JPS6347963B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides heating control in a boiler system that prohibits heating operation in order to prevent the boiler from running dry when the can water level drops below a specific value for some reason. The present invention relates to an interlock device, and particularly relates to an improvement that can reliably prevent dry firing even when a communication pipe is blocked.

Conventionally, by introducing a portion of canned water into a communication pipe, the canned water level is transmitted to a water level detection section, and a control water level sensor installed in the water level detection section is used to control the canned water level in advance. A heating control interlock device that prohibits the operation of the heating device for heating the can water when it is detected that the water level has dropped to the can water level is often used.

However, in such conventional interlock devices, when the communicating pipe is blocked due to freezing or the like, the water level in the pipe is fixedly maintained at a certain position regardless of the water level in the can. Then,
If, as is often the case, the water level in the communicating pipe, which is kept fixed due to blockage, is higher than the water level in the control tank, the heating operation will not be prohibited and upon start of operation, The boiler is heated,
Even though the canned water level continues to fall, the water level detection unit is unable to detect that the canned water level has reached the lower limit water level that requires water supply to begin, and water supply continues to continue without any water being supplied. Since the heating operation continues, there is a disadvantage that the boiler is often brought to a dry state and burnt out.

In view of the problems of communication pipe blockage in the interlock device based on the above-mentioned prior art, an object of the present invention is to prohibit the heating operation when starting water supply at the start of boiler operation, and further prevent water level changes after starting water supply. We provide an excellent interlock device for heating control in a boiler system that eliminates the above drawbacks by detecting and canceling the inhibition of heating operation, and can reliably prevent dry heating even when the communication pipe is blocked. This is what I am trying to do.

The configuration of the present invention in accordance with the above object is an intermittent heating control that stops the heating operation when the steam pressure rises to the upper limit steam pressure, and starts the heating operation when the steam pressure falls to the lower limit steam pressure. and an intermittent control water supply control section that stops the water supply operation when the canned water level rises to the upper limit water level and starts the water supply operation when the canned water level falls to the lower limit water level. When water supply is started at the start of operation of the boiler system, the interlock state is stored in the interlock state storage section, an interlock signal is sent to the heating control section to prohibit the heating operation, and furthermore, the water supply is started. Later, when the water level change detection unit detects that the canned water has reached the lower limit water level or the upper limit water level, the memory of the interlock state is cleared, the interlock signal is extinguished, and the heating operation is prohibited. The gist of this is to remove the .

Further, a second configuration of the invention related to the present invention is that in the configuration of the present invention described above, the water level change detection section is modified so that when the can water level reaches a control water level selected below the lower limit water level. In addition, it detects water level changes and cancels the prohibition of heating operation.
An interlock signal generation section is attached, so that the interlock signal can be generated not only when the interlock state is stored in the interlock state storage section, but also when it is detected that the canned water level has fallen below the control water level. The gist is that a lock signal is sent to the heating control section to inhibit heating operation.

An embodiment of the present invention will be described below based on FIGS. 1 to 3.

FIG. 1 is a block diagram showing the configuration of the above embodiment, in which a boiler A is surrounded by a side wall a, and a number of water pipes b are erected along the inner circumference of the boiler A, and the upper and lower parts of the water pipes b are annular. They are connected to form an upper header c and a lower header d, respectively.

Adjacent to the upper wall e of the boiler A are a blower g that is linked to a motor f, a fuel injection rod j that is connected to a fuel pipe i that communicates with a fuel tank (not shown) via a fuel valve h, and an electrode rod k. The combustion chamber m is surrounded by an air passage l communicating with the blower g.
A burner B having an opening is formed.

A communicating pipe n is extended between the upper and lower headers c and d, and a steam pressure detecting section 1 and a water level detecting section 3 are connected to the upper and lower parts of the communicating pipe n, respectively. A steam pipe o extends from the upper header c and is connected to a steam load (not shown).

A drain pipe P extends from the lower header d to a drainage channel (not shown), and in the drain pipe P there is a block q.
is provided.

Furthermore, a water supply pipe u extends from the lower header d to a water source (not shown), and a pump w driven by an electric motor v is provided in the pipe u.

Note that x is a water level gauge connected to the communication pipe n.

The steam pressure detection unit 1 includes a pressure sensor 1 to which steam pressure in the upper header c is guided through a communication pipe n.
a, first and second comparators 1b and 1c whose respective first input terminals are connected to the output terminal of the pressure sensor 1a, and the first and second comparators 1
reference voltage sources 1d and 1e connected to the second input terminals of the reference voltage sources 1d and 1c, respectively.

The heating control section 2 includes a flip-flop 2b, in which the output terminal of the first comparator 1b is connected to its set terminal, and the output terminal of the second comparator 1c is connected to its reset terminal through an inverter 2a, and a flip-flop 2b whose positive phase is connected to its set terminal. It consists of a relay 2d whose output terminal is connected to one end through a driver 2c, and whose other end is connected to a power supply,
Contacts 2d', 2d'', and 2d of the relay 2d are inserted between the power supply and control signal lines r, s, and t for controlling the electric motor f, electrode k, and fuel pump h, respectively.

On the other hand, the water level detection section 3 is followed by a water supply control section 4 and an interlock circuit L, and the output terminal of the interlock circuit is connected to the reset terminal of the flip-flop 2b in the heating control section 2.

FIG. 2 is a block diagram showing the water level detection section 3, water supply control section 4, and interlock circuit L.

Regarding the water level detection unit 3 in the same figure, in comparison with the configuration shown in FIG. A simple-shaped communication pipe where water is directly supplied from the pipe n by a water supply pump W.
This is expressed by replacing n′.

The water level detection unit 3 includes a lower limit water level probe 3 disposed such that its tip is located at the lower limit water level L of canned water.
a, an upper limit water level probe 3b disposed so that its tip is located at the upper limit water level H of canned water, an underwater electrode 3c buried in water, an AC power source 3d whose one end is connected to the underwater electrode 3c, A first current detector 3e inserted between the other end of the AC power source 3d and the lower limit water level probe 3a, and a second current inserted between the other end of the AC power source 3d and the upper limit water level probe 3b. It consists of a detector 3f.

In the water supply control unit 4, the positive phase output terminal of the first current detector 3e is connected to one of its set terminals, and the positive phase output terminal of the second current detector 3f is connected to its reset terminal through the inverter 4a. The flip-flop 4b is connected to one end of the flip-flop 4b, and the positive phase output terminal of the flip-flop 4b is connected to one end of the flip-flop 4b through a driver 4c, and the other end of the relay 4 is connected to a power supply.
The contact 4d' of the relay 4d is inserted into the power supply line y of the electric motor v that drives the water pump W.

Furthermore, one end of a set switch 4f inserted between the power supply and ground through a resistor 4e is connected to another set terminal of the flip-flop 4b.
connected via g.

The water level change detection unit 5 includes monostable multivibrators 5a and 5b connected to the positive phase and complementary phase output terminals of the first current detector 3e, and the second current detector 3.
monostable multivibrators 5c and 5d connected to the positive phase and complementary phase output terminals of Consists of.

The interlock state storage section 6 consists of a flip-flop 6a whose one reset terminal is connected to the output terminal of an OR gate 5e, and whose other reset terminal is connected to a reset switch 6c inserted between the power supply and ground through a resistor 6b. The set terminal thereof is connected through a resistor 6d to a set switch 6e inserted between the power source and ground through a differentiating circuit 6f.

Further, the complementary output terminal of the flip-flop 6a is connected to the reset terminal of the flip-flop 2b in the heating control section 2. The set switch 6e and the set switch 4f in the water supply control section 4 are connected to a contact 4 in the power supply line y of the electric motor v.
It is linked to the water supply control start switch z inserted in series with d'.

The blow command display section 7 includes a driver 7a whose input terminal is connected to the positive phase output terminal of the second current detector 3f, and a lamp 7b following the driver 7a.

The interlock display section 8 consists of a driver 8a whose input terminal is connected to the positive phase output terminal of the flip-flop 6a, and a lamp 8b following the driver 8a.

The water level change detection section 5, interlock state storage section 6, blow command display section 7, and interlock display section 8 form an interlock circuit L.

FIG. 3 is a waveform diagram illustrating the main waveforms of the steam pressure detection section 1, the heating control section 4, the water level detection section 3, and the water supply control section 4. , the output signal of the first comparator 1b, or the positive phase output signal B of the first current detector 3e, and the output signal of the second comparator 1c,
Alternatively, the positive phase output signal C of the second current detector 3f and the positive phase output signal D of the flip-flop 2b or flip-flop 4b are shown in comparison.

Regarding the above configuration, first, the operations of normal heating control and water supply control will be explained as follows.

Now, the vapor pressure in water pipe b, that is, the vapor pressure in communication pipe n, decreases as steam is consumed (Fig. 3A,
a) When the lower limit vapor pressure P _L is reached (Fig. 3A,
b) Since the vapor pressure signal _S1 output by the pressure sensor 1a according to the vapor pressure is smaller than the lower limit set value _VL corresponding to the lower limit vapor pressure supplied from the reference voltage source 1d, the first The output signal of comparator 1b is inverted from "1" to "0" (Fig. 3 B, c),
The lower limit vapor pressure signal _SPL is supplied to the set terminal of flip-flop 2b. Then, flip-flop 2b is set (Fig. 3D, d), and relay 2d is set.
transitions to an excited state, and contacts 2d', 2d'', and 2d close.

Then, the blower g starts blowing air, the fuel valve h opens to supply fuel to the fuel injection rod j, and furthermore, the electrode rod k starts spark discharge, so the burner B shifts to the ignition state. .

In the ignition state, the vapor pressure increases (Fig. 3A,
e) Eventually, when the upper limit vapor pressure P _H is reached (the third
Figure A, f), this time, the vapor pressure signal S ₁ becomes larger than the upper limit set value V _H corresponding to the upper limit vapor pressure supplied from the reference power source 1e, so the output signal of the second comparator 1c It is inverted from "0" to "1" (Fig. 3C, g), and the upper limit vapor pressure signal _SPH is output.

This inverted signal from "0" to "1" is converted into an inverted signal from "1" to "0" by the inverter 2a, and is supplied to the reset terminal of the flip-flop 2b to reset it (FIG. 3). D, h).

Then, relay 2d shifts to the de-energized state and contacts 2d', 2d'', 2d open, so burner B
transitions to a non-ignition state.

In the non-ignition state, the vapor pressure decreases (Fig. 3A,
i), when the lower limit vapor pressure P _L is eventually reached (the third
A, b'), the first comparator 1b operates in the same way as before (Fig. 3B, c'), and the flip-flop 2
b is set again (Fig. 3 D, d'), and burner B
returns to the ignition state.

In this way, the intermittent control of burner B is repeatedly performed, and the steam pressure in the upper header c reaches the upper and lower limit steam pressures.
The pressure is maintained between P _H and P _L.

A period T1 during which the flip-flop 2b is set to " ₁ " represents a heating period, and a period _T2 during which the flip-flop 2b is set to "0" represents a heating stop period.

In exactly the same way, assuming that the canned water level detected by the water level detection unit 3 rises and falls as shown in Fig. 3A, when the canned water level reaches the lower limit water level L (Fig. 3A, b), The lower limit water level probe, which had been submerged up to this point, leaves the water surface, so the AC power supply 3d
A load circuit consisting of a first current detector 3e, a lower limit water level probe 3a, and an underwater electrode 3c connected to the probe 3a and the electrode 3c is cut off between the probe 3a and the electrode 3c. The current passing through the detector 3e is cut off.

Then, the output signal of the leveler 3e is inverted from "1" to "0", outputs the lower limit water level signal S _L (3B, c), and sets the flip-flop 4b (3D, d). ), the relay 4d shifts to the energized state, the contact 4d' closes, and the water supply pump W is started, thereby supplying water to the water pipe b, that is, the communication pipe n'.

When the can water level rising due to water supply reaches the upper limit water level H, the upper limit water level probe 3b, which had been away from the water surface up to this point, is submerged in water, so that conduction occurs between the probe 3b and the underwater electrode 3c, and the second Current begins to pass through the current detector 3f.

Then, the output signal of the current detector 3f becomes "0".
is reversed to "1", outputs the upper limit water level signal S _H (Fig. 3C, g), and resets the flip-flop 4b (Fig. 3D, h), so that the relay 4d shifts to the de-energized state. , the water supply pump W stops.

When the water supply is stopped, the canned water level drops (Fig. 3 A, i) and eventually reaches the lower limit water level L (Fig. 3 A, b'), and the first current detector 3e operates in the same manner as above. Then, the flip-flop 4b is set again (FIG. 3D, d') and water supply starts.

Thus, the intermittent control of the water supply pump W is performed separately and independently from the intermittent control of the burner B, and the can water level is maintained at a level between the upper and lower limit water levels H and L.

A period t1 during which the flip-flop 4b is set to " ₁ " represents a water supply period, and a period _t2 during which the flip-flop 4b is set to "0" represents a water supply stop period.

Next, the operation of interlock circuit L will be explained as follows.

First, when an operation is performed to start operation of the boiler, the feed water control switch Z is closed, enabling intermittent control of the feed water pump. At this time, in conjunction with the switch Z, the set switch 6e in the interlock state storage section 6 closes, and supplies the differential waveform as the water supply control start signal _S2 to the set terminal of the lip-flop 6a. 1" to store the interlock state, the complementary output signal of the flip-flop 6a becomes "0", and this "0" is received at the reset terminal as the interlock signal _S3 , and the heating control section 2 The flip-flop 2b inside is held at "0".

Therefore, during the period when the flip-flop 6a is "1", the flip-flop 2b remains at "0" and the relay 2d cannot be energized, so that the burner B
is kept non-ignited.

During this time, similarly, the set switch 4f is closed in conjunction with the water supply control switch Z, and the differential waveform as a trigger signal is supplied to the set terminal of the flip-flop 4b, and this is set.
d becomes excited, water supply starts, and the can water level rises.

This water supply continues until the can water level, that is, the water level in the communication pipe n' rises and the upper limit water level probe 3b is submerged.

Then, when the can water level that was below the lower limit water level rises and the lower limit water level probe 3a is submerged, as in the case of operation start operation immediately after blowing, the current in the first current detector 3e increases. As the passage starts, the complementary output signal of the detector 3e is inverted from "1" to "0", and the upper and lower limit water level signal S _L ' is supplied to the monostable multivibrator 5b. transitions to a metastable state.

On the other hand, when the water level between the upper and lower limit water levels rises and the upper limit water level probe 3b is submerged, as in the case of starting operation with the can water level maintained between the upper and lower limit water levels H and L, In this case, the complementary output signal of the second current detector 3f is inverted from "1" to "0", and the ascending upper limit water level signal S _H ' is supplied to the monostable multivibrator 5d to bring it into a stable state. Migrate.
And the monostable multivibrators 5b, 5d
Any “1” output during the metastable period passes through the orgate 5e and becomes the water level change signal S ₄
The signal is supplied to the reset terminal of the flip-flop 6a to reset it. Then, the flip-flop 6a clears the memory of the interlock state, and the interlock signal _S3 of "0" is reversed to "1" and disappears, so that the reset terminal of the flip-flop 2b in the heating control section 2 is set to "1". is supplied, the flip-flop 2b can be controlled by the upper and lower steam pressure limits S _PH and S _PL , and the inhibition of the heating operation for the burner B is lifted, and intermittent control of the burner is started.

Thus, only when the water level in the communicating pipe n' actually rises, in other words, only when the communicating pipe n' is not blocked, is the prohibition on the heating operation lifted and burner B capable of igniting. It is. Then, during the period when the heating operation is prohibited, that is, during the period when the flip-flop 6a is "1", the driver 8a in the interlock display section 8 becomes conductive in response to the positive phase output signal "1". , lights up the lamp 8b.

On the other hand, when starting operation when the can water level is rising and the upper limit water level probe 3b is submerged, the upper limit water level signal S _H is output from the second current detector 3f at the same time as the start of operation. Since the reset terminal of flip-flop 4b is kept at "0",
Despite the trigger signal from the set switch 4f, the flip-flop 4b remains at "0";
Therefore, water supply is never started.

As long as water supply is not started, there is no change in the water level of the can, and as a result, the water level change signal _S4 cannot be obtained, so the flip-flop 6a is left set to "1" at the start of operation, and the heating operation is delayed. The prohibition cannot be lifted and the boiler system will not actually start.

In this operating state, the second current detector 3f outputs "1" as the upper limit water level signal S _H from its positive phase output terminal as described above, and in response to this, the blow command display section 7 The driver 7a becomes conductive and lights up the lamp 7b.

When the operator confirms that the lamp 7b is lit, he opens the blowing tank q and blows out a portion of the canned water.

Then, the water level in the communication pipe n' falls, the upper limit water level probe 3b leaves the water surface, and the current passing through the second current detector 3f is cut off, so that the positive phase output signal of the detector 3f becomes " It is inverted from "1" to "0" and is supplied to the monostable multivibrator 5C as a descending upper limit water level signal S _H '', thereby shifting it to a quasi-stable state.

When the can water level further falls, the lower limit water level probe 3a also leaves the water surface, and similarly, the positive phase output signal of the first current detector 3e is reversed from "1" to "0", and the lower limit water level signal S _L '' is supplied to the monostable multivibrator 5a, causing it to transition to a metastable state.

And the monostable multivibrators 5a, 5
The "1" that c outputs during its metastable period passes through the OR gate 5e and becomes a water level change signal.
It is supplied as _S4 to flip-flop 6a and resets it.

Thus, in the above case, burner B will ignite only when the water level in the communicating pipe n' actually falls due to the blowing operation, in other words, only when the communicating pipe n' is not blocked. It is possible.

On the other hand, when the communicating pipe n' is blocked due to freezing, etc., the water level in the communicating pipe n' does not rise when water is supplied at the start of operation, and even when blowing is performed, the water level in the communicating pipe n' does not rise. Because I have nothing to do,
The OR gate 5e never outputs the water level change signal _S4 .

Since the flip-flop 6a, which is set at the start of operation, is not reset and kept at "1", the prohibition of the heating operation cannot be canceled.

In order to forcibly cancel the prohibition of the heating operation during maintenance and inspection, the flip-flop 6a may be manually reset by operating the reset switch 6c.

Next, referring also to FIG. 4, an embodiment of the second invention related to this invention will be described as follows.

FIG. 4 is a block diagram showing the configuration of an embodiment of the second invention, in which the communicating pipe n' has such a structure that its tip is located at a control water level C selected below the lower limit water level L. A control water level probe 3g is attached,
A third current detector 3h is inserted between the probe 3g and the AC power source 3d.

The water level detection unit 5 includes a monostable multi-channel multi-channel detector whose input terminal is connected to the positive phase and complementary phase output terminals of the third current detector 3g, and whose output terminals are connected to each input terminal of the OR gate 5e. vibrator 5f,
5g will be added.

Furthermore, an interlock signal generation section 9 is attached to the interlock circuit L, and the signal generation section 9
is, one input terminal of which is connected to the third current detector 3h.
A NAND gate (for "0" is a NOR gate) connected to the positive phase output terminal of the flip-flop 6a and whose other input terminal is connected to the complementary output terminal of the flip-flop 6a in the interlock state storage section 6; The output terminal of the NAND gate 9a is connected to the input terminal of the driver 8a in the interlock display section 8. Connected.

Other components are the same as those indicated by the same reference numerals in FIGS. 1 and 3.

In the above configuration, when the water level in the communication pipe n' rises at the start of operation and the control water level probe 3g, which was away from the water surface, becomes submerged in water, the first and second current detectors 3e, Similar to 3f,
The complementary output signal of the third current detector 3h is inverted from "1" to "0", and the ascending control level signal S _C ' is supplied to the monostable multivibrator 5g to shift it to a quasi-stable state. .

Furthermore, when the water level in the communication pipe n′ falls due to the blow operation, when the submerged control water level probe 3g leaves the water surface, the positive phase output signal of the third current detector 3h similarly changes. The signal is inverted from "1" to "0", and this inverted signal is supplied to the monostable multivibrator 5f as the descending control level signal S _C to shift it to a quasi-stable state.

And the monostable multivibrator 5f,
The "1" outputted by the monostable multivibrator 5g during the metastable period is supplied to the OR gate 5e together with the "1" outputted by the other monostable multivibrators 5a, 5b, 5c, and 5d to form the water level change signal _S4 .

Then, the flip-flop 6a, which is set by the water supply control start signal _S2 at the start of operation and stores the interlock state, is also reset by the water level change signal _S4 to clear the memory of the interlock state. The operation is the same as in the configuration shown in FIG.

On the other hand, when the can water level drops for some reason and remains below the control water level C, the control water level probe 3g remains away from the water surface, so the third current detector 3h continuously Outputs "0",
This "0" is supplied to one input terminal of the NAND gate 9a in the interlock signal generating section 9 as the control water level signal _SC .

Then, the NAND gate 9a outputs "1" regardless of the state of the complementary output signal of the flip-flop 6a that is supplied to the other input terminal, so the succeeding inverter 9b inverts this and outputs "1". ``0'' as the lock signal <sub>S3</sub> is supplied to the reset terminal of the flip-flop 2b in the heating control section 2 to forcibly hold it at ``0''.

Furthermore, an interlock state is stored in the flip-flop 6a, and the flip-flop 6a
is set, the complementary output signal "0" is supplied as the interlock state signal _S5 to the other input terminal of the NUN gate 9a, so that the gate 9a is in turn Regardless of the control water level signal S _C supplied to the input terminal,
Similarly to the above, the interlock signal _S3 is output to hold the flip-flop 2b at "0".

Thus, at the start of water supply, the flip-flop 6a
The interlock state stored in the can water level is also canceled when the can water level passes the control water level C, and in addition, not only when the flip-flop 6a stores the interlock state, but also when the can water level is The heating operation is also prohibited when it is detected that the water level has fallen below the control water level C.

Other operations are the same as those of the configuration of the present invention described based on FIGS. 1 to 3.

As described above, according to the present invention, the interlock state is memorized when the boiler starts operating, the heating operation is prohibited, and the change in the can water level accompanying the start of water supply or the blowing operation is detected, and the It is configured to clear the memory of the interlock state and cancel the inhibition of heating operation, so if the communication pipe becomes blocked due to freezing etc., the water level in the communication pipe remains fixed regardless of the water level in the can. When the interlock is held, the memory of the interlock is not cleared and the heating operation remains prohibited.Even if the connecting pipe is blocked, the heating operation is prohibited and the boiler is ensured to run dry. It has the excellent effect of preventing

Furthermore, according to a second invention related to the present invention, in addition to prohibiting the heating operation based on the memory of the interlock state in the configuration of the present invention,
Since the structure is configured to detect that the can water level is below the control water level selected below the lower limit water level and to prohibit the heating operation, in addition to the above-mentioned effects of the present invention, abnormally low can water It has the excellent effect of prohibiting heating operations at water level and more reliably preventing the boiler from running dry.

Furthermore, both this invention and the second invention connected thereto have the advantage of being simple in structure, since they are constructed by making use of the water level detection section that is essential for intermittent control of water supply in a boiler system. There is also.

[Brief explanation of drawings]

1 to 3 relate to an embodiment of the present invention, and FIG. 1 is a block diagram showing its configuration;
FIG. 2 is a block diagram showing the water level detection section, water supply control section, and interlock circuit, and FIG. 3 is a waveform diagram of the main parts. FIG. 4 is a block diagram showing the configuration of an embodiment of a second invention related to this invention. 1... Steam pressure detection section, 2... Heating control section, 3...
... Water level detection section, 4 ... Water supply control section, 5 ... Water level change detection section, 6 ... Interlock state storage section, 7
...Blow command display section, 8...Interlock display section, L...Interlock circuit.

Claims (1)

[Claims] 1. A communication pipe n that communicates the upper and lower ends of the water pipes and extracts a portion of the canned water, and detects that the water level of the communication pipe n is at the lower limit water level and outputs a lower limit water level signal S _L , The lower limit water level sensors 3a and 3e that output S _L ′ detect that the water level of the communication pipe n is the upper limit water level and output an upper limit water level signal.
The water level detecting means 3 consisting of upper limit water level sensors 3b and 3f that output S _H and S _H ', and the water supply pump W that supplies canned water to the water pipes in response to the lower limit water level signal S _L are started, and the upper limit water level signal A feed water control means 4 of intermittent control that stops the feed water pump W in response to S _H , a pressure sensor 1a that outputs a steam pressure signal _S1 corresponding to the steam pressure of the boiler, and a pressure sensor 1a that outputs a steam pressure signal _S1 corresponding to the steam pressure of the boiler; a first comparator 1b that detects that the lower limit set value corresponds to and outputs a lower limit vapor pressure signal _SPL ;
a second comparator 1c that detects that the vapor pressure signal _S1 is an upper limit set value corresponding to the upper limit vapor pressure and outputs an upper limit vapor pressure signal _SPH ; and a lower limit vapor pressure signal. In a boiler system equipped with intermittent control heating control means 2 that starts a heating device for heating the boiler in response to S _PL and stops the heating device in response to an upper limit steam pressure signal S _PH , Water level signals S _L , S _L ′ and upper limit water level signal S _H ,
A water level change detection means 5 detects a change in S _H ' and outputs a water level change signal _S4 , and stores an interlock state in response to a water supply control start signal _S2 and responds to a water level change signal _S4 . Then, the storage of the interlock state is canceled, and the interlock signal _S3 is sent to the heating control means 2 during the period in which the interlock state is stored.
Regardless of the lower limit vapor pressure signal S _PL ,
An interlock device for heating control in a boiler system, which is provided with interlock state storage means 6 for forcibly stopping heating device B. 2 Connecting the upper and lower ends of the water pipes to a communicating pipe n for extracting a portion of canned water, and detecting that the water level of the communicating pipe n is at the lower limit water level and outputting lower limit water level signals S _L , S _L ′ The lower limit water level sensors 3a and 3e detect that the water level of the communication pipe n is the upper limit water level and generate an upper limit water level signal.
The water level detecting means 3 consisting of upper limit water level sensors 3b and 3f that output S _H and S _H ', and the water supply pump W that supplies canned water to the water pipes in response to the lower limit water level signal S _L are started, and the upper limit water level signal A feed water control means 4 of intermittent control that stops the feed water pump W in response to S _H , a pressure sensor 1a that outputs a steam pressure signal _S1 corresponding to the steam pressure of the boiler, and a pressure sensor 1a that outputs a steam pressure signal _S1 corresponding to the steam pressure of the boiler; a first comparator 1b that detects that the lower limit set value corresponds to and outputs a lower limit vapor pressure signal _SPL ;
a second comparator 1c that detects that the vapor pressure signal _S1 is an upper limit set value corresponding to the upper limit vapor pressure and outputs an upper limit vapor pressure signal _SPH ; and a lower limit vapor pressure signal. In a boiler system equipped with intermittent control heating control means 2 that starts a heating device for heating the boiler in response to S _PL and stops the heating device in response to an upper limit steam pressure signal S _PH , Control water level sensors 3g, 3h that detect that the water level of pipe n is below a control water level selected below the lower limit water level and output a control water level signal S _C
is attached to the water level detection means 3, and further detects changes in the control water level signals S _C , S _C ′, lower limit water level signals S _L , S _L ′, and upper limit water level signals S _H , S _H ′ to generate a water level change signal. The water level change detection means 5 outputs the water level change signal _S4 , stores the interlock state in response to the water supply control signal _S2 , clears the memory of the interlock state in response to the water level change signal _S4 , and performs the interlock state. During the period in which the state is stored, the water level in the communication pipe n is controlled based on the interlock state storage means 6 which outputs the interlock state signal _S5 , the control water level signal _SC , and the interlock state signal _S5 . When the temperature is below the water level and when the interlock state storage means 6 stores the interlock state, the interlock signal _S3 is supplied to the heating control means 2 to generate the lower limit steam pressure signal.
An interlock device for heating control in a boiler system, which is provided with interlock signal generating means 9 for forcibly stopping heating device B regardless of S _PL .