JPH0631289Y2 - Water level controller for boiler with single electrode - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention uses a single water level detecting rod.
Water level control system for boilers that controls water supply pumps
About the. A water surface controller for a boiler of this type is disclosed in
It is known from Japanese Patent Publication No. 51-41195. According to this publicly known example
For example, the water supply pump can be controlled with a few water level detection rods.
Want to miniaturize the control box as much as possible, reduce cost
Suitable for small capacity boilers with large demands
It is a thing. [0003] The present invention is, however, various Research
As a result of repeated research and experiment, the inventors
Water level control was found to have the following problems. One
Changes depending on the boiler output (steam usage)
When the control width changes and the water pump starts and stops frequently
Another issue is that the upper point of the water level control range is the seed.
It is easy to change due to various factors, but
You will be greatly affected by this, and you will get a stable output.
The problem is that it is difficult to obtain. That is, the former problem will be described in detail below.
Note that the conventional control is time t1 after the water level reaches the water level detection rod.
After that, the water supply pump was stopped and the water level fell below the water level detection rod.
And to drive the water supply pump immediately. Such a system
If the boiler output increases, it depends on the time t1.
The control width, that is, the upper point of the water level control width, becomes low, and conversely
If the output level of the
It On the other hand, the lower point of the control width has no time factor, that is,
Since it is fixed, it remains constant even if the boiler output increases or decreases.
As a result, the water level control range becomes wider depending on the boiler output.
When it becomes narrow due to fluctuations such as
Frequently starts and stops the water supply pump (ON-OFF),
There is a problem that the life of the water pump etc. is shortened. The latter will be described in general.
The water level control range of the ra
(If the water level is too low, overheating will occur.)
The upper point is defined from the subject (If the water level is too high, the dryness will be low.
As a result, the desired water level control width is the structure of the can body.
And uniquely determined by combustion conditions. This background
If the water level control like the conventional example is performed based on
A problem arises. That is, the upper point of the water level control width is the set time t1.
The lower limit of the water level control width is defined by
When the water level control width is set to be approximately
In this case, the control width is configured only by the set time t1.
There is no choice but to lengthen the fixed time. However, the set time t1
The upper point defined by is the fluctuation of the capacity of the water supply pump.
(Pump capacity decreases over time) and water supply pressure
Because it changes up and down due to factors such as fluctuations in (head pressure),
Since the set time t1 is long, the amount of change in the conventional control is
Becomes large and it becomes difficult to obtain stable output.
There is a problem called. The purpose of this invention is to solve these problems.
The object is to provide a water surface control device for a boiler. A water surface control device for a boiler according to the present invention is arranged at a water surface control portion of a boiler.
Water control box and insert in this water control box
Equipped with a water surface detection rod
In the one that controls the pump, the water level is the water level detection rod
It is supplied after t12 after the set time from when the tip reaches the set level.
The water pump was stopped and the water level dropped below the set level.
Start the drive by the water supply pump after the set time t11 from time
It is characterized by having a timer for the water supply pump . According to the above means, the water level is set on the water level detecting rod.
After reaching the level, the water supply pump stops after the set time t12
However, set the water level below the set level of the water level detection rod.
Water supply by the water supply pump is started after the fixed time t11. Servant
When the boiler output is large, the set time t12
The upper limit of the water level control width specified by
The lower point of the water level control width defined by t11 also falls,
When the boiler output is low, the set time t12
The upper limit of the defined water level control width rises, and the set time t11
The lower limit of the water level control range defined by
Thus, the water level control width is controlled to be constant. The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a circuit diagram illustrating a water surface control device according to the present invention, in which (1) is a water surface control box. Inside the water surface control box (1), as shown in the figure, one water surface detection rod (2) is inserted in an insulated state from the box (1). Furthermore, the water surface control box (1) is connected to an AC power supply (3) for water surface detection and a water surface detection relay X, and the AC power supply (3) is
It also has the function of preventing the polarization of the water surface detector. WP is a switch for a water supply pump, and is a BM
Is a switch for a burner motor. T1 is a timer for a water supply pump of so-called time-delayed time-delay type, which closes its contact after being excited for a certain time t11, and keeps its contact for a certain time even when it is non-excited. It has a mechanism that opens after t12. Further, T2 is a so-called timed operation instant return type burner motor timer, which has a mechanism for opening its contact after being excited for a certain time t2 and for momentarily closing the contact when it is de-excited. Have The device of the present invention comprises the above-mentioned means. First, at the time of starting the boiler as shown in the figure (that is, when the water is short), the water level detection relay X is in the reset state, and the timers T1 and T2. Is excited to activate the contact, and the water supply pump switch WP operates to supply the water supply pump (not shown).
Water supply starts at the same time, while the burner stops combustion (standby). By the way, the water level of the boiler gradually rises
When the tip of (2) (setting level (4)) is reached, the water surface detection relay X is activated. Therefore, the timers T1 and T2 are de-energized, the timer T1 is restored after a certain time t12 has elapsed (water supply is stopped), and T2 is instantly restored (burner combustion is started). Since the timer T1 is of the time-delaying operation time-delaying type as described above, its contact can be closed until the set time and then opened. That is, the water supply pump switch WP operates until the set time t12 and then stops. On the other hand, since the timer T2 is of the timed operation instant return type, the contact is instantly closed upon return.
Therefore, the burner motor switch BM immediately operates.
That is, the combustion of the burner (not shown) starts immediately when the timer T2 is restored. Then, when the water level once risen again becomes below the tip of the water surface detecting rod (2) (setting level (4)) or less, the water surface detecting relay X returns again. That is, both timers T1 and T2 are excited. The contact of the timer T1 is closed after the time t11 has elapsed to some extent because the contact of the timer T1 is of the timed type, and the water supply pump switch WP is activated again. On the other hand, the contact of the timer T2 continues to close until the set time t2 is reached and then opens (operates) because the contact of the timer T2 is a timed operation type, so the burner motor switch BW continues to operate until the set time t2. Therefore, the burner also continues to burn until the set time t2 is reached. Next, the function and effect of the above embodiment will be described.
To do. Water supply pump by the above-mentioned water supply pump timer T1
Output from the boiler to the load
The change in the water level control width W due to the fluctuation of the boiler output
explain about. Water pump when the boiler output is high
Since the input amount due to
Upper point W of water level control width W defined by constant time T12
1 becomes low and the water level is defined by the set time T11
The lower point W2 of the control width W is a button when the water supply pump is stopped.
Since the boiler output amount is determined only by the amount of the boiler output amount,
When there are many, the amount of water level drop per unit time increases, so
As a whole, the water level control width is controlled to a constant side.
It When the boiler output is small, the upper point W1 is
As the water level control width W increases, the lower point W2 also increases.
Similarly, it is controlled to a constant side. When the water level control width W is set to be substantially constant,
Upper point W1 defined by constant time t12 and set time t11
The water level control width W is composed of the lower point defined by
Therefore, the set time t12 can be shortened compared to the conventional example, and
It is possible to reduce the fluctuation amount of the water level control width due to various fluctuation factors.
It That is, water supply pump capacity, water supply pressure (head pressure), steam
If the pressure changes, the upper point W1 changes, but the setting
Since the time t12 can be shortened, the fluctuation amount of the water level control width is
It is possible to obtain a stable output . Furthermore, when controlling the water supply of the boiler, it is generally necessary to control the amount of water supply and to stop the combustion of the burner in order to prevent overheating of the boiler when the water level drops below the specified water level. is there. In order to achieve this, conventionally, the water supply control level and the burner stop level have been set at different positions to prevent mutual interference. However, in this embodiment, the water supply control level and the burner stop level are set to the same level, and a temporal element is added (the water supply pump timer is the timed operation timed return type, and the burner motor timer is the timed operation instantaneous return type). It is possible to prevent mutual interference only. According to the present invention constructed as above.
For example, the water level control width should be adjusted regardless of fluctuations in the boiler output.
It can be controlled to the fixed side, frequent start and stop of the water supply pump can be prevented,
Extend equipment life, improve durability and reliability
it can. In addition, when the output of the boiler is large, the water level control width
The low point of is low and high when it is low, so it prevents overheating
Has a great effect on. Furthermore, the stable output of the boiler is greatly affected.
Conventionally, the set time t12 that determines the upper limit of the threshold level
Can be shortened, and stable output can be obtained.
Be effective.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing a preferred embodiment of a single-electrode water surface control device according to the present invention. DESCRIPTION OF REFERENCE NUMERALS (1) water control box (2) water level detection rod (3) AC power W feedwater control width W1 upper point W2 lower point T1 feedwater pump timer t11 water supply start time t12 the water supply stop time

Claims (1)

[Claims for utility model registration] Water surface control part of boiler
The water level control box and the water level control box
With a water surface detection rod inserted in the
When controlling the water supply pump by
After a set time from when the set level at the tip of the water surface detection rod is reached
After t12, the water supply pump is stopped and the water level is below the set level.
Driven by the water supply pump after the set time t11
A water surface control device for a boiler with a single electrode, which is equipped with a timer for a water supply pump that starts operation .