to install a horizontal one.
The horizontal retractable damper allows you to control 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, a retractable gate is installed. The plate of such a damper itself is perforated or has a cut. This is necessary so that the gate does not completely cover the channel - these are the requirements of fire safety.
Functionsslide gate
Its functions vary depending on the application. If the gate is used in the pipeline system as a shut-off valve, then it will perform the function of restricting the movement of liquid (loose mixtures). Such a gate is also called a flip gate.
In the ventilation system, the damper plays the role of a device that regulates the air flow. You can move the damper back and forth, thereby changing the flow rate of air passing through the structure, partially or completely blocking the flow path. Such a gate is called a regulating gate.
In the chimney, the damper is used as a regulator damper, which allows partially or completely blocking the cross section of the smoke channel, which reduces heat loss inside the room after the firebox.
The chimney damper performs another function - a draft regulator, that is, it acts as a control damper along the smoke path. The principle applies here: the more the section of the chimney channel is blocked, the less air enters, and the draft decreases. And vice versa, the more the gate is open, the more air and the stronger the draft, the combustion process is much more intense and faster.
Design specifics
Many factors influence the design of the gate: the temperature of the transported medium, the shape of the pipe section, passage conditions, etc. The basis of the design is a metal sheet of different thickness, moving in a slotted pocket or along the guide corners.
Gate valves differ for various reasons. Allocate shut-off and toggle gates that restrict the movement of the flow. According to the principle of operation of the gateclassified according to the type of drive: manual, pneumatic, hydraulic, electric, etc., and according to the type of construction, straight and oblique are distinguished.
A straight gate is a classic damper in appearance. It is used in the forced-air supply and exhaust ventilation system. The oblique gate is used in systems of industrial aspiration and pneumotransport. It is called "oblique" because of the installation at 45 degrees, and not as usual - perpendicularly, which allows you to very accurately and smoothly dose the air flow.
A very important point is what material the gate is made of. Depending on where the device will be used, it can be made of stainless, chrome or alloy steel.
Features of installation in the chimney
The chimney damper is usually installed in two ways. First - the device is connected to the rest of the chimney without additional fasteners. This method is called "pipe to pipe".
In the second version, the damper is located directly in the furnace or in the outlet 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 no more than one meter, that is, close enough to the heater itself. This makes the valve easy to operate.
Installation in a ventilation system
Ventilation dampers are usually installed at the outlet of the fan. This is the most common mounting location. If the damper andthe fan is installed together, this design is called the starting gate. The valve here acts as a protective plug that prevents the motor from overheating when the fan is started. 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, the disadvantages of this device must also be taken into account. For example, if the chimney is straight, then the presence of a valve will complicate the cleaning of the furnace from soot. And if the damper in the ventilation system does not have an automatic opening function, it is advisable to equip the fan with a frequency converter or a soft starter.
