JPH01127092A - Method for charging chemical agent in boiler - Google Patents

Abstract

PURPOSE:To prevent the carry-over of a chemical agent, by determining the dose of the chemical agent per the ON/OFF cycle of a cooling water pump by using a flow rate sensor and a microcomputer in combination and making it possible to automatically charge a proper amount of the chemical agent with due regard to the load of a boiler. CONSTITUTION:A water quality analytical result and the load of a boiler 1 are inputted to a control box 4 equipped with a computer by an input means. Next, when the water level in the boiler 1 is equal to or less than the operation start water level 8 of a water feed pump 2 after the start of the boiler 1, a signal is sent to the water feed pump 2 from the control box 4 and the water feed pump 2 is started. The feed amount of the water to the boiler 1 by the pump 2 is detected by a flow rate sensor 6 and this detection signal is sent to the control box 4. On the basis of the detected flow rate, the water quality analytical result and the load data of the boiler, the operating time of a quantitative type chemical agent pump 3 is set and the pump 3 is driven only for this set time to keep the ratio of a water feed amount and the dose of the chemical agent constant.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a boiler that implements a method of on-off operation of a feed water pump in order to maintain canned water in the boiler at a desired level. It also relates to a method of introducing chemicals to maintain a constant ratio between the water supply source and the amount of chemicals.

To be more specific, we use a microcomputer to register in advance the optimum amount of chemicals for the water quality and amount of water supplied, and then use a flow sensor to determine the realistic amount of water supplied to the boiler, which varies depending on the boiler load. This invention relates to a method of keeping the ratio between the water supply amount and the chemical input amount constant by detecting the amount of water and determining the operating period of the metering type chemical pump for each water pump on-oH cycle according to the detected value.

[Prior art] Conventionally, when a chemical pump is used to inject chemicals into a boiler that operates based on the level of canned water, the ratio of the amount of water fed to the boiler and the amount of chemicals input is kept constant. Generally, a method is adopted in which the chemical pump is operated while the water supply pump is operating, that is, the water supply pump and the chemical pump are operated on-o (f) at the same time.

In this method, if the pump maintains its initial capacity, the amount of water supplied and the amount of chemicals input are kept constant, and all that is left to do is adjust the discharge amount of the chemical pump according to the water quality.
If the capacity of either pump decreases, the ratio of the amount of water supplied to the amount of chemical input will change, and in the end, the discharge rate of the chemical pump will be adjusted to 11% depending on the water quality and the decrease in pump capacity.
It is necessary to

Generally speaking, when comparing the amount of water supplied and the amount of chemicals input, the amount of chemicals input is very small compared to the amount of water supplied. Therefore, for water supply pumps, high-pressure, large-capacity regeneration pumps or centrifugal pumps are used, and for chemical pumps, high-pressure, small-capacity, quantitative-type pumps with chemical resistance are used. Diaphragm pumps are typically used. However, in addition to the discharge volume of pumps used in boiler water supply systems changing due to the influence of the internal pressure of the boiler, the water supply pump capacity often decreases due to corrosion of chemicals due to backflow of can water, erosion, cavitation, etc. It's easy to do. On the other hand, diaphragm-type chemical pumps are fixed-capacity type and chemical-resistant, so the supply capacity does not decrease at all, and there are cases where pump maintenance is insufficient or the discharge performance is not properly understood. If this is not done properly, the time required for the water supply pump 7011 will become longer, and at the same time, the operating time of the chemical pump will also become longer, resulting in a situation where the amount of chemicals exceeds the amount of water supplied. This tendency is especially noticeable when the working pressure of the boiler is high, and as the capacity of the water supply pump decreases, the ratio between the amount of water supplied and the amount of chemical input changes significantly. Mechanical adjustment has disadvantages in terms of time and cost, and the reality is that it is generally unacceptable.

[Objective and Summary of the Invention j This invention turns on the water supply pump by using a pumping sensor and a microcomputer in combination.

This system determines the amount of chemicals to be fed per cycle and automatically injects the appropriate amount of chemicals while considering the boiler load.It is an excellent boiler chemical that eliminates the above-mentioned drawbacks of conventional techniques. It aims to cover the input method provided.

[Embodiments of the invention] The present invention will be explained below based on the drawings.

In the figure, (1) is a boiler, (2) is a water pump, (
3) is a metering type chemical pump, and this water supply pump (2)
A flow rate sensor (6) is provided in the middle of the water supply line (5) between the boiler (1) and the boiler (1). (7) a is
The water supply pump operation start water level detection rod (8) is the water supply pump operation start water level, (7'+b is the water supply pump stop water level detection rod, (9:i is the water supply pump stop water level).

(4) is equipped with a circuit that stores in advance the relationship between optimal chemicals for water quality and water supply amount, and the water level detection rod t7)a
, f7) Turn on and off the water pump (2) via b
Both units determine the operating time of the chemical pump (3) based on data regarding the three elements of water quality, flow rate from the flow sensor (6), and the load on the boiler (1), and issue an operating command (operation command) for the chemical pump (3). A microcomputer-built-in Pil+11 control box with the function of emitting a signal (!signal),
This control box includes a flow rate sensor (6), water supply pump (2), chemical pump (3), water level detection rod (7) a, (
7) Connected to b. Such a control box is further equipped with a 1nput mechanism (not shown) for inputting the water quality analysis results of the feed water and the boiler load.

Next, the operation of this invention will be explained. First, the water quality analysis results and the load (usually the operating pressure) of the boiler (1) are input into the control box (4) equipped with a computer using the 1nput mechanism. After starting the boiler (1), if the water level in the can is below the operation start level (8) of the feed water pump (2), a signal is sent from the control box (4) to the feed water pump (2), and the water pump ( 2) begins to operate. The realistic amount of water supplied to the boiler (1) is determined by the water supply line (
5) is detected by the flow sensor (6) provided in
This value is sent to box 1IIIi11 (4). There, the flow rate and water quality per catty result from the flow rate sensor ) operation time is set, and the chemical pump (3
), and after a set time, the chemical pump (3) stops regardless of whether or not the water supply pump (2) is in operation. On the other hand, when the water level of the boiler (1) reaches the feedwater pump stop water level (9), the feedwater pump is stopped separately from the chemical pump (3) by a command from the control box (4).

In a further preferred embodiment of the present invention, the water supply flow rate flowing through the water supply line (5) is controlled by turning the water supply pump on-
It is also possible to integrate the amount of chemicals based on the operating time per offl cycle, calculate a predetermined amount of chemicals for the flow rate at that time, and then inject the amount of chemicals during the next water supply cycle. , even when the boiler load fluctuates significantly, the water pump on = o[
By injecting a predetermined amount of chemicals into the water supply for each cycle, the ratio between the amount of water supplied and the amount of chemicals can be maintained accurately at all times.

[Effects of the Invention] As described in detail above, the present invention provides a control box equipped with a dispatch sensor and a microcomputer to determine the relationship between water supply 1, water quality, and boiler load to reduce the performance of chemical pumps and water supply pumps. By adding a function that multiplies the water supply time, the water supply volume can be adjusted even when the boiler load fluctuates. It is possible to maintain a more accurate ratio between the amount of chemical input and the amount of chemical input, and therefore, it is possible to prevent harmful effects caused by chemicals such as alkaline @ food and carryover due to excessive chemical input as in the past. In addition, the amount of chemical input can be controlled independently by the operating time of the chemical pump, which not only simplifies the overall system configuration, but also eliminates the need for a variable type chemical pump itself. It can be manufactured at a lower cost.

[Brief explanation of the drawing]

The drawing is a flow sheet relating to one embodiment of the present invention. (1)... Boiler (2)... Water supply pump (3)... Chemical pump (4)... Control box (5... Water supply line (6)... Flow rate sensor (7) a ...Water pump operation start water level detection rod (7i
b...Water pump stop water level detection rod (8)...Water pump operation start water level (9)...Water pump stop water level Patent applicant Miura Kogyo Co., Ltd.

Claims (1)

[Claims] The water supply pump (2) is turned on and off by detecting the canned water level.
The boiler (1) that implements the f-operation water supply method is equipped with a microcomputer that registers the relationship between water quality and the optimal amount of chemicals for the amount of water supplied, and a flow rate sensor (6) that measures the realistic amount of water supplied to the boiler (1). The water supply pump (
2) Chemical pump (3) per on-off cycle
Determine the operation time of the water supply pump, operate the chemical pump (3) separately from the water supply pump (2), and determine the flow rate of water flowing through the water supply line (5) based on the operation time per on-off cycle of the water supply pump. The system is characterized by adding an appropriate amount of chemicals according to the boiler load by integrating the amount, calculating a predetermined amount of chemicals for the current flow rate, and adding the amount of chemicals during the next water supply cycle. How to add chemicals to the boiler.