JPH04306403A - Controller of forced once-through boiler - Google Patents

Abstract

PURPOSE:To maintain the degree of enrichment of the boiler water at a suitable level continually by regulating the volume of the supply water and the volume of the discharged separated water. CONSTITUTION:In the constitution of a forced once-through boiler that is provided with water tubes more than one, a burner 2, a supply water pump 3, and a separator 5, the above mentioned separator is provided with a separated water enrichment detection sensor 10, and for an operation control unit 11 of the above mentioned supply water pump, a controller 13 is provided which judges the output of the above mentioned sensor and acts to instruct an increase or decrease of the supply water volume according to the separated water enrichment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device effective for maintaining the concentration of canned water in a forced once-through boiler at an appropriate level.

0002

[Prior Art] In a forced once-through boiler consisting of a monotube, as shown in Fig. 1, water introduced into a water tube (21) is heated by a burner (22), and the state changes from liquid phase to gas phase. It becomes post-steam and is supplied to the desired location, but a part of it is separated as concentrated water (saturated water) and sent to the steam supply line (
28). That is, the separator (25) provided at the outlet end of the water pipe separates droplets and impurities contained in the generated steam, and these are removed through the discharge line (26). In this case, the burner (2
2) and the water supply pump (23) are configured to operate ON-OFF in conjunction with the load (amount of steam used), and the amount of water supplied by the water pump per unit time is determined by the relationship with the amount of combustion. Therefore, it is kept roughly constant.

[0003] In the above-mentioned method, it is difficult to set the discharge amount of separated water, especially to control the ratio of the former to the amount of evaporation, and if it is too large, it will lead to heat loss and reduce boiler efficiency. (Fuel loss). Conversely, if the amount of separated water discharged is too small, the water pipe (
21) The amount of water supplied into the tank also decreases, and the steam becomes too hot in the water pipe evaporation section, causing impurities in the water supply to condense and stick, causing damage to the water pipes.

[0004] As described above, when operating a forced once-through boiler, correctly controlling the amount of separated water discharged relative to the amount of evaporation is an important control element, but it is difficult to overcome with conventional methods. , a forced once-through boiler that can maintain the concentration of canned water at an appropriate level.
It hasn't appeared yet.

[0005]

[Problems to be Solved by the Invention] This invention solves the conventional problems by detecting the concentration of canned water and controlling the amount of water supplied to the water pipe so that it is maintained at a predetermined value. This is the solution.

[0006]

[Means for Solving the Problems] That is, the present invention provides a forced once-through boiler comprising one or more water pipes, a burner, a water supply pump, and a separator, in which a sensor for detecting the concentration of separated water is provided in the separator. and a control device that acts on the operation control unit of the water supply pump to determine the output of the sensor and instruct the water supply amount to increase or decrease according to the concentration of the separated water. There is.

[0007]

[Operation] According to the above configuration, the concentration level of the separated water in the separator is continuously detected by the concentration detection sensor, and the output of this sensor is determined. For example, when the concentration level of the separated water is high, The amount of water supplied can be appropriately controlled according to the actual concentration so that the amount of water supplied increases, and the concentration of canned water can always be maintained at an appropriate value.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the figure, (1) and (1') indicate water pipes that can be used alone or in combination in any form. (2) is a heating burner, (3)
is a water supply pump, and this pump is basically configured to turn on and off depending on the internal pressure of the accumulator (6). (12) is a pressure sensor, and (13) is a control device. The burner (2) and the water supply pump (3) are normally provided to operate in conjunction with each other, and (15)
When there is no water flow, the flow sensor indicated by
They are designed to stop in synchronization with each other to prevent dry firing.

The water supply pump (3) used here is equipped with a driving motor (4) and a control unit (11) that controls the rotation speed of this motor, and is capable of changing the amount of water supplied per unit time. Can be done. As an example of such a method, in addition to motor rotation speed control, other methods can also be used.

A separator (5) is connected to the outlet end of the water pipe (1) to separate droplets and impurities in the generated steam, and this separator is equipped with a concentration detection sensor (5). 10) is installed. (13) is a control device that discriminates the output signal of the sensor and issues a command to the control unit (11) when the degree of concentration of the separated water is high, so as to direct the water supply pump ( 3) Acts as if driving.

Reference numeral (14) is a separated water discharge means, such as a solenoid valve, which discharges the separated water accumulated in the separator through a discharge line (16) as appropriate. At that time, install a water level sensor (not shown) on the separator (5).
Attach the solenoid valve (14) when the level reaches a certain value.
) is preferable.

Next, the functions of the apparatus according to the present invention will be explained. In this invention, the separated water accumulated in the separator (5) is appropriately discharged, and the concentration of the separated water is detected by the concentration detection sensor (10), and the output signal of the sensor is discriminated. Control is performed to adjust the amount of water supplied according to the degree of concentration. Specifically, when the degree of concentration of canned water becomes large, the amount of water supplied per unit time is increased to dilute the canned water (reducing the degree of concentration), and excess water is removed through a separator (5
) and discharged to the outside by a discharge means (14), and thereafter, when the concentration of canned water decreases, the amount of water supplied is reduced. In this way, the amount of separated water discharged is regulated in proportion to the amount of evaporation, and the degree of concentration of canned water is maintained at an appropriate level.

[0013] For variable control of the amount of water supplied, the amount of water supplied per unit time may be adjusted by comparing it with a preset concentration value and depending on whether the actual value is higher or lower than that value.
The amount of water supplied can also be varied in proportion to the degree of concentration. In this case, it is possible to set an upper limit value and a lower limit value of the water supply amount in consideration of the relationship between the performance of the separator and the risk of overheating the water tube. In addition, the concentrated water discharged from the separator is
Since it holds a considerable amount of heat, it is a good idea to recover the heat by exchanging heat with the water supply when discharging it.

[0014]

As described above, the present invention can control the amount of water supplied and the amount of separated water discharged to appropriate values, and can always maintain the degree of concentration of canned water at an appropriate level. Therefore, highly dry steam can be constantly and stably supplied, and problems such as blockage of water pipes and reduction in heat transfer coefficient due to overconcentration do not occur. Furthermore, the conventional problems of heat loss and water tube overheating due to excessive or insufficient discharge (excess or insufficient amount of water supplied) can be solved.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram showing a conventional embodiment.

[Explanation of symbols]

1 Water pipe 2 Burner 3 Water supply pump 4 Motor 5 Separator 6 Accumulator 10 Concentration detection sensor 11 Operation control unit 13 Control device

Claims (1)

[Claims] [Claim 1] One or more water pipes (1) and a burner (2)
In the configuration of a forced once-through boiler comprising a water supply pump (3) and a separator (5), a sensor (10) for detecting the concentration of separated water is attached to the separator,
A control device (13) that acts on the operation control unit (11) of the water supply pump by determining the output of the sensor and instructing the water supply amount to increase or decrease according to the concentration of separated water.
A control device for a forced once-through boiler, characterized by comprising: