JPS599411A - Monitor device for performance of feed pump in boiler system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a performance monitoring device for monitoring performance deterioration of a water pump in a boiler system, and in particular, measures a water pump flow rate corresponding to steam pressure in a water pipe of a boiler system. The present invention relates to a new water pump performance monitoring device that determines the performance of a water pump by comparing it with a preset reference flow rate.

Generally, a boiler system has a water supply control means that keeps the water level in the boiler within a certain range regardless of the steam load (amount of evaporation), and responds to a control signal from the control means. It is equipped with a water supply pump to supply canned water intermittently. Now, if the performance of the water supply pump deteriorates and the water supply capacity becomes insufficient, and it becomes impossible to forcefully pump canned water against the steam pressure in the water pipes, it is necessary to maintain the water level in the water pipes within a certain range. This makes it impossible to optimize boiler operation, and there is a risk that water pipes may burn out. therefore,
Monitoring the performance of the water pump and confirming that there is no deterioration in performance is essential for boiler operation management.

In order to test the performance of a water supply pump, the performance can be determined by stopping the operation of the boiler system and measuring the discharge amount of the pump at atmospheric pressure. In this way, if the pump is in a stopped state, there is no need to measure the steam pressure, which affects the load on the pump, and there is the practical benefit of being able to conduct the test very easily.

However, the above test only measures the discharge amount under a pressure equivalent to the water pressure of canned water remaining in the water pipe, so it determines the performance of the pump under the added steam pressure during boiler operation. I couldn't. Furthermore, in a region where the load on the pump is small, even if the pump has deteriorated, there is no obvious difference in its performance, making it difficult to accurately judge the performance.

The purpose of the present invention is to provide a flow rate of feed water discharged from a feed water pump against a large load due to steam pressure during operation of a boiler system, in view of problems such as measurement accuracy related to pump performance judgment based on the above-mentioned conventional technology. By measuring this, pump performance can be accurately and automatically determined without stopping boiler system operation, and when performance deterioration is determined, smart,
The purpose of the present invention is to provide a water pump performance monitoring device for a stirred boiler system that is capable of displaying information.

The structure of the present invention in accordance with the above object includes: a steam pressure measurement section having a pressure sensor that outputs a steam pressure signal corresponding to the steam pressure in the water pipe; and a heating device that heats the water pipe in response to the steam pressure signal. a combustion control unit that starts or stops the water pump; a water level detection unit that detects the can water level in the water pipe and outputs a water level signal; and a water supply control unit that starts or stops the water pump in response to the water level signal. In the boiler system, the steam pressure in the water pipe is measured by a steam pressure measurement section, a reference flow rate search section is searched based on the steam pressure, and the steam pressure and reference flow rate stored in the search section are determined. A reference flow rate corresponding to the actual steam pressure is read out from a table showing the relationship with the discharge flow rate of a normal water supply pump, and the performance is determined based on the magnitude relationship between this and the actual discharge flow rate measured by the flow rate measurement unit. By comparing the two parts, we can take advantage of the fact that at the operating point on the flow-to-head curve of a water supply pump that corresponds to a state with a large load due to steam pressure, there is a very large difference in water head due to pump performance deterioration. The main purpose of this method is to make it possible to clearly determine performance deterioration.

Now, prior to the detailed description of the present invention that follows, the configuration and operation of a typical small boiler system to which the configuration of the present invention can be attached will be explained as follows.

FIG. 1(A) is a block explanatory diagram showing the configuration of such a boiler system, and a cross section of the boiler 1 is shown.

FIG. 1(B) is a sectional view taken along the line AA in FIG. 11(A).

In the figure, inside the boiler 1, a large number of water pipes 1b are installed along the inner circumferential surface of the wall 1a, and the water pipes 1b are made of a hollow cylindrical body, and the lower end thereof is an annular lower header 1c (ice chamber).
, and its upper end is also an annular upper header 1d.
(steam room), and canned water is stored in the lower part of the lower header 1C and the water pipe 1b.

A combustion chamber 1e is located in the center of the boiler 1 surrounded by water pipes 1b.
formed from. At the top of the boiler 1, a wind passage 1h is provided which communicates with a blower 1g driven by an electric motor 1f, and within the wind passage 1h are nozzle rods 1i, ! : The pole rod 1j is vertically installed.

The lower end of the combustion chamber 1e communicates with the flue 1k through the hollow portions of a large number of water pipes 1b. From the upper header 1d, the communication pipe 1
1 extends outside the wall 1a and communicates with the lower header 1C.

A water level gauge 1 m and a water level detection unit 2 are installed in the middle of the communication pipe 11 to visually display the water level of the canned water. A water supply control section 3 is connected to the water level detection section 2, and its output terminal is connected to an electric motor 4aK that drives a water supply pump 4. An inlet pipe of the water supply pump 4 communicates with a water source (not shown), and a discharge pipe thereof communicates with the lower header 1c.

Further, a vapor pressure measuring section 5 is connected to the upper part of the communication pipe 11, and its output terminal is connected to a combustion control section 6. Control cables 6'a to 6'c extend from the combustion control section 6 and are connected to the electric motor 1f, electrode rod 1J1, and fuel pump 6'd, respectively. An inlet pipe of the fuel pump 6'd communicates with a fuel tank (not shown), and a discharge pipe thereof communicates with the nozzle rod 11. A blow pipe 1n extends from the lower header 1C and communicates with a drainage channel (not shown) via a blow cock 1p, and a steam pipe 1q extends from the upper header 1d to meet a desired steam load (not shown). communicate.

In the above boiler yarn configuration, when generating steam, the blower 1g is driven by the electric motor 1f to forcefully feed air into the air passage 1h, and a voltage is applied to the electrode rod 1jK to inject it from the tip of the nozzle rod 11. The fuel is ignited and combusted in the combustion chamber 1e. High-temperature combustion gas generated by such combustion enters the hollow part of the water pipe 1b from the lower end of the combustion chamber 1e, passes through it, reaches the flue 1k, and is exhausted.

During this time, heat exchange is carried out to heat the canned water in the water pipe 1b and turn it into steam, which is collected and accumulated in the upper header 1d and supplied to the steam load through the steam pipe 1q.

Regarding combustion control, the steam pressure in the upper header 1d is extracted through the communication pipe 11 and supplied to the steam pressure measuring section 5, where the steam pressure in the upper header 1d is set in advance. When it is detected that the lower limit vapor pressure has been reached, a lower limit vapor pressure signal is sent to the combustion control section 6, and similarly, when it is detected that the souvenir vapor pressure has been reached, an upper limit vapor pressure signal is sent to the combustion control section 6.

The combustion control unit 6 continues to consume steam and the upper g valley 1d
When the vapor pressure in the tank drops and a lower limit vapor pressure signal is received from the vapor pressure measuring section 5, the electric motor 1f is started together through the control signal line 6'a, and the blower 1g is used to purge air from the j quotient and the road 1h. Then, a high voltage is applied to the electrode rod 1j through the signal line 6'b, and the control signal line 6'
Start the fuel pump 6'd through the nozzle rod 1
The fuel injected from 1 is ignited to start combustion, and further,
As the steam continues to be generated, the steam pressure increases, and the steam pressure measuring section 5
When receiving the upper limit vapor pressure signal from the control signal line 6'
By stopping the fuel pump 6'd through c and cutting off the fuel supply, the combustion is stopped, and after the combustion gas is discharged, the electric motor 1f is stopped through the control signal i6'a.
and cut off the air from the blower 1g.

By controlling the combustion on and off, the steam pressure in the upper header 1d can be maintained at a pressure value between the two positive pressure values preset as the upper and lower steam pressure limits.

In addition, in a simple device, electric motor 1f1 fuel pump ii'
The start/stop control of d and the application of high voltage to the electrode rod 1j may be performed simultaneously.

Furthermore, regarding the water supply system, the air-water interface in the communication pipe 11,
That is, when the change in the can water level in the water pipe 1b is transmitted to the water (9) level detection pressure 1 part 2, and the water level detection part 2 detects that the can water level has reached the preset lower limit water level,
Similarly, when it is detected that the lower limit water level signal has reached the upper limit water level, the upper limit water level signal is sent to the water supply control section 3.

When the can water level in the water pipe drops due to steam consumption and a lower limit water level signal is received from the water level detector 2, the water supply control unit 3 starts the electric motor 4a and uses the water supply pump 4 to lower the lower pipe header 1c. water supply to the water pipe 1b is started, water supply continues and the can water level rises, and when an upper limit water level signal is received from the water level detection part 2, the lIt motor 4a is stopped to cut off the water supply to the water pipe 1b.

Thus, by intermittent water supply control, the water level of the canned water in the water pipe 1b can be maintained at a water level between the upper and lower limit water levels preset.

The intermittent control of water supply and the intermittent control of combustion are performed separately and independently from each other.

When blowing the shredded canned water, by opening the blow cock 1p, a part or all of the canned water in the lower header 1C and the water pipe 1b can be blown out through the drain pipe 1n. It is.

Gao, blower 1g1 airway 1h1 nozzle rod 111 electrode rod 1
The burner made of Any device is fine.

Similarly, the combustion control section 6 may also be a heating control section that turns on and off the heating device.

Next, the construction and operation of the embodiment of the present invention will be explained based on FIGS. 2 and 3 as follows.

FIGS. 2 and 2 are block diagrams showing an embodiment of the present invention. In the figures, components denoted by the same reference numerals as those in FIG. 1 correspond to those in FIG. 1, respectively. There is.

The flow rate measurement unit 1 is connected to the discharge side of the water supply pump 4 and the lower pipe header 1.
It is inserted in the song "C" and consists of a flowmeter 7a and a potentiometer 7c having a movable slider that moves in conjunction with the float 1b of the flowmeter. Note that the Taber pipe flow meter 7a is not limited to these, and if necessary, it is sufficient to generate a flow rate signal corresponding to the flow rate of canned water sent to the water pipe 1b by the water supply pump 4. Of course, it is possible to replace the flowmeter with a flowmeter other than the flowmeter. Furthermore, a system in which the flow rate is converted based on the time from when the water level detection section 2 outputs the lower limit water level signal to when it outputs the upper limit water level signal during control is also referred to in this specification. Included in measurement means.

The reference flow rate search unit 8 includes an analog-digital converter 8a.
a memory 8b following the memory 8b; a digital-to-analog converter 8c following the memory 8b (12) and the converter 8a;
, 8c and a clock oscillator 8 connected to the memory 8b.
d, the input terminal of the analog-digital converter 8a is connected to one output terminal of the vapor pressure measuring section 5, and the output terminal of the digital-analog converter 8c is connected to the performance determining section 9 through a potentiometer 8e. Comparator 9a of
connected to one input terminal of the The input terminal of the comparator 9a is connected to the potentiometer 7 of the flow rate measuring section T.
It is connected to the slider terminal c. The output terminal of the comparator 9a is connected to the input terminal of the alarm display section 100.

FIG. 3 is a graph showing the performance of the water supply pump when the number of revolutions of the pump is kept constant, in which flow-II (Q) is shown on the horizontal axis and water head (H) is shown on the vertical axis. Solid line a in Figure 3
represents an example of a normal pump characteristic curve, and when the pump performance deteriorates, the flow rate (H) corresponding to the water head (H)
As Q) becomes smaller, the characteristic curve becomes as shown by the broken line. The water head (H) varies depending on the operating condition of the boiler. For example, when starting new water supply after the canned water has been completely blown (13), the water head (H)
H) is equal to atmospheric pressure. Further, if the structure of the boiler system is such that canned water is supplied from the bottom of the water pipe, the pressure based on the canned water level will be the pressure value added to atmospheric pressure.

Further, when the boiler system is in operation and the steam pressure in the upper header 1d is rising, in addition to the above-mentioned atmospheric pressure and water pressure, a large steam pressure is added as a load to the pump. Normally, the steam pressure during boiler operation is much higher than the atmospheric pressure or the water pressure of canned water, so if the steam pressure during operation is (P), then the water pressure (water head) can be represented by steam pressure (P). No problem.

Therefore, on the vertical axis of FIG. 3, Px represents the steam pressure during boiler operation, and P, PL represent the upper and lower limits of steam pressure within the upper header 1d during intermittent control of combustion. .

As is clear from the characteristic diagram in Figure 3, the characteristic curve ia of a normal pump and the characteristic curve of a deteriorated pump are different from each other.
) is small, that is, when the boiler is not in operation, there is almost no difference in the apparent characteristics, and it is generally difficult to judge whether the boiler is good or bad.

Another solid line C in FIG. 3 is a reference flow rate line predetermined as a standard for determining whether the performance of the pump is good or bad. Therefore, when the vapor pressure during operation is Pa, if the flow rate of the pump is equal to or lower than QB, it can be determined that the performance of the pump has deteriorated.

Next, with reference to FIGS. 2 and 3, the flow rate measurement unit 1,
The operations of the reference flow rate search section 8, performance determination section 9, and alarm display section 10 will be explained as follows.

First, when the vapor pressure signal Sl from the vapor pressure measuring section 5 is supplied to the input terminal of the analog-to-digital converter 8a of the reference flow rate searching section 8, the analog-to-digital converter 8
In response to the clock pulse S2 from the clock oscillator 8d, the vapor pressure signal Sl, which is an analog quantity, is sampled, quantized, and digitally encoded. Then, the analog-digital converter 8a outputs a digital sign (
15) The steam pressure signal S/ of No. 1 is stored in memory 8 as an address signal.
is supplied to the address terminal of b. Then, the memory 8b
At this time, receives the clock pulse S2 from the clock oscillator 8d at the control terminal, synchronizes with the sampling of the analog-digital converter 8a, enters the enable mode, and changes the pre-stored vapor pressure Px to reference flow rate Q, A reference flow rate corresponding to the steam pressure represented by the steam pressure signal S/l is determined according to a table representing the relationship, and a reference flow rate signal SI3 representing this in a digital code is output.

Such a search process is carried out from the vapor pressure P on the vertical axis along the reference flow line C to the corresponding flow rate Q on the horizontal axis in FIG.
This corresponds to the process of determining s, and such a relationship can be easily determined by actual measurement for each boiler system. The reference flow signal S'3 outputted by the memory 8b is then supplied to a digital-to-analog converter 8c, which also loads the signal S'3 in response to the clock pulse S2 and converts it into an analog to analog converter 8c. The reference flow rate signal S3 is converted into a reference flow rate signal S3 and supplied to the potentiometer 8e.

(16) Next, the float 7b of the flowmeter 7a installed in the flow rate measurement section 7
A flow rate signal S representing the discharge flow rate of the pump 4 is generated by a potentiometer re having a movable slider interlocked with the flow rate signal S.
4 and a potentiometer 8 included in the reference flow rate search unit 8
A reference flow rate signal s3 adjusted to an appropriate magnitude by e is supplied to both input terminals of a comparator 9a of the performance determining section 9.

Then, the comparator 9a compares the magnitude relationship of both signals s3.84, and when the flow rate signal S4 is smaller than the reference flow rate signal s3, it outputs a performance judgment signal S6 indicating the deterioration state of the water supply pump, and receives this. The alarm display section 10 visually displays that the performance of the water supply pump has deteriorated.

In addition, in the configuration of the above embodiment, when searching for the reference flow rate, both the vapor pressure P1 and the reference flow rate Q8 are treated as continuous quantities, but the invention is not limited to this. When the steam pressure PL is in the range between the boiler operating state and the steam pressure P is lower than the lower limit steam pressure Pt (including atmospheric pressure), that is, when the steam pressure P is lower than the lower limit steam pressure Pt (including atmospheric pressure),
The boiler operating state is divided into two states: the boiler non-operating state, and the boiler operating state has a reference flow tQ corresponding to the upper limit steam pressure PU and a lower limit steam pressure PU along the solid line C in Fig. 3. A configuration in which the actual flow rate of the feed water pump under boiler operating conditions is compared with a specific average reference flow rate also under boiler operating conditions by assigning an average value of reference H, t QsL corresponding to steam pressure PL. It is optional to do so.

In this way, the reference flow rate search section in Fig. 2≠
, 41) There is a practical benefit in that the configuration can be significantly simplified and an economical water pump performance monitoring device can be obtained.

As described above, the present invention provides a table representing the relationship between the actual flow rate of water supplied by the feed water pump, the steam pressure, and the corresponding reference flow rate in a boiler system in which the heating device and the feed water pump are independently and intermittently controlled. The system is configured to determine the performance of the water pump based on the magnitude relationship with the reference flow rate corresponding to the actual vapor pressure retrieved according to the
Without stopping the operation of the boiler system, it is possible to judge the performance of the feedwater pump under a large load due to steam pressure. Performance can be judged in the operating range where the characteristics change significantly.

Therefore, according to the present invention, it is possible to determine the performance deterioration of the water pump extremely accurately without being affected by variations in individual performance, and in turn, it is possible to more reliably prevent equipment burnout due to dry boiler heating. It has the excellent effect of preventing

[Brief explanation of the drawing]

FIG. 1(A) is a block diagram showing the configuration of a small boiler system to which the configuration of the present invention can be attached, and FIG. 1(B) is a sectional view taken along line AA of the boiler 1 in FIG. 1(A) . FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 3 is a graph showing the relationship between pump flow rate Q and water head H. 1...Boiler 2...Water level detection unit 3...Water supply control unit 4...Water supply pump 5...Steam pressure measurement unit 6...Combustion Control part I...Flow rate measurement part 7a...
Flow meter 8...Reference flow rate search section 9...Performance judgment section 10...Jurisdiction display section Patent applicant Ebara Corporation

Claims (1)

[Claims] In a boiler system having at least a water supply pump 4 that supplies canned water into the water pipe 1b where the internal steam pressure changes, the flow rate of canned water supplied into the water pipe 1b by the water supply pump 4 is controlled. A flow rate measuring means T that measures the steam pressure in the water pipe and outputs the measurement result as a flow rate signal S4, and a steam pressure measuring means 5 that measures the steam pressure in the water pipe and outputs the measurement result as a steam pressure signal Sl.
, a reference flow rate search means 8 that searches for a reference flow rate Q8 of canned water corresponding to the steam pressure based on the steam pressure signal S1, and outputs the search result as a reference flow rate signal S3;
4 and a performance determining means 9 for determining the performance of the water supply pump based on the magnitude relationship between the reference flow rate signal S3 and outputting the determination result as a performance determination signal S5 (1). Water pump performance monitoring device for boiler systems.