RU213381U1 - CONVECTION GAS BOILER AIR INLET REGULATOR - Google Patents

Abstract

The utility model relates to the field of thermal power engineering, in particular to convection-type boilers, combustion air supply devices, and can be used in decentralized and autonomous heating and hot water supply systems for buildings. The technical result is achieved by placing an area-adjustable valve for supplying air to the boiler burner. Adjustment is carried out at the boiler location, with specific technical characteristics of the chimneys and air intake ducts, by setting the required valve position according to the color of the combustion flame and the readings of portable gas analyzers. The regulation of the cross-sectional area of the valve is changed by means of a linear servo drive with a stepping motor. The fastening of the valve actuator is made with the possibility of adjusting its initial position. The possibility of adjusting the position is brought to the outer surface of the boiler body. The initial adjustment of the position of the valve servomotor is carried out once during installation and commissioning of the boiler and does not require repeated changes. After adjustment, the position of the adjusting servo is fixed. The position of the air supply valve depends on the power of the boiler burner. The possibility of changing the air supply for the operation of the boiler at different power allows you to optimize the combustion modes. The proposed utility model, compared with the prototype and other known technical solutions, has the advantage of a higher energy efficiency ratio and reduces greenhouse gas emissions arising from the operation of boilers for heating and hot water supply systems. 2 w.p. f-ly, 1 ill.

Description

Field of technology to which the utility model belongs

The utility model relates to the field of thermal power engineering, in particular to convection-type boilers, combustion air supply devices, and can be used in decentralized and autonomous heating and hot water supply systems for buildings.

State of the art

An outdoor boiler is known, containing a hydrothermal insulated housing with a heat exchanger placed in it with a direct and return lines, a burner, a chimney base, a circulation pump, while it is additionally equipped with an automatic valve with a constantly open nozzle, and the circulation pump is equipped with supply and suction pipes and is located along the return line, and an automatic valve with a permanently open nozzle is installed between the connections of the nozzles on the return line (see patent RU No. 2436018, IPC F24H 1/00, dated 06/07/2010).

The disadvantage of this boiler is low reliability, low coefficient of energy efficiency, large size, the intake of air necessary for combustion comes directly from the atmosphere through constantly open air intake channels.

Known outdoor condensing boiler, containing a hydrothermal insulated housing, inside which there is a gas burner, a fire-tube heat exchanger with direct and return lines, a coaxial chimney connected to a chimney, additionally equipped with a condensing heat exchanger and a centrifugal fan, while the coaxial chimney with a condensing heat exchanger is installed behind the fire-tube a heat exchanger at the base of the chimney, and in the upper part of the hydrothermal insulation housing, behind the fire-tube heat exchanger, a centrifugal fan is installed with the ability to overcome additional resistance to the movement of flue gases in the coaxial chimney (see patent RU No. 2449225, IPC F24H 1/00, published on April 27, 2012 .).

The disadvantage of this design is the large size and complexity of maintenance, high cost, air intake occurs through constantly open air channels.

The boiler designs presented above cannot be used for apartment heating and hot water supply in multi-storey buildings or for small areas due to their size.

Known outdoor boiler, containing a heat-insulated housing with a heat exchanger placed in it with direct and return lines, a burner, an automatic coolant replenishment unit, characterized in that an air intake channel for the formation of a combustible mixture and a channel for removing combustion products are made in a heat-insulated soundproof housing, equipped with shut-off two-position valves, having electromagnetic actuators that ensure tightness during pauses in the operation of the boiler and in case of any gusts of wind (see utility model patent RU No. 199017, IPC F24H 1/10, F24H 1/08 of 08/07/2020).

However, when using convection-type boilers, the specific conditions for the placement of boilers and the design of chimneys are often not taken into account during operation. It is necessary to adjust the volume of air intake to form the optimal gas-air mixture directly at the boiler location. In the event of a non-optimal ratio of combustible gas and air in the gas-air mixture for the operation of a convection gas boiler, it is possible to increase CO and NOx greenhouse gas emissions and reduce the efficiency of the boiler.

From open sources (Toropov A.L., "Wall-mounted gas boilers of autonomous heating systems. History of creation. Main elements. Classification. Part 1. Convection wall-mounted gas boilers, textbook." - M .: Publishing house of the Academy of Natural Sciences, 2020. - 60 pp. ISBN 978-5-91327-630-8 DOI 10. 17513/pr.411) it is known that convection gas boilers are designed to operate without the formation of flue gas condensate on the heat exchanger. The main elements of a convection gas boiler are: a primary heat exchanger, an atmospheric gas burner, a smoke exhaust fan with a constant speed asynchronous motor, a hydraulic flow distribution group, a secondary heat exchanger, a boiler control system unit, a chimney impinging combustion products and air supply channels necessary for combustion . From open sources (Toropov A.L., "Wall-mounted gas boilers of autonomous heating systems. History of creation. Main elements. Classification. Part 1. Convection wall-mounted gas boilers, textbook." - M .: Publishing house of the Academy of Natural Sciences, 2020. - 60 pp. ISBN 978-5-91327-630-8 DOI 10. 17513/pr.411) it is known that the fan operation of the smoke exhaust system of a convection boiler occurs at a constant rotor speed and does not depend on the specific installation conditions of the boiler. The possibility of using boilers, indicated by the manufacturer, is determined by the minimum and maximum values of the lengths of the chimneys, the minimum and maximum power of the boiler in all cases of operation, the performance of the smoke exhaust ventilation unit does not change, since this is not provided for by the design.

Since the fan of the smoke exhaust system of convection boilers operates at a constant speed, and the chimneys and combustion air supply channels depend on the specific object in which the boiler is located, and the required power of the boiler changes several times, then at a fixed fan speed, an inefficient, identical throughout the range of changes in thermal power, mixture formation of an air-gas combustible mixture used in combustion (Toropov A.L., “Wall-mounted gas boilers of autonomous heating systems. History of creation. Main elements. Classification. Part 2. Condensing wall-mounted gas boilers. - M .: Publishing House of the Academy of Natural Sciences, 2020. - 68 pp. ISBN 978-5-91327-642-1 DOI 10. 17513/project 417).

Inefficient mixture formation leads to significant greenhouse gas emissions and loss of efficiency of the thermal power plant. Regulation of the volumes of air required for combustion is possible only at the boiler site, since only in this case the characteristics of specific chimneys and air supply channels are known. In technical essence, the closest to the proposed utility model is a double-circuit wall-mounted gas boiler (see patent RU No. 202243, F24H 1/08 (2020.08); F23N 3/02 (2020.08); F23L 1/00 (2020.08), dated 11.09. 2020).

Convection-type boiler with a closed combustion chamber, consisting of a burner, a heat exchanger, a flue gas removal fan equipped with an asynchronous electric motor with a constant rotor speed, an intermediate chamber for air intake from separate air channels, with air entering the closed combustion chamber through an area-adjustable valve section with a mechanism for adjusting the valve flow section, brought to the outer casing of the boiler.

The disadvantage of the proposed design is that at different ambient temperatures, different power of the gas boiler is needed to maintain the temperature in the room. The change in power in convection gas boilers occurs due to a change in the power of the gas burner (the amount of combustible gas supplied). More oxygen is needed to burn more gas. In convection boilers, fans with a constant rotor speed are used. Thus, the amount of air supplied for combustion is the same for the entire power range. When operating at low power, air is supplied with a significant excess of air, which significantly reduces the energy efficiency of the boiler, since the mixture of combustible gas with air becomes depleted.

Disclosure of the essence of the utility model

The objective of the proposed utility model is to develop a device that regulates the volume of air entering the boiler from the air intake channels. This adjustment can be carried out by changing the size of the flow area of the internal channels of the boiler, which provide air supply to the combustion zone of the gas-air mixture.

The air intake comes from separate air channels. An intermediate chamber is placed in the boiler structure to provide this air intake option.

The technical result is achieved by placing an area-adjustable valve for supplying air to the boiler burner. Adjustment is carried out at the boiler location, with specific technical characteristics of the chimneys and air intake ducts, by setting the required valve position according to the color of the combustion flame and the readings of portable gas analyzers. The control valve is equipped with a stem, a stepper motor with linear movement is attached to the stem. The stepper motor is fixed on the top of the boiler, and the mounting mechanism allows adjustment of the position along the axis of the control valve. Adjustment of the position of the stepper motor is brought to the outer surface of the boiler body, which allows it to be carried out without opening the boiler body. Adjustment is carried out once during installation and commissioning of the boiler and does not require repeated changes. After adjustment, the position of the stepper motor is fixed. The valve position is fixed for the variant of the maximum power of the gas boiler. For boiler operation options at lower power, the valve stem can be moved using a stepper motor. The position of the stem is related to the power of the boiler. Thus, it is possible to set the initial position of the stepper electric motor of the rod position drive depending on the resistance of the chimneys of a particular object where the boiler is located (performed once when setting the boiler operation) and adjust the position of the air supply valve stem depending on the boiler power.

Brief description of the drawings

The figure 1 shows a diagram of a convection-type boiler with a closed combustion chamber. Implementation of the utility model.

A convection-type boiler with a closed combustion chamber consists of a burner 1, into which combustible gas enters under pressure, a heat exchanger 2, into which cold water (heat carrier) enters and heated water (heat carrier) exits, combustion products (flue gases) are removed using a fan 3 equipped with an asynchronous type electric motor with a constant rotor speed. The air required for combustion enters Zone I from separate air supply channels, the direction is indicated by arrows B. From Zone I, the air enters Zone II of the closed chamber through an opening with a valve 4, the flow section of which is determined by a linear movement mechanism with a stepper motor 5. Adjustment 6 of the position of the stepper motor 5 is placed on the outer surface of the boiler, which allows you to adjust without disassembling it.

From Zone II, air enters burner zone 1, mixes with combustible gas, ignites and generates thermal energy during combustion. The optimal ratio of air and combustible gas volumes is determined by the set section of the adjustable valve 4 using a linear movement mechanism with a stepping electric motor 5, which is mounted once when setting the boiler operation at a specific object according to the color of the combustion flame and the readings of portable gas analyzers for operation at maximum power.

The proposed utility model, in comparison with the prototype and other known technical solutions, has the advantage of a higher energy efficiency coefficient, since this indicator depends on the correct ratio of combustible gas and air volumes, which are unique at each facility. It is the possibility of adjusting the volume of air intake that makes it possible to achieve maximum results in the efficiency of combustion of the gas-air mixture and minimize greenhouse gas emissions throughout the entire range of changes in the power of the gas burner of a convection boiler.

Claims (3)

1. A convection-type boiler with a closed combustion chamber, consisting of a burner, a heat exchanger, a flue gas removal fan equipped with an asynchronous electric motor with a constant rotor speed, an intermediate chamber for air intake from separate air channels, characterized in that air enters from the intermediate chamber into a closed combustion chamber through an area-adjustable valve section, the size of the flow section of which is changed using a linear servo drive with a stepper electric motor. 2. Boiler according to claim 1, characterized in that a linear servo drive with a stepper motor is attached to the boiler body. 3. Boiler according to claim 1, characterized in that the mechanism for adjusting the mounting of the servomotor is displayed on the outer casing of the boiler.

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