RU2822022C1 - Furnace air heater (fah) - Google Patents

Abstract

FIELD: heating equipment.

SUBSTANCE: present device relates to heating equipment, namely to air heating device. Furnace air heater includes external heat circuit, vertical furnace device made from heat-resistant steel, installation unit with a hatch and a grid for periodic ash removal, as a heat carrier in the air heater, compressed air is used with an initial start-up pressure of 3 kgf/cm², heated to the required temperature, which enters the heating system through the supply air pipe, air pressure and temperature are controlled by pressure gauge and thermometer, cooled air is returned for heating through the return air duct; the process is controlled visually or by means of a control unit. Application of the proposed air heater allows to expand the range of "small" heat power engineering means, using compressed air as a heat carrier, for solving household problems with heat supply of residential, civil and industrial facilities in natural conditions.

EFFECT: higher operational safety of heating systems, reduced operating costs and cost of heat, compared to traditional sources of heat energy.

1 cl, 10 dwg, 2 tbl

Description

This device relates to heating equipment, namely to an air-heating device (hereinafter referred to as the device), in which the air, compressed to a starting pressure of 3 kgf/cm2, with which the heating system is filled, is heated using a vertical pipe combustion device in which fuel is burned, to the required temperature and, due to convection, transfers the heat of heated air to the heating systems of residential, industrial and civil buildings. From the prior art, inventions are known that relate to the field of heat supply, including heating equipment in which, as a coolant, the following are used: 1) heated air obtained during the combustion of organic fuel (GB 220874, cl. E24D 5/08); 2) steam-water mixture (RU 2360184, class E24D 1/00); 3) steam-air mixture RU 2069821, class. 24D 1/00). All options with coolants have a common drawback - expensive thermal energy. The cheapest is the energy of recovered heat.

The purpose of the present invention is to reduce the cost of heat used for heating and household needs, to increase industrial and environmental safety during the operation of heat supply systems.

The problem to be solved by the stated technical solution is to expand the arsenal of technical means that have common features of similarity with heating equipment, the work of which is aimed at obtaining thermal energy from electric heating elements, at transferring thermal energy to the air flow coming from the heating system, to heat compressed air to the required temperature and return the heated compressed air, due to convection, to the heating systems of residential, industrial and civil buildings.

This problem is solved by creating a combustion air heater (hereinafter referred to as an air heater) which, using a vertical pipe combustion device in which fuel is burned, heats the compressed air coming from the heating system to the required temperature and returns the heated compressed air, due to convection, to the system heating of residential, industrial and civil buildings.

The air heater (Fig. 1) consists of three blocks connected to each other - an external thermal circuit (1), a vertical combustion device (2), an installation block with a hatch for periodically removing ash from the combustion device (3). The operation of the air heater is monitored using a control unit (KB), located separately. To reduce heat loss and ensure industrial safety of personnel, the external thermal circuit and the supply air duct are covered with thermal insulation made of mineral wool boards (4).

The external thermal circuit (1) consists of a steel cylinder with steel covers with heat-resistant sealant, bolts and screws (5) made of XN32T sheet steel with a thickness of 2 mm, insulation made of mineral wool plates (4), a ball valve (6) for connecting the supply air duct, heat-resistant pressure gauge (8) for pressure up to 12 kgf/cm2, thermometer (9) up to 600 degrees C, ball valve (6) for connecting the return air duct.

The vertical combustion device consists of a steel cylinder made of sheet steel grade XN32T with a thickness of 2 mm with an upper tube for removing gases released during fuel combustion and a lower tube used for periodic removal of ash from the combustion device, “welded” in a spiral to the height of the cylinder , a steel strip (10) made of sheet steel grade XN32T with a thickness of 1.5 mm, which directs air flows in a spiral upward at an angle of 30 degrees entering the external thermal circuit and at the same time serves as a stiffener for the steel cylinder, which is hermetically separated from external thermal circuit with asbestos sheet (11) 3 mm thick.

The installation block with a hatch (12) and a grate for periodic removal of ash from the combustion device consists of two covers (the upper one with holes for bolted connections, the lower one with a support “glass”), connected by six vertical stiffeners (13), arranged at 60 degrees in a circle , made of sheet steel grade XN32T with a thickness of 2 mm, with a hatch and an air intake hole (14).

The dimensions of the air heater, the diameters of the supply and return air pipes, the volume of the vertical combustion device are taken by calculation in accordance with the technical specifications. The air heater operates in manual control mode (if necessary, it can be retrofitted for control and operation in remote and automatic mode). While the air heater is operating, all three units are switched on simultaneously. The volume of fuel burned is determined by the temperature schedule of the air heater.

To operate the air heater, you can use various types of fuel and prefabricated internal or external gas exhaust pipes.

Fig. 10 shows a diagram of air heating, consisting of an air heater (Fig. 1), supply and return air pipes, heating devices, shut-off and control valves. Before turning on the electric heating elements of the air heater, the air heating system is pumped with air using a compressor to a starting pressure Рп=3 kgf/cm2. The pressure in the heating system is controlled by a pressure gauge (8). After equalizing the pressure in the system, the fuel is ignited. The quantity of fuel loaded at a time and the frequency of additional loading are determined by the temperature schedule of the air heater and are controlled by a temperature sensor (9). Air from the external thermal circuit, heated from the vertical combustion device, fills the heating devices through the supply air pipe and distribution pipelines and through which it releases heat into the heated space and returns through the return air pipe to the air heater for subsequent heating. To increase the heating area and increase the efficiency of heat transfer, the air supplied for heating moves from bottom to top, at an angle of 30 degrees, in a spiral, washing the outer thermal circuit of the air heater.

The invention is illustrated by drawings/sketches, which do not cover and, moreover, do not limit the entire scope of claims of this technical solution, but are only illustrative materials of a particular implementation case. Sketches of the invention:

In fig. 1. General view of the air heater.

In fig. 2. Section 1-1 in Fig. 1.

In fig. 3. Installation block in Fig. 1 and 2.

In fig. 4. Section 2-2 in Fig. 3.

In fig. 5. Section 3-3 in Fig. 3.

In fig. 6. Hatch with grille in Fig. 3 and 4.

In fig. 7. Lattice 4-4 in Fig. 6.

In fig. 8. Node 1 in Fig. 2.

In fig. 9. Node 2 in Fig. 2.

In fig. 10. Air heating scheme.

The advantage of the proposed technical solution is that compressed air is used as a coolant in the heating system, which significantly reduces the consequences of operational accidents, improves the environment, reduces the cost of operating the heating system and the cost of constructing heat supply systems.

The obtained technical result is based on the application of physical laws - “Archimedes”, “Boyle-Mariotte” (Isothermal process at T=const. P1/P2=V1/V2. For a given mass of gas at a constant temperature, the product of pressure and volume is a constant value . PV=const.), “Charles” (Isochoric process at V=const. T1/T2=V1/V2. The pressure of a given mass of gas is directly proportional to its absolute temperature), “Fourier” (The heat flux density is proportional to the temperature gradient, i.e. i.e. thermal conductivity coefficient is the heat flux transferred through a unit surface at unit values of the gradient temperature L = |q|/|gradt|).

The process of putting into operation an air heating system begins with filling the heating system with air, using a compressor, to the starting pressure Рп=3kgf/cm2. The pressure in the heating system is controlled by a pressure gauge. After equalizing the pressure in the system, the fuel is ignited. The quantity of fuel loaded at a time and the frequency of additional loading are carried out in accordance with the temperature schedule. Solid fuel is loaded into a vertical combustion device through the upper tube - to remove gases, liquid and gaseous, through the lower tube - to remove ash. The heated air rises vertically at a speed v=1-20 m/sec, expanding, displacing colder air, while the heated air, passing through the heating devices, gives off its heat to the environment. To calculate the technical data of the air heater, the following was used:

- diameter of the external thermal circuit - D (mm);

- diameter of the vertical combustion device - D (mm);

- height of the external thermal circuit -3D (mm);

- melting temperature of steel - 1500 C;

- thermal conductivity coefficient of steel - 45.4;

- coefficient of thermal expansion of steel at t=600 C=14.5;

For quantities that were used in the SI system, the following units of measurement are used:

for thermal conductivity - W/m*deg (L=[W/m*deg]);

for temperature - degree Kelvin (T=[K];

for heat flow (L=[L]=[W/m*deg];

for thermal expansion of the metal (K=[K]=[10 *1/deg];

for density - kg/m3 (q=[kg/m3]);

for volume - m3 (V=[m3]);

for area - m2 (S)=[m2]);

for pressure - pascal (p=[Pa]=[N/m3]).

The use of the proposed air heater allows us to expand the range of “small” heat power products that use compressed air as a coolant to solve everyday problems with heat supply to residential, civil and industrial facilities, in natural conditions. This achieves the effect of increasing the operational safety of heating systems, reducing operating costs and the cost of heat, in comparison with the traditional sources of thermal energy used.

Information sources:

* Patent RU 2069821, E 24D 1/00, 11/27/1986 (prototype);

* Patent GB 2208741, E24D 5/08, 07/20/2003;

** Baskakov A.P. “Heat engineering”. Moscow. "Energoatomizdaniye" 1991.

*** M.I.Bat, G.Yu. Dzhanilidze. Theoretical Mechanics, - M.: Science. 1967

**** SNiP 2.04.05.91; SNiP 41-01-2003; GOST 12766.1-90; GOST1173-2006; GOST 24982-81; GOST 5632-72.

Claims (1)

A combustion air heater, including an external thermal circuit made of heat-resistant steel, a vertical combustion device, an installation block with a hatch and a grate for periodic ash removal; compressed air with an initial starting pressure of 3 kgf/cm ² , heated to the required temperature, is used as a coolant in the air heater , which enters the heating system through the supply air pipe, the air pressure and temperature are controlled by a pressure gauge and thermometer, the cooled air is returned for heating through the return air pipe, the process is monitored visually or using a control unit.