JPH0765726B2 - Boiler safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to, for example, a boiler safety device that performs intermittent control of a heating control system for can water, particularly when the vapor pressure of the can water exceeds a predetermined value. It relates to an improvement of the safety device that operates.

<Prior Art> Conventionally, as a typical boiler system to which the structure of the present invention can be attached, for example, one described in JP-B-63-37841 is known.

FIG. 1A is a block diagram showing the structure of such a boiler system, and the cross section of the boiler 1 is shown.

FIG. 1B is a sectional view taken along line AA in FIG. 1A.

In the figure, a large number of water pipes 1b are erected inside the boiler 1 along the inner peripheral surface of the wall 1a. The water pipes 1b are hollow cylinders, the lower end of which is an annular lower pipe head 1c (water chamber). ), And its upper end is also an annular upper header 1d (steam chamber)
Cans are stored under the lower pipe head 1c and the water pipe 1b, respectively.

A combustion chamber 1e is formed in the center of the boiler 1 surrounded by the water pipe 1b. An air passage 1h communicating with a blower 1g driven by an electric motor 1f is provided above the boiler 1, and inside the air passage 1h,
The heating device F is formed by vertically arranging the nozzle rod 1i and the electrode rod 1j.

The lower end of the combustion chamber 1e passes through the hollow parts of many water pipes 1b, and the flue
Connect to 1k. From the upper header 1d, a communication pipe 1l extends outside the wall 1a and communicates with the lower header 1c.

A water level gauge 1m that visually displays the water level of the can water and a water level detection unit 2 are provided in the middle of the communication pipe 1l. A water supply control unit 3 is connected to the water level detection unit 2, and its output terminal is connected to an electric motor 4 a that drives a water supply pump 4. An inlet pipe of the water supply pump 4 communicates with a water source (not shown), and its discharge pipe communicates with the lower header 1c.

Furthermore, the pressure detecting unit 5 is connected to the upper part of the communication pipe 1l,
The output terminal is connected to the combustion control unit 6. Control signal lines 6a ′ to 6c ′ extend from the combustion control unit 6 and are connected to the electric motor 1f, the electrode rod 1j, and the fuel pump 6d ′, respectively. The introduction pipe of the fuel pump 6d 'communicates with a fuel tank (not shown),
The discharge pipe is connected to the nozzle rod 1i. Then, the blow pipe 1n extends from the lower header 1c and communicates with a drainage channel (not shown) via the blow cock 1p, and the steam pipe 1q extends from the upper header 1d and communicates with a desired steam load (not shown). .

In the configuration of the steam boiler system, when generating steam, a high voltage is applied to the electrode rod 1j while pumping air into the wind passage 1h through a blower unit consisting of a blower 1g driven by an electric motor 1f and nozzles. The fuel injected from the tip of the rod 1i is ignited and burned in the combustion chamber 1e. The high-temperature combustion gas generated by such combustion flows from the lower end of the combustion chamber 1e to the water pipe 1b.
It enters the hollow part of the building, passes through it, reaches the flue 1k, and is exhausted. During this time, heat exchange is performed and the canned water in the water pipe 1b is heated to become steam, which is collected and accumulated in the upper header 1d and supplied to the steam load through the steam pipe 1q.

Then, regarding combustion control, the vapor pressure in the upper header 1d is extracted through the communication pipe 11 and supplied to the pressure detection unit 5,
When the pressure detection unit 5 detects that the vapor pressure in the upper header 1d has reached the preset lower limit vapor pressure, when it detects that the lower limit vapor pressure signal has similarly reached the upper limit vapor pressure, , And sends an upper limit vapor pressure signal to the combustion control unit 6.

When the steam control unit 6 receives the lower limit steam signal from the pressure detection unit 5 when the steam consumption continues and the steam pressure in the upper header 1d drops, the combustion control unit 6 starts the electric motor 1f through the control signal 6a ′. A high voltage is applied to the electrode rod 1j through the control signal line 6b 'after the air passage 1h is air-purged by the blower 1g, and the fuel pump 6d' is started through the control signal line 6c ', which is injected from the nozzle rod 1i. The fuel is ignited to start combustion, and further steam generation continues and the vapor pressure rises,
When the upper limit atmospheric pressure signal is received from the pressure detection unit 5, the fuel pump 6d 'is stopped through the control signal line 6c' to cut off the fuel supply, thereby stopping the combustion and waiting for the discharge of the combustion gas. Electric motor through signal line 6a '
Stop 1f and cut off the blow from 1g blower.

Thus, due to such intermittent control of combustion, the upper head 1d
The inside vapor pressure can be maintained as a pressure value between both pressure values set in advance as upper and lower limit vapor pressures.

In a simple device, the start / stop control of the electric motor 1f and the fuel pump 6d ′ and the application of the high voltage to the electrode rod 1j may be performed simultaneously.

Furthermore, regarding the water supply control, the air-water interface in the communication pipe 1l,
That is, when the change in the can water level in the water pipe 1b is transmitted to the water level detection unit 2, and the water level detection unit 2 detects that the can water level reaches a preset lower limit water level, the lower limit water level signal When it is detected that the upper limit water level has been reached, an upper limit water level signal is sent to the water supply control unit 3.

When the water level of the can water in the water pipe falls due to the consumption of steam and the lower limit water level signal is received from the water level detection unit 2, the water supply control unit 3 starts the electric motor 4a and the water supply pump 4 causes the water pipe 1b to pass through the lower pipe head 1c to the water pipe 1b. When the water level in the can rises and the upper water level signal is received from the water level detection unit 2, the electric motor 4a is stopped and the water supply to the water pipe 1b is cut off.

Thus, the intermittent control of the water supply makes it possible to maintain the water level of the can water in the water pipe 1b at a water level value between the two water level values set in advance as the upper and lower water levels.

Then, the intermittent control of the supply water and the intermittent control of the combustion are separately and independently performed.

Further, when the can water is blown, the blow cock 1p is opened to allow the lower pipe head 1c and the water pipe 1b to pass through the drain pipe 1n.
It can blow some or all of the canned water inside.

Before the steam pressure of the boiler 1 rises excessively to the steam pipe 1q and the boiler 1 becomes in a dangerous state, the steam in the upper header 1d is discharged to suppress the pressure increase there. A safety valve 1z is provided that opens at a very high pressure, which is considerably higher than the upper limit pressure related to intermittent control of combustion.

However, the safety valve 1z is provided only in case of emergency, and its opening may not only lead to an inoperable state of the boiler system, but also a large amount of high-temperature steam is discharged outside the boiler. As a result, there is a great economic burden in terms of the disadvantages of the function stoppage and the heat loss due to discharge.

Therefore, in such a boiler system, there is an example in which a safety device as shown in FIG. 2 is provided. That is, the electromagnetic changeover switch 7 is provided between the power supply terminal of the combustion control unit 6 and the power supply line BL, and the abnormal high pressure detection unit 8 provided in the communication pipe 1l is connected to the drive terminal of the electromagnetic changeover switch 7. When the abnormal high pressure detection unit 8 detects a vapor pressure in the communication pipe 1l that exceeds a preset abnormal high pressure that is equal to or higher than the above-described upper limit vapor pressure related to combustion control, the electromagnetic changeover switch 7 The movable contact 7a is switched from the connection state with the normally closed contact 7b to the connection state with the normally open contact 7c, and the combustion control unit 6 is disconnected from the power supply line BL, so that the power supply is cut off there. As a result, the operation of the boiler 1 is stopped.

<Problems to be Solved by the Invention> However, in the configuration of the above-described conventional technique, particularly in a boiler with a small amount of steam used and a small heat capacity, the above-described abnormal high pressure detection unit 8 and the electromagnetic changeover switch 7 cooperate. Even if the combustion is stopped by working, the heat capacity in the combustion chamber 1e is relatively large, so the vapor pressure continues to rise further to the extremely high pressure above the abnormally high pressure as a result of the heat storage here. There is a possibility that the safety valve 1z in the steam pipe 1q may be opened in addition to the operation of the abnormal high pressure detection unit 8. In this case, not only the boiler becomes inoperable until the safety valve 1z is restored, We encounter the problem that a large amount of heat is lost from the safety valve.

To alleviate this problem, the normally open contact 7c of the electromagnetic changeover switch 7 is connected to the solenoid valve 17 via the relief valve control line 16 as shown by the imaginary line (dashed line) in FIG. Control terminal
There has been proposed a safety device in which a relief valve that can be opened at an abnormally high pressure equal to or lower than an extremely high pressure is configured by connecting the solenoid valve 17 to a relief valve body 18 by connecting the solenoid valve 17a. In the proposed safety device, the movable contact 7a of the electromagnetic switch 7 is a normally open contact.
When it is connected to 7c, the solenoid valve 17 is driven and the relief valve body 18
To force the valve to open. As a result, the steam of the boiler 1 is discharged through the escape valve body 18 in conjunction with the combustion stop at an abnormally high pressure, so that the steam pressure decreases more sharply, and as a result,
The safety valve 1z is prevented from opening.

However, in the case of such a safety device proposed by the improvement, the relief valve body 18 is forcibly opened, so that more steam is discharged than necessary, and at that time, the normal relief valve does not pass through steam. As a result, there is a problem in that the silencer is required, which eventually complicates the facility and lowers the thermal efficiency of the boiler system.

<Means for Solving Problems> The invention according to claim 1 has a problem that a frequent opening of a safety valve in the above-mentioned prior art causes a harmful effect and a large amount of heat loss due to steam discharge from a relief valve in the proposed technology causes a problem. In view of the point, the abnormal high pressure detection means for detecting that the vapor from the water pipe is higher than the upper limit vapor pressure and increased to the abnormal high pressure lower than the extremely high pressure, and the abnormal high pressure detected by the detection means By overriding the start and stop of the heating device by the control means, and by additionally providing the forced air blowing drive means for forcibly driving the air blowing means, the above problems are solved and an abnormal rise in the steam pressure of the boiler is made effective. It is an object of the present invention to provide an excellent safety device for a boiler system, which can suppress the operation frequency of the safety valve and the relief valve extremely low, although it can be suppressed.

Like the invention of claim 1, the invention of claim 2 is made in view of the problems of the opening frequency of the safety valve, noise reduction during steam discharge, and heat loss. In addition to solving the above problems, power saving and equipment wear prevention are also provided by additionally providing timer means for cooperating with the air blowing driving means to limit the forced driving operation of the air blowing means to a predetermined period. It is intended to provide an excellent boiler safety device that also achieves the above.

<Operation> The configuration of the invention of claim 1 is easy to understand with reference to FIG. 3, but the upper limit vapor pressure that governs the operation stop of the heating device F by the combustion control means 6 and is considerably higher than that. If the abnormal high pressure is set between the operating pressure of the safety valve 1Z set to the extremely high pressure and the abnormal high pressure detecting means 8 detects the rise of the vapor pressure to the abnormal high pressure, it is included in the heating device F. In addition to the heating device itself, the forced air blowing driving device 7 prioritizes the start and stop of the heating device F by the combustion control means 6 with the air blowing means 1f and 1g capable of sending air to the water pipe facing the heating device. By forcibly driving, the heating device F itself and the water pipe 1b act to be air-cooled.

The configuration of the invention of claim 2 is easier to understand, for example, as shown in FIG. 6, but in FIG. 3 showing the configuration of the invention of claim 1, the forced air blowing drive means 7 is the abnormal high pressure detection means 8. When driven by the operation, the timer means 19 is operated at the same time as the operation, and the blowing means 1f and 1g are forcibly driven only during the operation time of the timer means 19.

<Embodiment> FIG. 3 is a block diagram showing the construction of the first embodiment of the present invention, which is the same as the constituent elements shown in FIGS. 1A, 1B and 2 used for explaining the prior art. The same reference numerals are given to the constituent elements.

The normally open contact 7c of the electromagnetic changeover switch 7 as the forced air blowing drive means is provided with a blower as the air blowing means via the air blowing control line 12.
It is also connected to 1g and the electric motor 1f that drives it.

In operation, the first embodiment configured as described above
The vapor pressure in the upper pipe head 1d and then in the communication pipe 1l increases,
When this exceeds an abnormally high pressure equal to or higher than the upper limit vapor pressure related to combustion control, the abnormally high pressure detecting section 8 detects it and drives the electromagnetic changeover switch 7, and its movable contact 7a is made into the normally open contact 7c.
The operation of switching to the side is the same as that of the configuration proposed in FIG. 2, but in this case, since the electric power is fed from the power supply line BL to the electric motor 1f via the air blowing control line 12, the changeover switch 7 is forced to drive the air blowing means. And the blower 1g is forcibly driven.

Thus, by opening the normally open contact 7b of the electromagnetic changeover switch 7, the power supply to the combustion control unit 6 is cut off, so that the blower 1g is forcibly operated even though the combustion in the heating device F is stopped. As the air is continuously blown into the combustion chamber 1e via the heating device F, the entire boiler, and thus the water pipe 1b, is air-cooled and its temperature drops rapidly, and as a result, the upper header 1d The vapor pressure inside also falls rapidly.

FIG. 4 is a block diagram showing the configuration of the second embodiment of the present invention, in which can water is obtained by automatically controlling the configuration of the first embodiment shown in FIG. 3 and the automatic blow valve body 1p ′. The configuration shown in FIG. 3 is the same as the configuration shown in FIG. 3, and the same reference numerals are given to the same components. In FIG. 4, the normally open contact 7c of the electromagnetic changeover switch 7 is connected to the control terminal 9a of the electromagnetic valve 9 for driving the automatic blow valve body 1p ', and the electromagnetic valve 9 is normally closed. Contact 10a
The open blow switch 10 is connected to the automatic blow control unit 11 via a normally open contact 7c, and the drive terminal of the open / close switch 10 can be connected to the power line BL.

When the abnormal high pressure detector 8 is activated, the electromagnetic changeover switch 7 is driven as in the case of the first embodiment, and the blower is sequentially turned on.
1g is continuously driven, and as a result, air is continuously blown into the combustion chamber 1e, but in this case, the movable contact 7a of the electromagnetic switch 7 must be connected to the normally open contact 7c. Then, the electromagnetic open / close switch 10 is driven and its normally open contact 10
a is opened, the automatic blow valve body 1 by the automatic blow control unit 11
Since the automatic control of p'is stopped and the solenoid valve 9 is also driven to forcibly open the automatic blow valve body 1p ',
Through this, can water is discharged from the lower canner 1c in a cooperative manner, whereby the tendency of the vapor pressure to drop is further promoted and strengthened.

FIG. 5 is a block diagram showing a configuration of a third embodiment of the present invention, in which a steam / water separator 13 is connected to a steam pipe 1q extending from an upper header 1d, and the bottom of the steam / water separator is subject to precipitation. The check valve 14 is connected to the lower head 1c via the pipe 15, and is installed in the downcomer pipe.
Is provided. In addition, the normally open contact 7c of the electromagnetic switching valve 7
From which the relief valve control line 16 extends to the control terminal of the solenoid valve 17 in the middle, and the valve solenoid valve 17 is connected to the relief valve body 18 provided in the steam separator 13 and can be controlled to open and close. Is. The other components are the same as the components designated by the same reference numerals in the first embodiment shown in FIG.

At the time of boiler operation, the steam separator 13 drops the water in the steam introduced from the upper header 1d via the steam pipe 1q and separates it into a downward flow through the downcomer pipe 15 and the check valve 14 in one direction. It is known that the reflux recovery to the pipe 1c can simultaneously prevent damage to a steam load device (not shown) and gradually reduce heat loss.

While the abnormal high voltage detector 8 is operating, the electromagnetic changeover switch 7 is driven, and the blower 1q is forcibly continuously driven in the same manner as in the first embodiment. Power is supplied to the solenoid valve 17 via the normally open contact 7c of the changeover switch 7 and the relief valve control line 16, so that the solenoid valve 17 is excited to drive the relief valve element 18 to open it. Thus, the relief valve 18 is opened when the vapor pressure rises to an abnormally high pressure in the abnormally high pressure detection unit 8 which is selected as a pressure lower than the emergency pressure which is the operating pressure of the safety valve 1z. Since the vapor inside can be released at once, a rapid drop in vapor pressure is achieved.

FIG. 6 is a block diagram showing the configuration of the fourth embodiment of the present invention, and the same components as those of FIG. 3 showing the first embodiment are designated by the same reference numerals. There is.

The normally open contact 7c of the electromagnetic changeover switch 7 as the forced air blowing drive means has a monostable contact holding circuit 19 as the timer means.
A control terminal of (typically, a relay driven by a monostable multivibrator) is connected, and an output terminal of the monostable contact holding circuit 19 is connected to an electric motor 1f for driving a blower 1g.

Therefore, when the electromagnetic changeover switch 7 is driven during the operation of the abnormal high voltage detector 8, the monostable contact holding circuit 19 cooperates with the electromagnetic changeover switch 7 for a predetermined period, typically, the metastable time of the monostable multivibrator. The electric motor 1f is forcibly driven for a predetermined period set as, during this period, the blower 1g blows air to the combustion chamber 1e via the heating device F, and stops after the predetermined period has elapsed. In other words, since the air blown to the combustion chamber 1e is limited to the predetermined period that is preferably set in advance, the electric motor
Not only is unnecessary power supply to 1f prevented, mechanical wear due to unnecessary operation is prevented, and also supercooling of the entire boiler is avoided.

As an additional note, in each embodiment, the abnormal high pressure detection unit 8
Automatically returns when the vapor pressure falls to a pressure within the control range between the upper and lower limit pressures, and operates so as to entrust the combustion control unit 6 with the control of the blowing means (the blower 1g and the electric motor 1f).

<Effect> As described above, according to the invention of claim 1, an abnormal high pressure detecting means for detecting that the vapor from the water pipe has risen to an abnormal high pressure higher than the upper limit vapor pressure and lower than the extremely high pressure. At the time of abnormally high pressure detected by the detection means, by prioritizing the start and stop of the heating device by the combustion control means and by additionally providing the forced air blowing drive means for forcibly driving the air blowing means, When the temperature rises above the upper limit vapor pressure and reaches an abnormally high pressure, the vapor pressure rises further to reach an extremely high pressure, and before the safety valve opens, the water pipe is forcibly forced through the heating device that is stopped. Since it is air-cooled, it is possible to suppress further increase in vapor pressure and keep the safety valve operating at an extremely low frequency.
The excellent effect that the frequent stoppage of the operation due to the opening of the safety valve is extremely reduced is exhibited.

Moreover, even when the automatic opening operation of the automatic blow valve body is performed depending on the abnormal high pressure, the water pipe is air-cooled at the abnormal high pressure and a rapid pressure drop is achieved. There is also an advantage that the heat loss due to the discharge of can water can be minimized by minimizing the discharge of can water.

Also, the above advantages are secured in the same manner even when the steam in the upper header is discharged through the relief valve that opens due to the abnormal high pressure dependence, so the amount of vapor discharged through the relief valve is minimized accordingly. By making it smaller, the heat loss can be minimized.
In addition, there is an advantage that the silencer of the relief valve can be omitted.

According to the invention of claim 2, in cooperation with the forced air blowing driving means in the invention of claim 1, timer means for limiting the operation of the forced driving operation of the air blowing means to a preset predetermined period is attached. With this configuration, in addition to the effect of the invention of claim 1, it is possible to prevent the forced blow operation from being continued more than necessary, so that power saving and prevention of mechanical wear can be achieved at the same time. The excellent effect of being able to contribute to a large improvement in thermal efficiency by preventing the supercooling of the entire boiler is exhibited.

[Brief description of drawings]

1A and 1B relate to a conventional boiler to which the present invention is applicable, and FIG. 1A is a cross-sectional view showing the configuration thereof.
FIG. 1B is a sectional view taken along line AA of FIG. 1A. FIG. 2 relates to the proposed technique and is a block diagram in which the configuration of FIG. 1A is added. 3 to 6 relate to an embodiment of the present invention, FIG. 3 is a block diagram showing a configuration of the first embodiment, FIG. 4 is a block diagram showing a configuration of the second embodiment, FIG. 5 is a book diagram showing the configuration of the third embodiment, and FIG. 6 is a block diagram showing the configuration of the fourth embodiment. 1b …… water pipe, 1f …… motor 1g …… blower, 1z …… safety valve F …… heating device, 5 …… pressure detection means 6 …… combustion control device 7 …… forced air blowing drive means 8 …… abnormal high pressure detection means 19 ... Timer means

Claims (2)

[Claims] 1. A blower means 1f, 1g included in a heating device F for heating the water pipe 1b and capable of blowing air facing the water pipe, a pressure detecting means 5 for detecting a vapor pressure from the water pipe 1b, and a pressure detecting means. When the upper limit vapor pressure 5 detects the upper limit vapor pressure, the heating device F of the boiler is stopped, and when the lower limit vapor pressure is detected by the detection unit 5, the combustion control unit 6 that starts the heating unit F and the water pipe 1b In a boiler system that has at least a safety valve 1z that opens when it detects that the vapor pressure of has risen to an extremely high pressure that is considerably higher than the upper limit vapor pressure, the vapor pressure from the water pipe 1b is higher than the upper limit vapor pressure, and , An abnormal high pressure detection means 8 for detecting an increase in the abnormal high pressure lower than the extremely high pressure, and when the abnormal high pressure detection means 8 detects the abnormal high pressure, the combustion control means 6 gives priority to start and stop of the heating device F. hand,
Forced air blowing driving means 7 for forcibly driving the air blowing means 1f, 1g
Boiler-type safety device characterized by being attached. 2. The boiler system according to claim 1, further comprising timer means 19 which cooperates with the forced air blowing drive means 7 to forcibly drive the air blowing means 1f, 1g for a predetermined time set in advance. Safety device.