JPS5836247B2 - Multi-can type boiler plant automatic chemical feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention 1 relates to an apparatus for injecting a chemical into a boiler in a multi-can boiler plant.

Conventionally, in order to inject chemical liquid into the boiler in a two-can type boiler plant, an on-off valve is installed in the branch pipe connected from the chemical liquid supply pump to each boiler, and by operating the on-off valve, it is possible to selectively inject chemical liquid into the boiler. A chemical solution is being injected into the area.

However, the opening/closing valve may not be able to close completely due to dust being trapped, resulting in a slight gap.71
In such a case, there is a possibility that the minute pressure difference between the two cans will overcome the valve resistance and the chemical solution will be injected into another container that should not be injected.

If this happens, the water quality in the area where it should be injected will not be corrected11, and an excessive amount of chemical solution will be injected into other areas that do not need to be injected.

Therefore, the lift of the above-mentioned on-off valve is checked using a limit switch, but limit switches cannot easily detect minute gaps caused by entrapment of dust, etc.

It is difficult to detect when the on-off valve is not opened due to a failure even after the on-off valve has been opened.

Therefore, the present invention provides a multi-can boiler plant automatic chemical dosing device that solves such problems, and is characterized in that one end is connected to a chemical dosing tank and the other end is connected to a plurality of cans. A chemical solution supply pipeline is provided which is branched and the end of each branch pipeline is conveyed to each main valve of a plurality of boilers, and each of the branch pipelines is provided with an on-off valve, and the chemical solution in the chemical solution supply pipeline is provided. A pump is interposed in the vicinity of the tank, and a first pressure switch that operates at a pressure equal to or higher than the discharge side pressure when the pump is operated with the discharge side blocked is installed at an appropriate place between the pump and the on-off valve in the chemical supply pipeline. , a second pressure switch that operates at a pressure equal to or lower than the normal operating pressure of the boiler, and if the first pressure switch does not operate even after a predetermined short period of time after pump operation is started with the on-off valve closed, the on-off valve is activated. An alarm device is installed that issues a warning if the first pressure switch does not operate even after a predetermined short period of time has passed after blockage, or if the second pressure switch does not operate even after a predetermined short period of time after opening the on-off valve during pump operation. There is a particular thing.

According to this structure, even though the on-off valve is closed, when an IJ leak occurs due to encroachment of dust, the first pressure switch does not operate, and the alarm device is activated after a predetermined short period of time. is activated to warn of an abnormality.

Therefore, it is possible to prevent an accident in which the chemical solution is injected into a boiler other than the predetermined boiler.

If the broken on-off valve is not opened due to a malfunction of the on-off valve despite being opened, the second pressure switch will not operate and the alarm will be activated after a predetermined short period of time to detect an abnormality. This is a warning.

Therefore, failure of the on-off valve can be easily detected, and an accident in which the chemical solution is not injected into a predetermined boiler can be prevented.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1 and 2 are boilers, 3 is a chemical tank;
is pipe line 4, bomb 5. Pipe line 6, and branch pipe lines 7, 8
The water is communicated to the main valves 15 and 16 of the boilers 1 and 2 via.

Both branch lines 7, 8 are provided with on-off valves 9, 10, and the on-off valves 9, 10 and 9 are also provided with a first pressure switch 11 and a second pressure switch 12 on the line 6 on the pump 5 side. ing.

Reference numeral 17 is a pump discharge valve, and reference numeral 18 is an alarm device that is activated based on input signals from the first and second pressure switches 12.

Here, the normal operating pressure of boilers 1 and 2 is 75 kg/c1F.
12G, and the discharge side pressure with the discharge side of the pump 5 closed is 100 kg/cIrI2. G, the first pressure switch 11 is turned on when the discharge side pressure of the pump 5 is in the discharge side closed state, that is, i) 100 kg/cIfi2G or more, and the second pressure switch 12 is turned on when the pressure of the boilers 1 and 2 is exceeded. Set to turn ON at normal operating pressure of 75 kg/crl G or less.

However, the second pressure switch 12 is the same as the first pressure switch 1.
It operates after 1 is activated.

Reference numeral 13 is a relief valve provided between the pipes 4 and 6 in parallel with the pump 5, and is capable of releasing pressure of 10 kg/ari'G or more.

Next, we will explain the operating procedure during drug injection.

First, when injecting into the boiler 1, a case will be explained in which the case is in normal condition and there is no leakage in both the on-off valves 9 and 10.

Usually, the pump 5 is started with both on-off valves 9 and 10 closed.

As a result, the pressure in b1 pipe 6 is 100 kg/crIL2G
When the pressure is reached, the first pressure switch 11 is turned on.

After that, when the on-off valve 9 is opened, the pressure inside the pipe 6 drops to 75 k9/Cm"G, which is the same pressure as the pressure inside the boiler 1, due to the communication between the pipe 6 and the boiler 1. The second pressure switch 12 is turned on, and the first pressure switch 11 is turned off.

In this state, injection into the boiler 1 continues, and when a predetermined amount is injected, the on-off valve 9 is closed.

As a result, the pressure inside pipe 6 is 100 kg/CrfL2G.
As soon as the first pressure switch 11 is turned on,
The second pressure switch 12 is turned off.

After this, the pump 5 is stopped and the injection work is completed.

The solid line in FIG. 2 shows the pressure change in the pipe line 6 during the above-mentioned normal injection of the chemical liquid. (2) indicates the pressure when the on-off valve 9 is opened to inject the chemical solution, (2) indicates the pressure when the on-off valve 9 is closed after injection, and (2) indicates the pressure when the pump is stopped.

Next, if there is a leak in either the on-off valves 9 or 10,
The detection means will be explained.

That is, when the pump 5 is started with both on-off valves 9 and 10 closed, if there is even a slight leak in at least one of the on-off valves 9 and 10, the pressure in the pipe line 6 will decrease to 10.
0 kg/cm2G, for example, as shown by the broken line section I' in Figure 2, 75 k, @/c11L2G not
1, and the first pressure switch 11 becomes OFF.

However, even after a predetermined short time has elapsed after pump 5 is started, the first
If the pressure switch 11 is not turned on, a signal is input to the alarm device 18, and the alarm device 18 issues a warning.

Through this alarm, it is possible to know the occurrence of an abnormality in the on-off valves 9 and 10, and to emergency stop the pump 5 and fully close the main valves 15 and 16 to prevent unnecessary injection of excessive chemical into the boilers 1 and 2. can be prevented.

Next, when detecting which of the on-off valves 9 and 10 is abnormal, the main valves 15 and 16 may be opened alternately.

With this, for example, when a warning is issued when the main valve 15 is opened, it can be known that a leak is occurring from the on-off valve 9.

Next, when the on-off valve 9 is closed to the injection liquid of the drug solution, the on-off valve 9
If the blockage is incomplete, the pressure inside the pipe 6 will be 100 kg/
cTL2G is not reached, and as shown in the broken line section ■' in Figure 2, 7 5ky/crIr! As a result, the first pressure switch 11 does not turn on, and the second pressure switch 12 remains on.

However, even after a predetermined short period of time has passed after the on-off valve 9 is closed, the first
If the pressure switch 11 does not operate, the alarm device 18
A signal is input to the alarm device 18, and a warning is issued from the alarm device 18.

Next, when the on-off valve 9 is not opened even though the button is pressed to open the on-off valve 9 while the pump 5 is running, the pressure inside the pipe 6 becomes 11 of 100 kg/dG. The second pressure switch 12 is set to 1 when it is OFF.

If the second pressure switch 12 does not operate even after a predetermined short period of time has passed after opening the on-off valve 9, a signal is input to the alarm device 18, and the alarm device 18 issues a warning.

In addition, although the above-mentioned embodiment explained the case of a two-can system, the present invention is similarly applicable to a case of three or more streets.

As described above, according to the present invention, even though the on-off valve is closed, when a leak occurs due to encroachment of dust, the first pressure switch does not operate, and after a predetermined short period of time has elapsed. An alarm device is activated to warn of an abnormality.

Therefore, it is possible to prevent an accident in which the chemical solution is injected into a boiler other than the predetermined boiler.

If the first on-off valve is not opened due to a malfunction in the first on-off valve, the second pressure switch will not operate and the alarm will be activated after a predetermined short period of time to detect an abnormality. This is a warning.

Therefore, failure of the on-off valve can be easily detected, and an accident in which the chemical solution is not injected into a predetermined boiler can be prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with Figure 1 being a piping diagram and Figure 2 being a piping diagram.
The figure is a graph showing pressure changes within the pipeline. 1, 2... Boiler, 3... Chemical tank, 5... Pump, 6... Piping, 7, 8
...Branch pipe line, 9,10... Open/close valve,
11...First pressure switch, 12...
2nd pressure switch, 18. River...alarm device.

Claims (1)

[Claims] 1. A chemical liquid supply pipe is provided, one end of which is connected to a chemical liquid lamp, the other end of which is branched into a plurality of pipes, and the end of each branch pipe is connected to each main valve of a plurality of boilers. An on-off valve is provided in each of the branch pipes, a pump is interposed near the chemical tank in the chemical supply pipe, and a pump is installed at an appropriate place between the pump and the on-off valve in the chemical supply pipe when the discharge side of the pump is closed. A first pressure switch that operates at a pressure equal to or higher than the roaring pressure of the discharge side pressure phase during operation, and a second pressure switch that operates at a pressure equal to or lower than the normal operating pressure of the boiler are provided, and after the pump operation is started with the on-off valve closed, If the first pressure cass inch does not operate even after a predetermined short period of time has elapsed, or if the first pressure cass inch does not operate even after a predetermined short period of time after the on-off valve is closed, or when the first pressure cass inch does not operate even after a predetermined short period of time has elapsed after the on-off valve is closed, or when the on-off valve is opened during pump operation, An automatic chemical feeder for a multiple can type boiler plant, characterized in that it is provided with an alarm device that issues a warning if the second pressure switch does not operate even after a period of time.