JPS6256784A - Seal gap regulating device for air heater - Google Patents

Abstract

PURPOSE:To obtain a seal gap regulating device for a rotary heat regenerating type air heater, high in heat resistance and in safety, by a method wherein heating temperature of a rod consisting of a material having a large thermal expansion coefficient is controlled to change the stroke of a driving machine for a system. CONSTITUTION:A thermal expansion rod 1 is attached to the fixing section of an air heater and hangs a sector plate (radial seal) 2 through a lever mechanism 5. A sensor 4 is arranged on the sector plate 2 and detects a relative gap between a rotor 7. Here, the detecting value of the sensor is compared with a set value, while an error signal is amplified by an amplifier 9 and is inputted into a variable output electric source 8. Heating or cooling (electric source OFF) of the thermal expansion rod 1 is controlled by a power source 8, and a feedback control is effected so that the gap between the plate 2 and the rotor 7 becomes constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is intended for use in a seal gap device for a rotary heat regenerative air heater, and has application in the technical field of reducing leakage between air flow and hot gas.

Prior Art Conventional examples are shown in FIGS. 5 to 10, and an overview of the overall configuration of the target product will be described.

FIG. 5 shows the configuration of the rotary heat regeneration type air heater.

As shown in the figure, the rotor 14 having a large number of heat storage elements 13 is rotating in the direction of the arrow, and cold air is supplied from the cold air inlet duct 15 in the direction perpendicular to the rotating surface, and the rotor 14 is rotating in the opposite direction. Hot gas flows from the hot gas component from the opposite direction to the cold air, perpendicular to the surface, and heats the heat storage element 13 while passing through the gas side.

The heated element 13 performs heat regeneration by heating the cold air while passing through the air side, and is cooled by itself. In this way, it is a heat exchange device that performs heat exchange using the heat storage element 13 as a medium.

FIG. 6 shows a typical structure of a rotary regenerative air heater.

Here, the sector plate 2 is a seal component that separates two heat exchange fluids, and the re-fluid is insulated by this seal. In the figure, 20 is a seal ring segment, 21 is an adjuster, 22 is a trunnion, and 23 is a rotor.

FIG. 7 shows the operating condition in which this air heater receives hot gas 24 and exchanges heat with the air flow. That is, the rotor 7 is thermally deformed because the upper side in the figure is the high temperature side 24 and the lower side is the low temperature side 27, and due to the warp of the rotor 7 as shown in the figure, a gap is generated in the sealing surface of the sector plate 2, and the fluid is not mutually connected. leakage occurs.

In order to compensate for this thermal deformation gap, an automatic gap compensation device of the type shown in FIG. 8 has been put into practical use. In the figure, 2 is a sector plate, 4 is a sensor, 7 is a rotor, 19 is a radial knob, 22 is a trunnion, 28 is a bearing,
29 indicates a starting device.

The amount of thermal deformation is detected by a gap sensor 4 placed on the sector plate 2, and if this gap increases, it is detected as an error with the setting and increases, and as a result, the sector plate drive actuator (an electric motor is used) ), the sector plate gap 3 is compensated for, and the gap is kept almost constant.

The control function of the above system is shown in FIG. In the figure,
4 is a sensor, 7 is a rotor, 30 is a proximity switch, 31 is a cam, 32 is a displacement, 33
is the output, 34 is the in-play), 35 is the controller, 36 is the jack, 37 is the gear motor, 38 is the drive system, 39 is the strain gauge, and 40 is the sector (hot side).

FIG. 10 shows the configuration of a conventional seal gap adjustment device. In the figure, 2 is a sector plate, 3 is a sector plate control gap, 4 is a sensor, 7 is a rotor, 10 is a gap setting, 50 is an electric motor, 51 is a gear mechanism, 52 is a frame, 5
3 indicates a screw mechanism, and 54 indicates a control device.

As shown in Figures 8 and 9, conventional gap compensation systems use electric motors, air motors, hydraulics, etc. to drive the sector plate 2, but these have the following drawbacks. ing.

a) Heat: It is difficult to use in a relatively high-temperature atmosphere (due to the heat resistance of the equipment), and because the drive unit is located far from the hot atmosphere, a complicated link mechanism is required, making it expensive.

b) Trouble detection and backup mechanisms are complicated to prevent system malfunctions. The reason for this is (a), since the electric motor is a rotating type, if the control system malfunctions, it can easily run out of control and become dangerous. (B).

If something breaks, it doesn't necessarily mean you'll be on the safe side. (c).

Due to the movement (parts, links, screws, electric motors, etc.), the probability of failure is high.

Problems to be Solved by the Invention A thermal expansion rod equipped with an electric heating part is used as the driving machine of the system, which has good heat resistance and self-restoring property (when the electric heating part is damaged, it contracts and moves to the safe side). It's about having it.

Means for Solving the Problems The present invention takes the following measures in order to solve the above-mentioned problems. That is, it has a heating function using electric heat, changes the temperature by changing the heating energy, and is used to stroke a radial knob or drive an axial seal, or has an air passage for rapid cooling. , an air heater seal gap adjustment device consisting of a thermal expansion rod having a structure that injects cooling air when necessary.

Effect Utilizing thermal expansion in Figures 1a, lb, and lc 1. Additionally, the drive rod 1 is shown. In the figure, 8a is a power supply, 8b is an AC power supply, 11 is a resistance wire heater, 12 is a thermal expansion material, 14
indicates a coil.

A. Regarding the operating principle, a) As much as possible, use a thermal expansion material 12 with a low coefficient of thermal expansion.

1) A resistance wire heater 11 (Fig. 1a) having one of the following heating means on the rod 1, that is, one heating resistor.
°, induction heating by applying an alternating current voltage to the outer circumferential coil 14 (Fig. ib), self-heating by passing a large current through the rod itself to generate heat (Fig. 1c), and the amount of heating power for these can be controlled.

c) The driving stroke is controlled by the heating temperature of the rod 1, and the required stroke is obtained by changing the temperature.

B. Regarding cooling, a) In the case of electric heating only, by cutting off the heating or reducing the heating power, it is possible to cool by heat radiation such as solid heat conduction, convection, radiation, etc., and stroke in the direction of contraction.

(1) Combination with forced cooling When rapid cooling, that is, contraction is required, cooling air can be injected for rapid cooling (this can be used in emergencies, etc.).

Regarding application to C9 automatic gap control, it can be applied as the actuator shown in Figure 9, and can be used as a closed loop to detect the gap, heat or cool the thermal expansion rod, and stroke it so as to maintain a constant gap. can.

Embodiment Next, an embodiment of the present invention will be described in detail, with an example of mounting shown in FIG.

The thermal expansion rod 1 is attached to the air heater fixing part, and is connected to the sector plate (radial seal) via the lever mechanism 5.
2 is suspended. These gaps are adjusted by the initial adjustment screw mechanism 6 in a cold state. In this case, when the thermal expansion rod 1 is set in the heating direction, the sector plate control gap 3 is installed in a decreasing direction.

The sensor 4 is arranged on the sector plate 2 and detects the relative gap with the rotor 7. Here, the sensor detection value is compared with the set position, and the error signal is amplified by the amplifier 9 and input to the variable output power supply 8.

Here, the variable output power supply can have the following configuration.

b) On-off control power supply port) Variable voltage power supply c) Pulse width modulation switching power supply This power supply controls heating or cooling (power off), and performs feedback control to maintain a constant gap.

Next, we will discuss the cooling function.

For cooling, in addition to the above-mentioned natural cooling, forced cooling as shown can be used in combination. These solenoid valves are opened and closed according to cooling signals from the control device as necessary. Add this configuration to the third
As shown in the figure. In the figure, 14a is a cooling air passage, 14b is a cooling air outlet, and 23 is a pneumatic pressure.

Next, application to axial seals will be described.

To prevent bypass flow in the same axial direction as the fluid flow, an axial paddle 41 can be placed around the outer circumference of the rotor. This arrangement is shown in Figure 4, where 2
19 indicates a sector plate, 19 indicates a radial seal, and 41 indicates an axial seal.

The configuration described here can be applied as it is as a clearance control system for an axial seal.

Effects of the Invention When the seal gap adjusting device according to the present invention is adopted, the following effects can be obtained.

a) Since the actuator is inherently heat resistant, it can be placed near the sector plate where thermal conditions are poor;
The drive mechanism is simplified. This makes the price cheaper and
Reliability is improved.

b) Even if the heating system fails, the rod side is cooled and has an inherently safe function of contracting in a safe direction, simplifying the security and backup mechanism, making it a low-cost, highly reliable system. can be realized.

C) The thermal expansion rod itself is not a dynamic mechanism and is highly reliable.

[Brief explanation of the drawing]

Figures 1 to 4 relate to the present invention, Figure 1a is a sectional view of a thermal expansion rod using a resistance wire heater, Figure ib is a side view of a thermal expansion rod using a coil, and Figure 1c is a thermal expansion rod. FIG. 2 is a system diagram showing the configuration of an example in which the thermal expansion rod of the present invention is applied; FIG. 3 is a cross-sectional view showing the configuration of the cooling function; FIG. 4 is a perspective view showing application to axial seals, and Figures 5 and below are conventional Shio!
], Fig. 5 is a perspective view showing the configuration of a rotary heat regeneration type air heater, Fig. 6 is an exploded perspective view showing a typical configuration of a rotary regeneration type air heater, and Fig. 7 is a perspective view showing the configuration of a rotary regeneration type air heater. Figure 8 is a perspective view showing the automatic gap compensation device, and Figure 9 is a side view showing the operating state in which the airflow is exchanged with heat. Figure 9 is a side view showing the operating state in which the air flow is heat exchanged. A system diagram of the control system, FIG. 10 is a system diagram showing a seal gap adjustment device. 1. Thermal expansion rod, 2. Sector plate, 3.
Sector plate control gap, 411 # sensor, 5.
- Lever mechanism, 6... Initial adjustment mechanism, 7... Heater, 8
・Variable output power supply, 9...amplifier, 10...gap setting,
11...Resistance wire heater, 12...Thermal expansion material, 13...Heat storage element, 14a...Cooling air passage, 14b...
- Cooling air outlet, 15... Cooling air inlet duct, 16
-Hot gas inlet duct, 17...Cold gas outlet duct, 1
8. Heated air ratio Rodak), 19 φ radial seal,
41...Figure 5 51 Figure 7 Figure 9

Claims (1)

[Claims] This is an actuator for driving a radial seal used to improve the sealing performance of a rotary heat regeneration type air heater, and has a heating function by electric heating, and changes the temperature by changing the heating energy, thereby increasing the temperature of the radial seal. An air heater seal gap adjustment device consisting of a thermal expansion rod that is used to stroke or drive an axial seal, or has a rapid cooling air passage and has a structure that injects cooling air when necessary.