JPH0128294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device for a forced-feed, exhaust-type gas combustor.

Conventionally, a pressure detection port of a pressure impulse pipe of a pressure switch is inserted into one of the suction passage or the discharge passage, and the wind pressure generated by a blower fan is guided from the pressure detection port to the diaphragm chamber through the pressure impulse pipe, and for example, the pressure switch is inserted into one of the suction passage or the discharge passage. The change in the wind pressure difference is converted into the displacement of the diaphragm, and the limit switch is turned on and off based on this displacement. If the specified wind pressure cannot be obtained, that is, the amount of air supplied to the combustion chamber is insufficient to completely burn the supplied gas. Various safety devices have been proposed that prevent incomplete combustion by turning off the limit switch and stopping the gas supply when the gas is insufficient, but the operating point (wind pressure setting point) of these safety devices is limited to one point. Therefore, when the air flow rate changes as the combustion capacity changes, the wind pressure at the pressure detection port changes, and in gas combustors where the combustion capacity changes, a wind pressure switch should be used to prevent incomplete combustion. It is extremely difficult to use this type of safety device for forced-feed, exhaust-type gas combustors whose combustion capacity is switched stepwise or continuously.

This invention solves this drawback.When the amount of gas supplied for combustion is changed by switching the combustion capacity, and the blowing capacity of the blower fan is simultaneously changed accordingly, the amount of air blown is changed. Wind pressure changes as the air volume changes, but by installing a wind pressure regulator on the suction side of the fan that automatically changes the air volume and increases intake resistance as the air volume decreases, it is possible to Increase the cross-sectional area of the suction passage,
When the combustion capacity is small, the cross-sectional area of the suction passage is made small so that a close wind pressure can be obtained at the pressure detection port regardless of the size of the air blowing capacity, that is, the amount of air blowing. It is possible to detect whether or not the appropriate amount of air is being sent to the combustion chamber of the gas combustor, and the limit switch is activated at a similar wind pressure value.

Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 show an embodiment in which the present invention is applied to a forced air type gas combustor. 1 is a Sirotskov fan installed in a fan case 13, which is rotated by a fan motor 2. A pressure detection port 5 at one end of a pressure impulse pipe 4 is installed inside the Sirotskov fan 1 to open toward the discharge port 3a of the supply air discharge pipe 3, and the other end of the pressure impulse pipe 4 is connected to a diaphragm constituting a wind pressure switch A. Diaphragm chamber 6 of main body 15
is connected to. C is a gas combustor, and a discharge pipe 3 is connected to its air supply port. B is a wind pressure regulator that presses a valve body 8 in the control chamber 7 with a spring 9 in the direction of the valve seat 10 provided at the inlet 3b of the control chamber 7, that is, in the direction of narrowing the ventilation cross-sectional area of the inlet 11. The wind pressure regulator B is connected to the Sirotskov fan case 13 via the suction pipe 12. Note that 14 is a peripheral wall of the control chamber 7.

Fig. 5 is an air volume vs. wind pressure curve obtained by plotting the respective values of the air volume Q and negative wind pressure P obtained by the Sirotskov fan 1 on the horizontal and vertical axes.
E is the air volume vs. wind pressure curve obtained when the rotation speed, etc. of the Sirotskov fan 1 is increased, and when the rotation speed, etc. of the Sirotskov fan 1 is decreased, respectively.Curves F and G are obtained when the intake resistance is small and large, respectively. The inspiratory resistance curve is shown. Therefore, when the combustion capacity is switched to small and the amount of gas provided for combustion is reduced, the fan motor 2 is operated to send an amount of air supply suitable for the amount of supplied gas to the combustion chamber of the gas combustor C. The rotational speed and the like of the Sirotskov fan 1 are reduced, thereby reducing the amount of air supplied by the Sirotskov fan 1 into the combustion chamber. As the amount of air supply decreases, the differential pressure generated before and after the valve body 8, which is caused by the throttling action of the gap between the peripheral wall 14 and the valve body 8 of the wind pressure regulator B, becomes smaller, and the biasing force of the spring 9 causes the valve body 8 to close. It moves closer to the seat 10, and the distance therebetween becomes small to a. As a result, the intake resistance increases, so the air supply air volume obtained at the intersection K of curve E and curve G in FIG. 5 becomes _Q2 , and the obtained negative pressure at the pressure detection port 5 becomes _P2 , The negative pressure P ₂ is raised from the negative pressure P ₂ ' at the intersection N between the curves E and F by the movement of the valve body 8 of the air pressure regulator B, that is, by the decrease in the amount of supplied air.

Next, when the combustion capacity is switched from small to large and the amount of gas provided for combustion is increased, the rotation speed etc. of the Sirotskov fan 1 are increased in the same way as above,
As a result, the gas combustor C is
The amount of air supplied to the combustion chamber increases. As the amount of air supply increases, the differential pressure generated across the valve body 8 due to the throttling action of the intake port 11 increases, and the valve body 8 moves away from the valve seat 10 against the biasing force of the spring 9. The gap increases to b, which reduces the intake resistance, so in Fig. 5, the curve D
The supply air volume obtained when the state of intersection L with the curve F is reached is Q ₁ , and the obtained negative pressure at the pressure detection port 5 is P ₁ ,
Negative pressure P ₁ is caused by the movement of the valve body 8, that is, due to the increase in the supply air volume, the negative pressure at the intersection M between the curve D and the curve G
It is lower than P ₁ ′.

As mentioned above, when the capacity of the Shirotsuko fan 1 is set as large and small, the negative pressure of the pressure detection port 5 becomes P ₁ and P ₂ respectively,
Since P ₁ and P ₂ can be set to similar values, they can be kept within the same on (off) range of the limit switch 16 of the wind pressure switch A.

Next, during combustion, exhaust gas is suppressed, and if a blockage in the exhaust stack or a failure of Sirotskov fan 1 (fan motor 2) occurs, and the required amount of air supply that matches the amount of gas to be supplied cannot be sent to the combustion chamber, check The negative pressure in the pressure port 5 moves in a direction smaller than the curve E, and the moving distance of the valve body 8 to the valve seat 10 also disappears, becoming smaller than the negative pressure _P2 , the limit switch 16 is turned off, and the combustion gas flows into the combustion chamber. supply will be stopped. In this way, safety can be ensured by using the existing limit switch to control gas supply and disconnection to ensure the required amount of air supply.

What is shown in FIG. 3 is a different embodiment of the present invention.In place of the valve body 8 of the wind pressure regulator B in the above embodiment, an air intake hole is provided in the center of an elastic sheet 17 made of rubber or the like, as shown in FIG. 18 and the intake hole 18
A radial cut 19 is formed around the inlet 3b, and the elastic sheet 17 made of rubber or the like is inserted into the inlet 3b shown in FIG.
The intake hole 18 and the intake port 3b are installed in a substantially concentric manner, thereby automatically throttling and adjusting the amount of air supplied. In this case, as in the above embodiment, when the combustion capacity is large, the differential pressure generated before and after the elastic sheet 17 caused by the throttling action of the intake hole 18 of the Sirotskov fan 1 is large, and the air intake hole 18 of the elastic sheet 17 has a notch 1.
The 9th part is greatly pressed and curved in the direction of the Sirotskov fan 1, and the notch 19 is widened to form the intake hole 1.
The diameter of 8 is larger than that of d, and the area of the intake port 3b is larger than that of c. When the combustion capacity is low, the degree of curvature is small, and similarly, the diameter d of the intake hole 18 is smaller than c, and the area of the intake port 3b is smaller. This allows the negative pressures P ₁ and P ₂ of the respective pressure detection ports 5 to be maintained at close values in the same manner as described above even if the amount of air supply is changed in accordance with the magnitude of the combustion capacity.

In the embodiment described above, the pressure detection port 5 was inserted and installed directly inside the blade of the Shirotsuko fan 1 toward the discharge port 3a to apply the flow pressure of the airflow and obtain a large negative pressure. Fan and wind pressure regulator B
It may be inserted and arranged on the suction side between the valve body 8 of
Alternatively, it may be provided on the discharge side of the blower fan, in which case the sensed wind pressure will be positive. Furthermore, the safety device according to the present invention can be applied to a forced exhaust type, in which case the suction port 3b is connected to the exhaust duct of the gas combustor C, or the suction port 3b is divided by the suction pipe 12 and the suction port is connected to the blower fan side. If the pipe 12 is connected to the exhaust duct of the gas combustor C, and the suction pipe 12 on the wind pressure regulator B side is connected to the air supply port of the gas combustor C, the air volume flowing through the suction pipe 12 and the discharge pipe 3 will be the same. Therefore, the same effect as described above can be obtained.

As described above, this invention has a simple configuration in which a wind pressure adjustment device with an automatic throttling function is installed on the intake side of the blower fan, and the blowing capacity of the blower fan can be changed by switching the combustion capacity between high, medium, and low. Automatic throttle function changes the cross-sectional area of the suction passage to reduce intake resistance.
(Medium), it is possible to maintain the wind pressure at the pressure detection port at a close value by changing it greatly, so it is possible to check whether the appropriate amount of air supply is being sent to the combustion chamber at any combustion capacity stage. Since the wind pressure at the pressure detection port can be detected using a single existing limit switch, the exhaust can be suppressed regardless of the combustion capacity stage, and if a blockage of the exhaust stack occurs, the limit switch of the wind pressure switch is always turned on. It is a practical invention that can ensure safety by controlling gas supply and disconnection by turning it off.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of the present invention installed on the air supply side of a forced-feed, exhaust type gas combustor, Fig. 2 is an enlarged view of its main parts, and Fig. 3 is an enlarged view of its main parts similarly showing another embodiment. 4 are front views of the main parts thereof, and FIG. 5 is a diagram showing the relationship between air volume and wind pressure. 1...Blower fan (Shirotsukofan), 3...Discharge pipe, 4...Pressure pipe, 5...Pressure detection port, 7...Control room, 8...
Valve body, 9... Spring, 10... Valve seat, 15... Diaphragm body, 17... Elastic sheet, 18... Intake hole, 1
9...notch, A...wind pressure switch, B...wind pressure regulator.

Claims (1)

[Scope of Claims] 1. In a device that forcibly supplies and exhausts gas to a gas combustor using a blower fan, the blower fan may be inserted into the blower fan suction path or discharge path with a pressure detection port opened at one end, and other The end is connected to the diaphragm chamber that constitutes the wind pressure switch, and the cross-sectional area of the suction path of the blower fan automatically changes in size depending on the increase or decrease in air volume, increasing the intake resistance as the air volume decreases. A safety device for a forced-feed, exhaust-type gas combustor, characterized by the installation of a wind pressure regulator. 2 As a structure that automatically changes the cross-sectional area of the suction passage, the valve body is installed so as to be biased by a spring toward the valve seat provided at the suction port of the control chamber, and the valve seat is pushed by the suction force of the blower fan. A safety device for a forced-feed, exhaust-type gas combustor according to claim 1, which is installed so as to be further away from each other. 3. As a structure that automatically changes the cross-sectional area of the suction passage, an elastic sheet with an intake hole in the center and radial cuts around the intake hole is fixed to the suction passage, and the suction force of the blower fan is changed. Claim 1, wherein the intake hole is installed so that the diameter thereof increases.
Safety devices for forced-feed, exhaust-type gas combustors as described in Section 2.