RU79985U1 - WATER BOILER - Google Patents

Abstract

The boiler has convection channels of circular cross section located inside the circular heat exchanger. In the cavity of convective channels, metal turbulators are placed in the form of metal plates with semicircular protrusions. The height of the turbulator is 0.75-0.85 the height of the convective channel. The diameter of the protrusions of the turbulator is 0.7-0.8 of the inner diameter of the convective channel. The distance between the semicircular protrusions of the turbulator is 1.0-1.5 diameter of the protrusion of the turbulator. The heat exchanger of the boiler is divided into two parts by a vertical wall having round holes in its upper and lower parts. A twisted coil is located in the cavity between the vertical wall and the outer wall of the heat exchanger.

Description

The proposed boiler is designed for separate heating and hot water supply of apartments in residential multi-storey buildings and individual residential buildings, with natural and forced water circulation systems.

A known design of a domestic hot water boiler containing a furnace, placed in a water-cooled housing, equipped with a coil heat exchanger made of finned tubes, the heat exchanger located in the upper part of the housing and made of sections interconnected in series, in each of which the coil pipe is twisted by a single-thread screw lines, the pitch between which exceeds twice the diameter of the pipes (USSR author's certificate, No. 1196614 of April 16, 1990 (1)). A disadvantage of the known device is the complexity of manufacture and a small heat transfer area, which reduces the efficiency of heating water.

Known hot water boiler (patent for utility model No. 30946 dated 04.02.2003, (2)) which contains an airtight housing. A firebox is placed in the casing, over which a convective gas duct is made. In the furnace there are heat exchange elements in the form of transversely arranged water pipes assembled in vertical rows. The convective flue in its upper part is made in one piece with a smoke box into which a telescopic pipe is inserted, extending outside the buildings and having channels for supplying air to the furnace to the gas burner and for ejecting combustion products. In the lower part of the furnace, lateral screen horizontal pipes are installed. In the middle and upper parts of the furnace, horizontal (across the boiler) water pipes of different diameters are installed, which are connected to the screen pipes with the help of the front and rear water chambers of the boiler. The intensity of flushing pipes with a coolant is determined by the distance between the pipes in the same row and the distance between the pipes of two adjacent rows diagonally. The convective flue is made in a trapezoidal shape and in it the water pipes are arranged horizontally (across the boiler) in a checkerboard pattern and are also connected to the front and rear water chambers of the boiler. The trapezoidal arrangement of the pipes in the middle and upper parts of the furnace provides a cross-sectional area between the pipes of the first row greater than the cross-sectional area between the pipes of the last row by 1.5-2.5 times. In the rear part of the boiler, an additional channel (bypass) connected to the rear water chamber is made, in which a heat exchanger for hot water supply is located. The heat exchanger is made in the form of a twisted coil. The gas burner is connected to the boiler automation system. For ease of regulation, an automation system is installed in the front of the boiler.

In the known device, as a heat exchanger, horizontally arranged pipes are used, the number of which is at least 30 pieces. Therefore, boilers of this design have a high metal consumption. In the manufacture of a heat exchanger of this design, it is necessary to perform 60 or more welds, which significantly increases the complexity of the manufacture of the boiler and reduces its reliability during operation. In addition, the horizontal arrangement of the pipes does not provide uniform and efficient heat transfer between hot gases rising from the gas burner through the convective gas duct and the heat carrier located in the cavity of the heat exchanger. The use of an additional channel (bypass) with a heat exchanger also increases the metal consumption (weight) of the boiler, as well as its overall dimensions. In addition, the efficiency of the boiler in the hot water mode is reduced.

The closest analogue to the proposed hot water boiler is a hot water boiler (utility model patent No. 61013 of April 11, 2006 (3)). This boiler has an even number of vertical convective channels of trapezoidal shape divided by vertical walls into several flues. The channels are located inside a heat exchanger filled with a liquid coolant, such as water. The height of the convective channels is equal to the height of the heat exchanger, and the cross-sectional area of the lower base is 1.5-4.5 times larger than the cross-sectional area of the upper base of the convective channel. The gas burner is made two-section, with one of the sections working continuously, and the other has the ability to turn on if necessary through a separate locking element. Convective gas channels are installed directly above the two-section gas burner. The telescopic gas duct for the emission of combustion products is located inside the telescopic pipe for air supply and has a layer of thermal insulation on its surface. The coiled coil of the hot water circuit is installed directly in the cavity of the heat exchanger between the outer walls of the convective channels and the inner walls of the boiler body.

Boilers of known design have certain drawbacks, in particular convective channels of a trapezoidal shape are difficult to manufacture. Dividing the channel by vertical walls into flues significantly increases the metal consumption of the convective channel and the entire heat exchanger of the boiler, and also increases the amount of welding work. The experience of operating hot water boilers of known design has shown that the trapezoidal convective channels used in this boiler have certain disadvantages associated with uneven heating of the channel walls. This leads to local overheating of individual zones of the convective channel and, as a result, to local boiling of the coolant in superheated zones. In addition, in boilers of known design when you turn on the hot water circuit, the temperature of the coolant in the circuit decreases

heating and in order to raise the temperature in the heating circuit requires considerable time.

The purpose of the proposed utility model is to simplify the design of the boiler, reduce the complexity of manufacturing and, as a result, improve the operational characteristics of the boiler.

This goal is achieved in that the sealed hot water boiler has convective channels of circular cross section located inside the circular heat exchanger. In the cavity of convective channels, metal turbulators are placed in the form of metal plates with semicircular protrusions. The height of the turbulator is 0.75-0.85 the height of the convective channel. The diameter of the protrusions of the turbulator is 0.7-0.8 of the inner diameter of the convective channel. The distance between the semicircular protrusions of the turbulator is 1.0-1.5 diameter of the protrusion of the turbulator. The heat exchanger of the boiler is divided into two parts by a vertical wall having round holes in its upper and lower parts. A twisted coil is located in the cavity of the heat exchanger between the vertical wall and the outer wall of the heat exchanger.

Figure 1 shows a side view of the proposed hot water boiler. In the boiler there is a furnace 1. Firebox 1 in its upper part passes into convective channels 2 of circular cross section. Convective channels 2 externally are covered by a vertical wall 3 with round holes 4 in its upper and lower parts. In the lower part of the furnace 1, a gas burner 5 is installed, located above the bottom of the boiler body 6 and connected to the automation system 7. Several convective channels 2 are installed above the gas burner 5 (depending on the boiler output) 2. Combustion products through the smoke box 8 and the outlet 9 boiler shells are brought out of the premises. Through the pipe 10, air is supplied to the cavity between the boiler body 6 and the outer wall of the heat exchanger 11, from where air enters the gas burner 5. In the upper part of the boiler there is a twisted coil 12 of the hot water circuit. The coil 12 covers the convective channels 2 with its turns and is installed in the cavity between the convective channels 2 and the vertical wall 3, which is filled with a coolant (for example, water). Outside, all elements of the boiler are closed by a housing 6.

Figure 2 shows an example of a specific arrangement of convective channels in a heat exchanger (top view), where 2 vertical cylindrical convective channels. The number of channels in the heat exchanger determines the power of the boiler. In the cavities of the convective channels are turbulators 13.

Figure 3 shows an example of a specific embodiment of the turbulator 13 and its location in the cavity of the convective channel 2. The turbulator having a height h is located in the cavity of a cylindrical convective channel of height H and diameter D, and the height of the turbulator h is (0.75 ÷ 0.85 ) N, and the diameter of the protrusions of the turbulator d is (0.7 ÷ 0.8) D. The distance between the protrusions of the turbulator is (1.0 ÷ 1.5) d.

The boiler operates as follows.

During the operation of the gas burner 5, gas is burned in the furnace 1 and the rising hot combustion products enter the convective channels 2. The gas combustion products transfer part of their energy to the vertical walls of the convective channels 2, and these, in turn, pass through the walls of the convective channels 2 to the heat carrier in the space , bounded by the walls of the convection channels 2 and the outer wall of the heat exchanger 11. Having given part of their heat to the heat carrier, the combustion products reduce their volume. This leads to a decrease in the flow velocity of hot gases in the upper part of the convective channel and, as a result, to a deterioration in heat transfer in the upper part of the convective channel. The presence of metal turbulators 13 in the central part of the cylindrical convective channel helps to improve heat removal from the central part of the gas stream, where the temperature of the combustion products is maximum. With this design of the convective channel and turbulator, it is possible to ensure the maximum heat output from a unit surface of the convective channel, which determines the value of the boiler efficiency.

The products of combustion of gas fuel, giving part of their energy to the coolant, fall into the chimney box 8 and through the pipe 9 are removed outside the living room through an existing chimney.

At the same time, air enters the furnace through the pipe 10, which is fixed on the side surface of the boiler body 6. In the proposed design of the boiler, the organization of air supply is possible, both directly from the heated room, and from the street.

The presence of a certain amount of air used for combustion in the space between the wall of the heat exchanger 11 and the boiler body 6, improves the stability and stability of the gas burner.

The heating temperature of the coolant in the boiler is set before the boiler starts and is monitored by the automation system 7. When the coolant at the outlet of the boiler is heated to a temperature corresponding to the value set by the coolant temperature controller, the automation system 7 reduces the gas supply to the burners. After cooling the coolant in the heating system by a certain amount, the gas supply to the main burner is automatically restored.

If during the operation of the boiler from the water supply, water is piped to the hot water coil 12, then the water heated in the heat exchanger heats the coil 12 and will flow from it to the consumer’s hot water mixers. The volume in which the coolant is located in the heat exchanger is divided by a vertical wall 3 into two parts. The presence in the vertical wall 3 of cylindrical holes 4 helps to equalize the temperature of the coolant in the cavity of the heat exchanger during operation of the hot water circuit. it

occurs because in the presence of a vertical wall 3 there is an internal coolant circulation circuit.

Such a design of a hot water boiler reduces the complexity of manufacturing by simplifying the design of the heat exchanger. The use of cylindrical vertical convective channels, in combination with a cylindrical heat exchanger, simplifies the design of the boiler and reduces the amount of welding work performed in the manufacture of the heat exchanger. The minimum length of welds in the high temperature zone increases the reliability of the boiler of this design.

The use of cylindrical convective channels with metal turbulators, in the form of metal plates with semicircular protrusions, a height of 0.75-0.85 the height of the convective channel, the diameter of the protrusions of the turbulator 0.7-0.8 of the internal diameter of the convective and the distance between the semicircular protrusions of the turbulator 1.0 -1.5 diameter of the protrusion of the turbulator, can significantly improve the conditions of heat exchange between the hot products of combustion of gas fuel and the coolant. It is this design of the turbulator that ensures the efficient distribution of the gas flow in the convective channel and improves the heat transfer conditions. This leads to improved boiler performance. The parameters of the turbulator and convective channels were determined empirically. The test results are summarized in tables 1-3 (the efficiency of the boiler was determined by the value of the efficiency and the content of oxides in the combustion products).

The boiler heat exchanger, divided by a vertical wall into two parts, significantly increases the efficiency of the boiler in heating and hot water mode. The use of a heat exchanger separated by a vertical wall with holes in the upper and lower parts allows to improve the operational characteristics of the boiler, since the heat extraction by the hot water circuit does not affect the operation of the heating circuit.

In addition, the possibility of air intake for combustion both directly from the heated room and from the street significantly improves the operational and consumer characteristics of the proposed boiler design.

Information sources

1. Copyright certificate of the USSR, No. 1196614 of 04.16.90

1. Patent for utility model No. 30946 dated February 4, 2003.

2. Utility Model Patent No. 61013 of April 11, 2006.

Table 1 Quantitative signs Technical result Turbulator height The diameter of the protrusions The distance between the protrusions Boiler efficiency Oxide content in combustion products Less than 0.75 convective channel height Less than 0.7 convective duct internal diameter Less than 1.0 protrusion diameter Boiler efficiency less than 75% Not determined 1.0-1.5 protrusion diameter Boiler efficiency less than 78% Over 1.5 protrusion diameters Boiler efficiency less than 80% 0.7-0.8 of the internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 82% 1.0-1.5 protrusion diameter Boiler efficiency less than 82% Over 1.5 protrusion diameters Boiler efficiency less than 82% More than 0.8 internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 83% The content of carbon monoxide and nitrogen oxides in combustion products is higher than normal 1.0-1.5 protrusion diameter Boiler efficiency less than 84% Over 1.5 protrusion diameters Boiler efficiency less than 85%

table 2 Quantitative signs Technical result Turbulator height The diameter of the protrusions The distance between the protrusions Boiler efficiency Oxide content in combustion products 0.75-0.85 convective channel height Less than 0.7 convective duct internal diameter Less than 1.0 protrusion diameter Boiler efficiency less than 77% Not determined 1.0-1.5 protrusion diameter Boiler efficiency less than 79% Over 1.5 protrusion diameters Boiler efficiency less than 81% 0.7-0.8 of the internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 90% The content of carbon monoxide and nitrogen oxides in combustion products is higher than normal 1.0-1.5 protrusion diameter Boiler efficiency more than 90% The content of carbon monoxide and nitrogen oxides in the combustion products is within normal limits Over 1.5 protrusion diameters Boiler efficiency less than 90% The content of carbon monoxide and nitrogen oxides in combustion products is higher than normal More than 0.8 internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 85% The content of carbon monoxide and nitrogen oxides in combustion products is higher than normal 1.0-1.5 protrusion diameter Boiler efficiency less than 86% Over 1.5 protrusion diameters Boiler efficiency less than 86%

Table 3 Quantitative signs Technical result Turbulator height The diameter of the protrusions The distance between the protrusions Boiler efficiency The content of carbon monoxide and nitrogen oxides in combustion products is higher than normal Over 0.85 convective channel heights Less than 0.7 convective duct internal diameter Less than 1.0 protrusion diameter Boiler efficiency less than 77% 1.0-1.5 protrusion diameter Over 1.5 protrusion diameters 0.7-0.8 of the internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 90% 1.0-1.5 protrusion diameter Over 1.5 protrusion diameters More than 0.8 internal diameter of the convective channel Less than 1.0 protrusion diameter Boiler efficiency less than 85% 1.0-1.5 protrusion diameter Over 1.5 protrusion diameters

Claims (1)

A water boiler containing a sealed housing in which a furnace with a gas burner is located, a heat exchanger with a smoke box, inside which there are vertical convective channels, pipes for supplying air to the furnace to the gas burner and removal of combustion products, a twisted coil installed in the cavity of the heat exchanger, and an automation system connected to a gas burner, characterized in that the boiler has convective channels of circular cross section located inside the circular heat exchanger, in the cavities of which are placed metal turbulotors, in the form of metal plates with semicircular protrusions, the height of the turbulizer being 0.75-0.85 of the height of the convective channel, and the diameter of the protrusions is 0.7-0.8 of the internal diameter of the convective channel and the distance between the protrusions is 1.0- 1.5 diameters of the protrusion of the turbulator, the heat exchanger is divided into two parts by a vertical wall with round holes in its upper and lower parts, with a twisted coil located in the cavity between the vertical wall and the outer wall of the heat exchanger.