MXPA99001539A - Device of a rotary regenerative heat exchanger - Google Patents

Abstract

The present invention relates to an arrangement in a regenerative, rotary heat exchanger for sensing and controlling the clearance between a flange (8) that projects radially outwards around the end surfaces of the rotor (1) and sector plates (3, 4) that move axially in relation to said end surfaces and that mutually separate the two heat exchanging media (5, 6). According to the invention, clearance sensing devices (7) are mounted on projections (12) which project out peripherally from the edges of the sector plates adjacent the rotor flange (8) such that the sensing devices are located in the flows of heat exchanging media.

Description

DEVICE OF AN EXCHANGED. OF ROTATING REGENERATIVE HEAT FIELD OF THE INVENTION The present invention relates to an arrangement in regenerative rotary heat exchangers, in particular with air preheaters, to detect and control the clearance between a flange projecting radially outwardly around the end surfaces of the rotor and plates of movable sector of the rotor in axial relation with the flange, the plates mutually separate the two heat exchange means.

BACKGROUND OF THE INVENTION Arrangements of this nature have been the subject of developments over time. The problem that must be solved is that the sensor and sensing accessories of the free space are particularly exposed to annoying environmental conditions, that is, to corrosive atmosphere and dirt, with considerable variations of pressure and temperature as the rotor rotates. This is because the rotor sectors pass through and out of the edges of the sector plates, the heat exchanger medium can flow P1115 / 99MX i alternately around the active sensors between the sector plates and the flanges of the rotor in high and low pressure alternately and exerts a disturbing influence on it. Despite efforts to compensate for disturbances, the effect of environmental conditions makes measurements unreliable. As a result of the above, the developments have been inclined towards more sophisticated solutions, such as slip-on shims that include advance feeding arrangements to compensate for wear and air cushion arrangements.

SUMMARY OF THE INVENTION The objective of the present invention is to provide a simple and reliable sensor or detector arrangement, in which environmental conditions do not have a significant effect. ! The objective is achieved with an arrangement having the features described in appended claim 1. The two preferred, separate embodiments are described in claims 2 and 3. As a result of placing detectors or sensors connected to the sector plates, outside the regions of said plates, that is, in the passages for the means of I exchange of heat, the conditions P1115 / 99 X to which the sensors are attached will be stable under normal operating conditions. As will be evident from claims 2 and 3, in a simple manner, the operationally reliable sensors or detectors are based on a through flood with compressed air for cleaning and cooling, the above can be used without subjecting the sensors to worse disturbances than those that can be compensated in an appropriate way. For the invention to be better understood and its characteristics to become more apparent, the invention will now be described in greater detail with reference to an exemplary embodiment of an array of inventive sensors and with reference to the accompanying schematic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES Figure 1 illustrates an air preheater seen from above; and Figure 2 illustrates, in side view, the operations of detection and control of the free space between the flange of the rotor and the sector plate.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates an air preheater P1115 / 99MX regenerative typically rotary, intended for the preheating of combustion air with the help of exhaust gases. The preheater includes a stationary housing 1 in which is mounted a rotating rotor having a regenerative mass and rotating at a speed of approximately one (1) r.p.m. The two sector plates 3, 4 are mounted for axial movement relative to the rotor and are disposed near the end surface of the rotor, both of which are above and below the rotor. The plates 34 of the sector separate a side 5 of gas from the side 6 of air, whereby, in spite of the fact that gas and air are able to enter below the edges of the plates of the respective sectors due to the rotation of the rotor, there is no need for direct leakage from one side to the other provided that the clearance between the plates 3, 4 of the sector and the ends of the rotor, can be kept reduced, despite the fact that the ends of the rotor they are never completely flat since they are subject to marked deviations from the flat shape, as a result of thermal deformations. The outer ends of the sector plates are each guided by two sensors 7. The sensors act together with the flange 8 extending circumferentially around the rotor, at the upper and lower end thereof, respectively, P1115 / 99MX as shown in Figure 2 for the upper part of the air preheater, seen in the direction of the arrow P in Figure 1, and with the adjustment means 10 connected to the sensor and which are fixedly mounted in the the housing 1 and articulated by means of hinges to the sector plates 3, 4 by means of their respective adjustment rods 11. The sensors 7 are mounted on the peripheral projections 12 that extend outward from a point radially farther from each of the side edges of each sector plate 3, 4 and, in a manner opposite to the flange 8 of the rotor that tends Adjacently. The rotor 2 is divided into sectors by walls 13 which extend radially, the vertical edges are marked in Figure 2. As the walls 13 pass the edge designated as K of the sector plate 4, from right to left in the drawing, the gas side 5 can suddenly communicate with sector 14, which results in abrupt changes in pressure and temperature until the sector designated with the number 15 takes the first position mentioned, that is, precisely in the position in which the free space sensors are usually placed. Corresponding perturbations occur at the other side edge (not shown in Figure 2) of the sector plate 4, where the air side 6 is located. Because they are mounted on the P1115 / 99MX projections 12, the sensors 7 will be located completely within the sides of the respective gas and air where the conditions of pressure and temperature are stable under normal operating conditions. Disturbances can occur only at the beginning or end of the work operation or eventually during marked load changes, where system monitoring may be necessary unless compensatory measures are taken. This allows the use of sensors driven with compressed air that are especially desirable in this particular context, whereupon the compressed air cools the sensors and, at the same time, cleans by blowing that region of the heat exchanger where the sensors are located . The free space can be detected or perceived by means of a jet of compressed air directed towards the flange 8, the magnitude of the free space is reflected in the pressure changes on the pressure side. Alternatively, piping operated with compressed air that is tuned to a specific resonance frequency can be used. Any change in the distance between the pipe hole and the flange 8 will result in a corresponding change in the resonance frequency of the pipe.

P111S / 99 X

Claims (3)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as property.
1. CLAIMS: 1. An arrangement in a regenerative rotary heat exchanger, in particular an air preheater, to detect and control the clearance between the flange projecting radially outwardly around the end surfaces of the rotor and the sector plates. movable which are in axial relationship with the flange, the plates mutually separate the two heat exchange means, characterized in that the sector plates are each provided with at least one projection projecting outwards from the periphery from an edge of the sector plates opposite to the rotor flange and in which the free space sensor accessory is mounted. An arrangement according to claim 1, characterized in that the free space sensor accessory includes means for directing a jet of compressed air to and above the flange of the adjacent rotor, whereby the pressure variations in the compressed air supplied operate to control the adjustment means, to adjust the placement of the sector plate.
2. P1115 / 99MX
3. 3. An arrangement according to claim 1, characterized in that the sensing accessory of the free space includes a pipe operated with compressed air, which is tuned to a specific resonance frequency and has an opening located adjacent to the flange of the rotor, so that the changes in free space can be represented by changes in the frequency of resonance of the pipe, the changes work to control a means of adjustment of plate 10 sector. • P1115 / 99MX