JP5405794B2 - Furnace pressure control device and furnace pressure control method - Google Patents

Description

  The present invention relates to a furnace pressure control device and a furnace pressure control method for controlling the pressure of a furnace such as an industrial furnace.

  Conventionally, in order to control the pressure of a furnace such as an industrial furnace, for example, in those shown in Patent Document 1, Patent Document 2, and Patent Document 3, a furnace pressure gauge for measuring pressure is provided in the furnace, A pressure control air inflow passage having a control valve is connected to the furnace, and a controller for driving the control valve is provided. Based on a measurement signal of the furnace pressure gauge, the control valve is controlled to control the pressure control air flow path. The pressure in the furnace was controlled by adjusting the flow rate of the control air that flows in through the furnace.

Further, in Patent Document 4, a furnace pressure gauge for measuring pressure is provided in the furnace, an exhaust flue for discharging exhaust gas in the furnace is connected to the furnace, a damper is provided in the exhaust flue, and the furnace Based on the measurement signal of the pressure gauge, the pressure inside the furnace was controlled by controlling the damper.
Japanese Patent Application No. 6-102073 JP 2001-82737 A JP 2002-220620 A Japanese Patent Publication No.61-34048

  In the above conventional example, it was necessary to provide a furnace pressure gauge in the furnace, an electric control valve and a controller, and a damper in the exhaust flue. For this reason, the number of parts increases, and control valves, controllers, dampers, etc. have moving parts and are exposed to high temperatures, so they are inferior in reliability and durability and need to be adjusted. There was the fault that there was.

The present invention has been made in view of the above points, and the object of the present invention is that a furnace pressure gauge, a control valve, a controller and a damper are not required, the number of parts is small, and it is directly exposed to a high temperature in the furnace. An object of the present invention is to provide a furnace pressure control device and a furnace pressure control method that have no parts, have few movable parts, are excellent in reliability and durability, do not require adjustment, require no electric power, and are inexpensive.

  In order to solve the above-mentioned problems, the invention according to claim 1 is provided with a combustion device 2 as a heating means in a furnace 1 and an exhaust flue 3 connected thereto, and a pressure control air flow path 4 connected to the exhaust flue 3. A pressure equalizing valve 5 is provided in the pressure control air flow path 4, and the pressure equalizing valve 5 is connected to a primary chamber 52 partitioned by a diaphragm 51 to which a valve body 6 is connected. The primary chamber 52 and the secondary chamber 53 have introduction holes 52 a and 53 a that communicate with the inside and the outside, respectively, and are formed in the introduction hole 52 a of the primary chamber 52 and the furnace 1 and communicate with the inside and outside of the furnace 1. The pressure guiding tube 13 is connected between the outlet hole and the introduction hole 53a of the secondary chamber 53 and the space having the target pressure gas are communicated, and the pressure of the primary chamber 52 is compared with the pressure of the secondary chamber 53. The higher the value, the smaller the opening of the air flow path 4 for suppression. .

  By using the pressure equalizing valve 5 as described above, unlike a conventional example, a furnace pressure gauge, a control valve, a controller and a damper are unnecessary, the number of parts can be reduced, and direct exposure to the high temperature in the furnace 1 can be achieved. There are no parts to be used, and since there are only a few movable parts such as the diaphragm 51 (and the valve body 6), it is excellent in reliability and durability, and adjustment is not particularly required. It becomes possible.

The invention according to claim 2 is a furnace pressure control method for a furnace 1 provided with a combustion device 2 as a heating means and having an exhaust flue 3 connected thereto. 4 and a pressure equalizing valve 5 having a primary chamber 52 and a secondary chamber 53 partitioned by a diaphragm 51 are provided in the pressure control air flow path 4, and the gas in the furnace 1 is supplied to the primary chamber 52. introduction to with the pressure in the primary chamber 52 to the same as the furnace pressure, the target pressure of the pressure in the secondary chamber 53 by introducing a gas target pressure in the secondary chamber 53, compared to the pressure in the secondary chamber 53 Then, the higher the pressure in the primary chamber 52, the smaller the opening degree of the suppression air passage 4 is adjusted to control the flow rate of the suppression air, and the furnace pressure is set as the target pressure. It is.

  By using the pressure equalizing valve 5 as described above, unlike a conventional example, a furnace pressure gauge, a control valve, a controller, and a damper are unnecessary, and the number of parts can be reduced. There are no parts that are directly exposed to high temperatures, and since there are only a few movable parts such as the diaphragm 51 (and the valve body 6), it is excellent in reliability and durability, and no adjustment is required, and no electric power is required. Can be performed.

  In the present invention, the furnace pressure can be kept constant easily and inexpensively with a simple configuration.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  Examples of the furnace 1 include various industrial furnaces such as a heating furnace and a heat treatment furnace including a forging furnace, but other furnaces may be used.

  The furnace 1 has a furnace inner space surrounded by a furnace wall 11, a hearth, and a furnace ceiling, and is provided with a door that can be opened and closed by forming an entrance / exit in the furnace wall 11. In addition, an exhaust port 12 is provided in the furnace wall 11 or the furnace ceiling, and a duct 30, the inside of which forms the exhaust flue 3, is connected to the exhaust port 12. And the combustion apparatus 2 as a heating means is provided in the furnace wall 11. FIG. Reference numeral 20 in the figure is a blower for sending air to the combustion device 2, and reference numeral 31 is an induction fan provided in the exhaust flue 3.

  In the present invention, in the furnace 1 to which the exhaust flue 3 is connected, the air for controlling pressure is introduced into the exhaust flue 3 in order to keep the pressure in the furnace 1 properly. In addition to connecting the downstream end of the pressure control air pipe 40, the inside of which is the pressure control air flow path 4, the pressure equalizing valve 5 is provided in the pressure control air pipe 40. In addition, the upstream end portion of the suppression air passage 4 is open to the atmosphere in the present embodiment.

  As shown in FIG. 2, the pressure equalizing valve 5 is provided in a main body 50 having an outer casing 50 a, a valve body 6 protruding from the main body 50, and the pressure-control air flow path 4 and is opened by the valve body 6. The main body is constituted by the valve opening 42 whose degree is adjusted.

  The main body 50 has a primary chamber 52 and a secondary chamber 53 which are partitioned by a diaphragm 51 inside a sealed interior, and is introduced to communicate with the respective wall portions of the primary chamber 52 and the secondary chamber 53 from inside and outside. The holes 52a and 53a are formed so as to penetrate therethrough. The pressure guiding tube 13 is connected between the introduction hole 52 a formed in the wall portion of the primary chamber 52 and the lead-out hole formed in the furnace wall 11 of the furnace 1 and communicating with the inside and outside of the furnace 1. By connecting the pressure guiding tube 13, the primary chamber 52 communicates with the space in the furnace, and the gas in the furnace 1 can be introduced into the primary chamber 52 to make the pressure in the primary chamber 52 substantially the same as the furnace pressure. It becomes.

  The introduction hole 53a of the secondary chamber 53 communicates with a space having a gas having a target pressure, and a flow path communicating with the space is connected to the introduction hole 53a of the secondary chamber 53 or a gas having a target pressure. In the atmosphere, the secondary chamber 53 is opened to the atmosphere through the introduction hole 53a. By introducing a gas having a target pressure into the secondary chamber 53, the atmospheric pressure in the secondary chamber 53 can be set as the target pressure.

  The above-described valve body 6 is connected to the diaphragm 51. More specifically, the valve body 6 has a base end portion connected to the diaphragm 51 and an intermediate portion protruding outside the outer shell casing 50a through an insertion hole 50b formed in the wall portion of the outer shell casing 50a. Is a valve portion 61 for adjusting the opening degree of the valve opening 42.

  A through hole 41 is formed in a part of the side wall of the pressure suppression air pipe 40, and an outer casing 50 a is attached so that the through hole 41 communicates with the insertion hole 50 b of the outer casing of the pressure equalizing valve 5. The through hole 41 of the air suppression pressure tube 40 and the insertion hole 50b of the outer casing have substantially the same cross-sectional area in a cross section perpendicular to the moving direction of the valve body 6, and when the valve body 6 is inserted, the gap is closed. The gas does not flow in and out through the through hole 41 and the insertion hole 50b. And the said valve opening 42 is provided in the position corresponding to the valve part 61 inserted through the through-hole 41 of the air pipe 40 for pressure suppression. The valve opening 42 is provided in the suppression air pipe 40 as a throttled aperture for reducing the flow passage area of the suppression air passage 4. In this embodiment, the valve opening 42 is perpendicular to the suppression air passage 4. The valve opening 42 is also provided so as to face the direction perpendicular to the air flow path 4 for pressure control in accordance with the valve portion 61 that moves in any direction.

  And the valve body 6 changes the amount of protrusion from the outer shell casing 50 a according to the deflection of the diaphragm 51, the position of the valve portion 61 moves, and the area of the flow path between the valve portion 61 and the valve opening 42. The opening degree is adjusted by changing. In the present embodiment, as shown in FIG. 2, the air chamber closer to the pressure suppression air pipe 40 of the main body 50 of the pressure equalizing valve 5 is the primary chamber 52 and the other is the secondary chamber 53, and the diaphragm 51 is the primary. The degree of opening of the pressure control air flow path 4 increases as it bends toward the chamber 52 side, but it can also be set so that the degree of opening increases as it bends toward the secondary chamber 53 side. The arrangement of 52 and the secondary chamber 53 can also be set in reverse, and these are matters that can be arbitrarily designed.

  A furnace pressure control method using the furnace pressure control apparatus configured as described above will be described.

  First, when the furnace pressure is the same as the target pressure, the pressures in the primary chamber 52 and the secondary chamber 53 are balanced, and the diaphragm 51 is in a natural state without bending. At this time, the opening degree becomes a predetermined value and a predetermined amount of pressure-controlling air flows, and this state becomes an equilibrium state and the furnace pressure is maintained constant (target pressure).

  When the furnace pressure is lowered from the equilibrium state, the pressure in the primary chamber 52 becomes lower than the pressure in the secondary chamber 53, the diaphragm 51 is bent toward the primary chamber 52, and the valve body 6 moves in a direction protruding from the outer casing 50a. Thus, the opening degree increases and the flow rate of the suppression air flowing into the exhaust flue 3 increases. By increasing the flow rate of the control air that is lower than the temperature of the exhaust gas rising in the exhaust flue 3, the temperature of the new exhaust gas composed of the exhaust gas rising in the exhaust flue 3 and the control air is reduced. The furnace pressure is reduced by two effects: a reduction in draft due to a drop in the temperature of the original exhaust gas and an increase in flow resistance due to an increase in the flow rate of exhaust gas (new exhaust gas) rising in the exhaust flue 3. Swing towards higher. When the furnace pressure increases, the diaphragm 51 bends toward the secondary chamber 53 and the flow rate of the control air flowing into the exhaust flue 3 decreases, and the opposite effect to the above two effects, that is, the flow rate of the control air. The draft increases due to the rise in the temperature of the new exhaust gas rising in the exhaust flue 3 and the flow resistance decreases due to the decrease in the flow rate of the exhaust gas rising in the exhaust flue 3. Due to the effect, the furnace pressure swings toward the lower side, so that the equilibrium is achieved in balance with the target pressure. Also, when the furnace pressure increases from the equilibrium state, the explanation in which the level of pressure and the increase / decrease in the flow rate in the above description are reversed holds, and the equilibrium state is achieved by balancing with the target pressure.

  In the furnace pressure control method using the furnace pressure control device of the present invention, the pressure equalizing valve 5 described above is used, and unlike the conventional example, a furnace pressure gauge, a control valve, a controller, and a damper are not required, and the number of parts is reduced. In addition, there are no parts that are directly exposed to the high temperature in the furnace 1, and there are only a few movable parts such as the diaphragm 51 (and the valve body 6). This is unnecessary and does not require power and can be performed at low cost.

  Further, when the induction fan 31 is not provided in the exhaust flue 3 as in the example shown in FIG. 1, the blower 43 is provided at the upstream end of the suppression air passage 4 as in the example shown in FIG. 3. By connecting or connecting a branch flow path 44 from the blower 20 that sends air to the combustion device 2 to the upstream end of the pressure suppression air flow path 4 as in the example shown in FIG. Inflow to the exhaust flue 3 can be ensured.

  Further, as an example in which the example shown in FIG. 3 is further improved, as shown in FIG. 5, a nozzle 45 disposed in the exhaust flue 3 may be provided at the downstream end of the air flow passage 4 for suppression. . In the example shown in FIGS. 1 to 4, the downstream end of the suppression air passage 4 is simply connected to the side wall of the duct 30 of the exhaust flue 3, but in the example shown in FIG. 5, the suppression air passage 4 The downstream end of the exhaust flue 3 is further extended and disposed at a substantially central portion of the exhaust flue 3, and a nozzle 45 is provided at the tip of the exhaust flue 3 toward the upstream side of the exhaust flue 3. In this example, a dedicated blower 20 is connected to the upstream end of the air flow path 4 for suppression as in the example shown in FIG. 3, but air is sent to the combustion device 2 as in the example shown in FIG. It may be shared with the blower 20.

  In this example, when the furnace pressure is lowered from the equilibrium state, the diaphragm 51 is bent toward the primary chamber 52 side, the opening degree is increased, and the flow rate of the suppression air flowing into the exhaust flue 3 is increased. Since the pressure control air is ejected toward the upstream side of the exhaust flue 3, the flow rate of the new exhaust gas composed of the exhaust gas rising in the exhaust flue 3 and the pressure control air is reduced, and the furnace pressure is increased. Swing to become. When the furnace pressure decreases, the furnace pressure swings toward the higher one and balances with the target pressure to achieve an equilibrium state.

  Further, as shown in FIG. 6, the direction of the nozzle 45 is provided so as to eject the air for controlling the pressure toward the downstream side of the exhaust flue 3, and the inner wall of the duct 30 of the exhaust flue 3 is provided at the tip of the nozzle 45. May be bulged inward to form the throat portion 32 and the exhaust flue 3 may be throttled.

  In this example, when the flow rate of the suppression air increases, the flow rate of the exhaust gas rising in the exhaust flue 3 increases due to the ejector effect and swings toward the lower furnace pressure. It is necessary to set so that the flow rate increases. That is, the air chamber closer to the pressure control air pipe 40 of the main body 50 of the pressure equalizing valve 5 is used as the secondary chamber 53 and the other is used as the primary chamber 52, or the primary chamber 52 and the secondary chamber 53 are left as they are. Thus, it is necessary to make the opening degree smaller as the valve body 6 moves in a direction protruding from the outer casing 50a.

  The examples shown in FIGS. 5 and 6 can provide the same effects as the examples shown in FIGS.

  Next, another embodiment will be described with reference to FIG. The description similar to that of the above embodiment shown in FIGS. 1 to 6 is omitted, and different portions will be described.

  The present embodiment is different in that the regenerative alternating combustion device 2 is used as the combustion device 2 and the exhaust flue 3 is not used.

  The regenerative alternating combustion apparatus 2 alternately burns a pair of burners 21, and as shown in FIG. 7, a pair of burners 21 are provided on the furnace wall 11, and a heat storage body 22 is accommodated in each of the pair of burners 21. The heat storage chamber 23 is attached. Then, the supply blower 24 and the exhaust blower 25 are respectively connected to both burners 21 via the four-way valve 26, and both the burners 21 are alternately burned, and the other burner 21 is burned while one burner 21 is burning. The exhaust gas at high temperature in the furnace 1 is discharged through this time, and at this time, the heat storage body 22 recovers heat, and then the combustion air is preheated with the heat recovered by the heat storage body 22 when the other burner 21 burns. Is. Reference numeral 27 in the drawing is an air supply pipe that connects the air supply blower 24 and the four-way valve 26, and reference numeral 28 is an exhaust pipe that connects the exhaust blower 25 and the four-way valve 26. Instead of using the four-way valve 26, the air supply blower 24 and the exhaust blower 25 may be separately connected to both the burners 21 and controlled by opening and closing the valves of the respective connecting pipes.

  For this reason, it is not necessary to provide the exhaust flue 3 in the furnace 1, and the flow path through the burner 21 on the exhaust gas exhaust side functions as the exhaust flue 3.

  The pressure-control air flow path 4 has a downstream end connected to the exhaust pipe 28. As in the example shown in FIG. 1, the pressure equalizing valve 5 connects the pressure guiding tube 13 between the introduction hole 52 a of the primary chamber 52 and the lead-out hole of the furnace wall 11, and the introduction hole 53 a of the secondary chamber 53 serves as a target pressure. Open to the atmosphere.

  When the furnace pressure is the same as the target pressure, the pressures in the primary chamber 52 and the secondary chamber 53 are balanced, the diaphragm 51 is in a natural state, the opening of the pressure equalizing valve 5 is a predetermined value, and a predetermined amount. The furnace pressure is maintained at the target pressure in an equilibrium state where the air for controlling pressure flows.

  When the furnace pressure is lowered from the equilibrium state, the pressure in the primary chamber 52 becomes lower than the pressure in the secondary chamber 53, the opening degree is increased, and the flow rate of the control air flowing into the exhaust pipe 28 is increased. The temperature of the exhaust gas flowing in the exhaust pipe 28 is lowered to reduce the draft, and the furnace pressure is increased by two effects of increasing the flow resistance due to the increase in the flow rate of the exhaust gas flowing in the exhaust pipe 28. Swing. When the furnace pressure is increased, the opening degree is decreased, the flow rate of the control air flowing into the exhaust pipe 28 is reduced, and the furnace pressure is oscillated. Thereby, it balances with target pressure and will be in an equilibrium state.

  In the example shown in FIG. 7, the upstream end of the suppression air flow path 4 is opened to the atmosphere, and air in the atmosphere is sucked by natural intake, but as in the example shown in FIG. By connecting the upstream end of the pressure control air passage 4 to the middle of the air supply pipe 27 and supplying air from the air supply blower 24, the flow rate of the pressure control air can be secured.

  Also in this embodiment, a furnace pressure gauge, a control valve, a controller, and a damper are unnecessary, the number of parts can be reduced, there are no parts that are directly exposed to the high temperature in the furnace 1, and there are no movable parts. Only the diaphragm 51 (and the valve body 6) is small, and it is excellent in reliability and durability, is not particularly required to be adjusted, does not require electric power, and can be performed at low cost.

It is sectional drawing of the furnace which provided the furnace pressure control apparatus of one Embodiment of this invention. It is sectional drawing of the pressure equalization valve and the air flow path for pressure control in a furnace pressure control apparatus same as the above. It is sectional drawing of the other example of the furnace which provided the furnace pressure control apparatus of embodiment same as the above. It is sectional drawing of the further another example of the furnace which provided the furnace pressure control apparatus of embodiment same as the above. It is sectional drawing of the further another example of the furnace which provided the furnace pressure control apparatus of embodiment same as the above. It is sectional drawing of the further another example of the furnace which provided the furnace pressure control apparatus of embodiment same as the above. It is sectional drawing of the furnace which provided the furnace pressure control apparatus of other embodiment. It is sectional drawing of the other example of the furnace which provided the furnace pressure control apparatus of embodiment same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace 10 Furnace space 11 Furnace wall 12 Exhaust port 13 Pressure guiding pipe 2 Combustion device 20 Blower 21 Burner 22 Heat storage body 23 Heat storage chamber 24 Supply air blower 25 Exhaust air blower 26 Four-way valve 27 Supply air pipe 3 Exhaust flue 30 Duct 31 Induction fan Reference Signs List 32 Throat part 4 Air flow path for pressure suppression 40 Air pipe for pressure suppression 41 Through hole 42 Valve opening 43 Blower 44 Branching flow path 45 Nozzle 5 Pressure equalizing valve 50 Main body part 50a Outer shell casing 50b Insertion hole 51 Diaphragm 52 Primary chamber 52a Introduction hole 53 Secondary chamber 53a Introduction hole 6 Valve body 61 Valve part

Claims (2)

  A furnace pressure control device provided with a combustion device as a heating means in a furnace, connected to an exhaust flue, connected to the exhaust flue with a pressure control air flow path, and provided with a pressure equalizing valve in the pressure control air flow path. The pressure equalizing valve has a primary chamber and a secondary chamber that are partitioned by a diaphragm to which a valve body is connected, and the primary chamber and the secondary chamber each have an introduction hole that communicates the inside and the outside. A pressure guiding tube is connected between the inlet hole formed in the furnace and the outlet hole formed in the furnace and communicating with the inside and outside of the furnace, and the inlet hole of the secondary chamber communicates with the space having the target pressure gas to A furnace pressure control device characterized in that the higher the pressure in the primary chamber is, the smaller the opening of the air flow passage for pressure control is. A furnace pressure control method for a furnace provided with a combustion device as a heating means and connected to an exhaust flue, wherein a pressure control air flow path is connected to the exhaust flue, and the pressure control air flow path is internally to a pressure equalizing valve having a primary chamber and a secondary chamber which is partitioned by a diaphragm provided with the pressure in the primary chamber by introducing the gas in the furnace in the primary chamber same as furnace pressure, the secondary chamber Introduce a target pressure gas to set the secondary chamber air pressure as the target pressure, and adjust the opening of the suppression air flow path to be smaller as the primary chamber pressure is higher than the secondary chamber pressure. A furnace pressure control method characterized by controlling the flow rate of the control air and setting the furnace pressure as a target pressure.

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