JPH01239312A - Control device for air pre-heater - Google Patents

Abstract

PURPOSE:To improve the heat exchange efficiency of an air pre-heater, by providing a rotor's upper position detector at a portion remote from a seal plate in the reverse direction of the rotor's revolution, and measuring distortions on the upper portion of the rotor in advance so as to maintain the sealing clearance to minimum. CONSTITUTION:A rotor's upper position detector 8 is mounted at a portion remote from a seal plate 1 in reverse direction of rotor's rotation, and measures a distance between the upper position of the rotor and the upper limit position of the seal plate to input it to a control device 7. A period of time required for the upper position of a control rotor to move a distance from its upper limit to its lower limit, and the initial value of the seal plate 1 are input to calculate an optimum position of the seal plate 1. The optimum position is defined as a position satisfying both conditions that the upper position of the rotor in continuous rotation is close enough to the back surface of the seal plate without coming into contact with the seal plate, and the upper position of the rotor in moving is close enough to the seal plate without coming into contact with the right lower edge of the seal plate while the seal plate is in ascending operating to correct its position. When the conditions are not satisfied, the seal plate is moved upward or downward by operating a motor 4, and the control is continuously carried out until the rotor stops.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Application in Industry-1-) The present invention relates to a control device for controlling the seal gap of a rotary air preheater in a thermal power plant.

(Prior Art) A general rotary air preheater is provided with a seal gap control device to prevent air or boiler exhaust gas from leaking from the gap between the rotor top and the seal plate.

An example of a conventional seal gap control device is shown in FIG.

1 is a seal plate to prevent air side and exhaust gas leakage, 2 is a seal support that lifts the seal plate upward, 3 is a gear box that changes rotational movement to vertical movement, and 4 is a seal plate that lowers the seal plate. The target motor, 5 is a rotor that exchanges heat between air and exhaust gas while rotating, 6 is a seal gap adjuster that fixes the seal gap between the seal plate and the upper part of the rotor, and 7 is a control device that controls the seal gap. It is.

As shown in FIG. 4, the seal plate 1 is supported from above to the outside by a seal support 2, and is configured to move downward as the seal support 2 moves up and down.

The rotational torque of the motor 4 is converted into vertical motion torque by the gearbox 3, and the seal support 2 is caused to move vertically by the same torque. Furthermore, the gearbox 3 and motor 4 are fixed externally so that they are always in constant positions. Is the gap between the seal plate 1-1 and the upper part of the rotor 5 the gap between the seal attached to the outer end of the seal plate? 1
The seal gap is converted into an electric signal by the regulator 6, and the seal plate 1 is adjusted according to the seal gap control flow shown in FIG.
By calculating the appropriate position of the motor 4 and controlling the motor 4, the lower position of the seal plate is controlled, and the seal gap is controlled.

FIG. 5 is a control flow diagram in the control device 7, and FIG. 6 is a graph diagram showing the relationship between the deflection of the upper part of the rotor, the seal plate position, and the seal gap.

A conventional control method will be explained based on FIGS. 4, 5, and 6. It is assumed that seal play 1- is at the upper limit when control is started.

In the flowchart of FIG. 5, numerals 10 to 12 indicate control logic for controlling the seal plate, and the control logic 10 determines the seal gap ΔI-1 for one rotation of the rotor 411.

Next, according to the control logic 11, the minimum value of the seal gap is 11H.
Calculate the engineering N. Next, according to the control logic 12, the motor 4 in FIG.
Outputs the drive signal to. At this time, the seal plate is moved from the seal plate initial position B to the proper position -C in FIG. PH to moving distance is ΔPtl = l1
1. IrNits.

Is this the same time again? The time Δt required for vJ is as follows, where the maximum moving distance of the seal plate is IIMx, and the time required for the same movement is TMX.

Also, moving Δ in time to the rotation angle of the rotor, r is
Let rr be the time required for the rotor to rotate once.

In other words, after the seal plate is moved to the proper position by the control rotor 12 in FIG. 5, according to logic 10, it takes Δ time to start reading the seal gap for one rotation of the rotor, and the value of the rotor rotation angle O° is Δr° from the previous value of Oo
It will be a divided place.

(9! Problem to be solved by Akira) However, although the system with the above configuration controls the seal gap by moving the seal plate 1 up and down,
Always the upper part of the rotor 5 where the distortion is high, II in Figure 6
Since there is a seal plate at the position of MTN-IIs,
Seal leakage occurs by the area of the valley in the Δ section. This reduces heat exchange efficiency.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a rotor upper part 41 fixedly installed at a distance from a vertically movable seal plate in a direction opposite to the rotational direction of the rotor. In play 1, not only the gap between the top and bottom of the rotor, but also the gap between the top and bottom of the rotor changes every moment,
I'll also look at the horizontal relationship with the top of the moving rotor.
By knowing the distortion in the upper part of the rotor in advance, the position of the seal plate can be made to follow the distortion in the gap for a certain period of time without contacting the upper part of the rotor, and the seal gap is always kept at the minimum.

(Function) By minimizing the seal gap, it greatly contributes to improving the heat exchange efficiency of the rotary air preheater.

(Example) FIG. 1 shows an example of the present invention. 1~ in Figure 1
7 provides the same function as explained in the section of the prior art, so its explanation will be omitted here.

A rotor upper di4 measuring device 8 is provided in place of the seal gap measuring device shown in FIG. The rotor heel measuring device 8 is mounted in a direction opposite to the rotational direction of the rotor from the seal plate 1, and is fixed so as to always measure the upper position of the rotor from the initial position of the seal plate.

Next, the control method will be explained based on the control flow diagram in FIG. 2 and the graph diagram in FIG. 3 showing the results of setting the rotor upper part 41.

When starting control, place the seal plate at the upper limit position. The control logic 10 determines all the time required to shift the rotor upper position from the upper limit position to the lower limit position. An example of the measurement results is shown in 3rd M.

The control logic 13 calculates lj & proper position of the seal plate. What is the optimal position here?

O) The position where the top of the rotor, which is constantly rotating, is close enough to the bottom of the seal plate to avoid contact ■ Even while the seal plate is being raised to correct its position, the position of the top of the rotor, which is constantly rotating, and the seal change constantly. Any position definition that is close enough that the lower right end of the plate does not touch is a satisfied position.

When neither of the conditions (1) and (2) are satisfied, the seal plate is moved up and down by control logic j2.

The control logic 15 performs a subsequent measurement of Δ, and the logic 13 performs a subsequent optimal calculation of Δ. Thereafter, control will continue until the rotor stops.

Here, an example of a method for calculating the optimal position of the seal plate will be described below based on FIG.

The vertical axis in FIG. 3 indicates the distance from the upper limit position of the seal plate to the top of the rotor, and the distance from the lower limit position of the seal plate.

The horizontal axis represents the passage of time and the 8#I distance above the rotor, but from now on, all distances will be converted into time for explanation.

The conversion formula is shown below.

First, the method for calculating the position in (1) above will be described.

The position where the top of the rotor, which is constantly rotating, is close enough that the bottom surface of the seal plate does not come into contact with the bottom surface of the seal plate is the position where the bottom of seal plate 1~, which has a width of PLT, is from the highest point between the top parts of the rotor a and b located directly below the same part. also means that it is located above the minimum allowable seal plate gap of 115 minutes.

In other words, the position +1A at this time is as follows.

+1A = HB-IIs・・・・・・・・・
... Equation (1) (IIB: highest part of the upper part of the rotor between a and b) Next, an example of the method of calculating the position of the above-mentioned (■) will be described. In order to correct the position of the seal plate, the position of the moving rotor changes every moment while the lifting operation is being performed, and the position where the lower right end of the seal plate does not come into contact with the lower right end of the seal plate means that the current seal is located at the lower right end of the plate. When moving to the plate upper limit position d, the line segment dI, which is a line segment located at a position lower than locus c and d by a JIS amount, can be said to be the seal plate position such that it does not contact the second part of the rotor.

In other words, the constant value of 81+1 at the top of the rotor between line segment 61 is o
If the vertical position of the y line segment c', d'''- is tlx, then d'
, d', it is sufficient if the following formula (2) is satisfied.

11x≦oy ・・・・・・・・・ Formula■
Here, the optimum position of the seal plate is a position that satisfies equation (1) and equation (2).

〔Effect of the invention〕

According to the present invention, the rotor 2 part, which is constantly moving during the rotor travel time Δt, can be brought close to the bottom surface of the seal plate to the extent that they do not come into contact with each other, and the rotor The seal gap can be kept to a minimum by calculating the position where the bottom right end of the seal plate does not come into contact with the lower right end of the seal plate.

This makes it possible to obtain an automatic seal plate tracking device for a rotary air preheater that minimizes the amount of leakage and greatly contributes to improving the heat exchange efficiency of the rotary air preheater.

[Brief explanation of the drawing]

Fig. 1 is an eyelid diagram of a seal play 1-automatic tracking device showing an embodiment of the present invention, Fig. 2 is a control flow diagram for controlling the control shown in Fig. 1, and Fig. 3 is a diagram of the rotor shown in Fig. 1. A graph showing all undefined parts of the two-part h+II regulator, Fig. 4 is a bird's-eye view of the seal plate control device according to the prior art, Fig. 5 is a control flow diagram for performing the control shown in Fig. 4, and Fig. 6 is the diagram shown in Fig. 4. It is a graph diagram showing the measurement results of the seal gap 411 constant device. 1...Seal play 1~2...Seal support 3...Gear box 4...Motor 5...Rotor 6...Seal VX measuring device 7...Control device 8...Rotor top Measuring instruments 10.11, 1.2, 13, 14.15...Control logic agent Patent attorney Noriyuki Chika Kendai Daikomaru 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A rotary type air preheater seal gap control device that detects the ever-changing distortion of the top of the rotor in advance to control the seal plate and the top of the rotor so that they always maintain a constant gap without contacting each other. Air preheater control device.