JPH0711296Y2 - Boiler chemical injection device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an improvement of a chemical injection device for preventing boiler body corrosion, scale adhesion, and the like.

[Conventional technology]

Generally, in a boiler system, as water treatment for water supply management, external treatment of hardness is removed by a water softener, and silica is removed by injection of a chemical solution and dissolved oxygen, etc. that causes corrosion of the can body is removed. In-can treatment is adopted,
Highly efficient operation and improved durability have been achieved.

Among them, as the in-can treatment, a method of injecting a chemical liquid at a constant ratio with respect to the amount of water supplied by a chemical liquid injection device (hereinafter abbreviated as chemical injection device) that operates in conjunction with a boiler water supply device is adopted. Has been.

[Problems to be solved by the device]

By the way, in the boiler system, in order to prevent the scale from adhering and to minimize the corrosion of the can body, it is said that the pH value of the can water is preferably adjusted within the range of 11.0 to 11.8.

Further, the can water is gradually concentrated with the operation of the boiler system, and the pH value also rises, which causes problems such as carryover and alkali corrosion of the can body. for that reason,
When such a canned water concentration state is reached, it is necessary to blow the canned water and supply new water.

Therefore, in the above-mentioned chemical injection device, if the amount of the chemical liquid to be injected into the water supply is within the above-mentioned pH value range, the can water will be concentrated early, so it is necessary to frequently perform the blowing operation, while the chemical liquid If the amount is suppressed to a small amount, it takes a long time for the pH value to reach the above range due to the concentration of water in the can, so that there arises a problem that scale adhesion and can body corrosion are accelerated.

Therefore, by injecting a relatively large amount of chemical liquid at the beginning of water supply,
Various chemical injection devices have been proposed and implemented in which the pH value is adjusted to the above-mentioned range or near the lower limit thereof, and a small amount of chemical liquid is injected into the supply water supplied during the operation of the boiler.

Examples of this type of chemical injection device are disclosed, for example, in JP-A-59-24101, JP-A-60-253702, JP-A-60-263001, and JP-A-62-155410. However, in all of them, the control of the chemical liquid injection pump is complicated, and it is necessary to provide a chemical liquid injection means in addition to the chemical liquid injection pump (hereinafter abbreviated as chemical injection pump). , Has a factor that prevents the cost reduction of the entire boiler system.

Particularly in small-capacity ones such as a simple boiler system, the cost increase due to such a chemical injection device occupies an important ratio, and therefore an inexpensive chemical injection device capable of solving the above-mentioned pH value problem is required. .

[Means for Solving the Problems]

This invention has been made in order to solve the above problems, by connecting a chemical injection line in the middle of the water supply line, in a chemical injection device for a boiler configured to interlock the water supply pump and the chemical injection pump, For a boiler equipped with a device that operates the chemical injection pump at the same time as the operation of the first water supply pump after the boiler starts operating, and thereafter operates once every predetermined number of times of operation of the water supply pump. It is a chemical injection device.

[Action]

When using the chemical injection device for a boiler according to this invention,
After starting the operation of the boiler, the chemical injection pump is interlocked at the time of the first operation of the water supply pump to inject a high-concentration chemical solution into the boiler, and thereafter every predetermined number of operations of the water supply pump, for example, 2
It is possible to equivalently inject a low-concentration drug solution by interlocking the drug injection pump once every three times.

〔Example〕

FIG. 1 shows an embodiment of a chemical liquid injector for a boiler according to the present invention.

In the drawings, (1) is a boiler, (2) is an operation box of the boiler (1), (3) is a water supply line connecting the boiler (1) and a water supply tank (4), and (5) is a water supply line. A water supply pump connected in the middle of (3), (6) is a check valve (8) from the chemical liquid tank (7) to the water supply line (3)
(9) is a chemical injection pump connected in the middle of the chemical injection line (6), (10) is a water level detector for detecting the water level in the boiler (1), and (11) ) Turns on the water supply pump (5) by the signal from the water level detector (10)
Although the respective water supply control devices for performing -OFF control are shown, these components are publicly known and therefore detailed description thereof is omitted.

The control device (12) according to this device is a boiler (1).
The operation start signal is received from the operation box (2) of the above, the operation control signal of the water supply pump (5) is received from the water supply control device (11), and the chemical injection pump (9) is based on these two signals. The operation control signal is transmitted to the.

As the operation start signal of the boiler (1), for example, the operation switch (power switch) of the boiler (1) is turned on.
Alternatively, a signal from a switch means selectively switched by the operation of the water supply pump (5) when the boiler (1) is orbited can be used.

The control procedure of the chemical injection pump (9) in the control signal (12) is as follows. That is, when an operation start signal is received from the operation box (2) and an operation control signal for operating the water supply pump (5) is received from the water supply control device (11), the medicine is supplied at the same time as the operation control signal is received. An operation signal is output to the injection pump (9) to operate the chemical injection pump (9). After that, when the water level detector (10) detects that the water level in the can reaches a predetermined level, the water supply control device (11) stops the water supply pump (5), and the control device (12) causes the water supply The chemical injection pump (9) is stopped by detecting the stop of the pump (5).

After that, the control device (12) is the water supply pump (5).
The operation of the water supply pump (5) is preferably 2-3
Each time it is operated, the chemical injection pump (9) is interlocked once to operate.

The operation interval between the water supply pump (5) and the chemical injection pump (9) in the case of such control is determined as follows, for example, and set in the control device (12).

First, determine how much chemical solution to inject to the first water supply after the boiler (1) can water is completely blown, and to determine the chemical solution concentration at this time and the chemical solution concentration for the subsequent supply water. The above-mentioned operation interval is calculated by using the ratio as the ratio of the number of times of operation of the water supply pump (5) and the chemical injection pump (9).

The above-mentioned operation interval can be set based on the amount of chemical liquid with respect to the amount of water supplied to the boiler (1) during steady operation.

For example, first determine the chemical solution injection concentration during steady operation, and then determine how many times the chemical solution injection concentration during steady operation during initial water supply. The number of operations of the water supply pump (5) with respect to the chemical injection pump (5) is the above-mentioned magnification, and this is the above-mentioned operation interval.

Specific examples of the control of the water supply pump (5) and the chemical injection pump (9) are shown in FIGS. 2 (a) and 2 (b), which will be described below.

FIG. 2 (a) shows a control example in which the chemical injection pump (9) is operated once each time the water supply pump (5) is operated twice, and FIG. 2 (b) is a water supply pump ( 5) shows a control example in which the chemical injection pump (9) is operated once every three operations, and the chemical concentration of the can water at the initial water supply is 2 respectively.
It is designed to be doubled and tripled.

Therefore, according to this devised device, since the chemical concentration of the boiler can water in the boiler (1) can be made several times higher than the concentration of the injected chemical in the normal state from the start of the operation after the blow, the low concentration at the start of the operation can be achieved. Various problems such as scale adhesion and can body corrosion due to pH value can be avoided, and chemical pump (9) is used during steady operation.
Since the water supply pump (5) is interlocked once every predetermined rotation of the water supply pump (5), the chemical solution is equivalently injected at a low concentration, and the time until the overconcentration state of the can water is Since it can be set longer than when using a general chemical injection device that operates the chemical pump in complete coordination, it eliminates the problems of scale adhesion and can body corrosion described above, and eliminates boiler can body corrosion for a long period of time. You can slip off.

[Effect of device]

As described above, according to the chemical liquid injector for a boiler according to the present invention, the chemical injection pump is operated at the first operation of the water supply pump after the operation of the boiler is started, and thereafter the water supply pump operates a predetermined number of times. Since the chemical pump is operated once each time, even if the boiler operation is started after all the blow, a large amount of chemical solution is injected into the initial water supply to quickly raise the can water to the desired pH value. After that, the injection interval can be extended to extend the time until the overconcentration state of the can water. Therefore, not only can the can body corrosion and scale adhesion be prevented immediately after the boiler is started, but its preventive effect is maintained for a long time because the can water blowing interval is widened.

Further, according to the chemical injection device for a boiler according to the present invention, the blow interval can be widened even though the can water has a predetermined pH value from the initial stage of operation as described above. In addition, the thermal efficiency in operation can be improved, and the advantages such as the simple structure and low cost can be obtained even though the above-mentioned extremely useful effects are practically exhibited.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a chemical liquid injector for a boiler according to the present invention. 2 (a) and 2 (b) are timing charts for explaining an example of the operation of the boiler chemical liquid injector according to the present invention. (1) …… Boiler, (3) …… Water supply line (5) …… Water supply pump, (6) …… Medication injection line (9) …… Medication injection pump, (12) …… Control device

Claims (1)

[Scope of utility model registration request] 1. A chemical injection line (6) is connected in the middle of the water supply line (3) to provide a water supply pump (5) and a chemical injection pump (9).
In the boiler chemical liquid injector configured to interlock with, the chemical injection pump (9) is operated at the same time as the operation of the first water supply pump (5) after the boiler (1) is started, and thereafter. Is a chemical injection device for a boiler, comprising a control device (12) which operates so that the water supply pump (5) operates once every predetermined number of operations.