DK2784386T3

DK2784386T3 - Device for load measurement or load adjustment

Info

Publication number: DK2784386T3
Application number: DK14020019.7T
Authority: DK
Inventors: Ralf Breidbach; Frank Miunske; Harald Schröder
Original assignee: Steinmueller Babcock Env Gmbh
Priority date: 2013-03-28
Filing date: 2014-02-26
Publication date: 2019-01-07
Also published as: EP2784386A1; EP2784386B1; DE102013005569A1; ES2701421T3

Description

The present invention is directed to an assembly for load measurement or load adjustment in a boiler element which is suspended from a framework beam of a boiler framework via at least one anchor, wherein the anchor comprises threads at least on its free end and passes through an anchor plate resting on the framework beam, and wherein an anchor nut, which directly or indirectly abuts on the anchor plate, is screwed onto the anchor.

In a boiler support known from DE 29 19 210 C3, the anchors are suspended via spring supports on a framework beam of the boiler framework, wherein the respective base plate of the spring supports abuts on the framework beam as an anchor plate, and wherein the anchor nut, which is not shown in the figure, abuts on the upper plate of the spring suspension.

Furthermore, boiler supports are known, where a double roller plate, which is penetrated by the anchor, rests on the anchor plate, and wherein a load distributor plate, which is penetrated by the anchor, rests on the double roller plate, wherein the anchor nut abuts on the load distributor plate.

It is desirable that all anchors of such supports receive the load which is specified in the design calculations. The anchor loads set upon assembly of the boiler may change during operation of the boiler, e.g. due to boiler fouling or constructional provisions (e.g. new linings) such that the anchor loads have to be adjusted again. A load assembly according to the pre-characterizing portion of claim 1 is known from WO 93/05338.

It is the object of the invention to provide an assembly for easy load measurement or load adjustment.

This object is achieved by an assembly for load measurement or load adjustment according to claim 1.

Given that the load cell is provided between the cage and the lifting device, the real existing anchor load can be measured directly in the assembly for easy load measurement or load adjustment according to the invention, and the anchor load can be compared to a pre-determined target value. This may be carried out e.g. during on-going operation.

Furthermore, the assembly according to the invention needs comparatively little space above the boiler ceiling and has a low weight for temporary assembly. Adverse side effects, such as anchor torsion and deformation of the boiler framework under the influence of the load adjustment, can be compensated by means of the assembly.

In one example, a double roller plate penetrated by the anchor abuts on the anchor plate, and a load distributor plate, penetrated by the anchor, abuts on the double roller plate, wherein the anchor nut abuts on the load distributor plate. In this way, bending moments on the anchor can be avoided, particularly at the beginning of the anchor threads. The double roller plate is preferably used for larger strain distances of the boiler and, accordingly, for larger inclinations of the anchor.

In case of a spring support, the anchor plate is the lower plate of a spring support, and the anchor nut abuts on the top plate of the spring support. The spring support can be formed as a spring packet of Belleville springs oriented in the same direction or can be formed as a spring column formed from Belleville springs oriented in an opposing manner.

The device for torsion free lifting preferably consists of an expansion nut having an inner bushing which has inner threads corresponding to the anchor threads, an outer bushing and a washer and a torque screwing device engaging with the outer bushing and being electrically operable or operable via pressurized fluid. Thus, the anchor can advantageously be lifted free of torsion and free of lateral loads in a particularly space saving manner.

The invention further relates to a method for load measurement or load adjustment using an assembly for load measurement or load adjustment, wherein the method comprises the following steps: lifting the anchor by rotating the expansion nut via a torque screwing device until the anchor nut is free of load, thus loading the load cell, untightening the anchor nut so as to avoid load on the anchor nut during the anchor load adjustment, determining the anchor load via the measured value determined by the load cell, comparing the determined anchor load to the target value according to the design, tightening or untightening the expansion nut by means of the torque screwing device so as to adjust the anchor load to the target value, and tightening the anchor nut.

The invention further relates to a method for load adjustment for a plurality of anchors by means of a plurality of assemblies according to the description above, wherein each assembly is associated with one anchor. In this method, the measured values of the plurality of assemblies are retrieved in pre-determined time intervals and are displayed for recognizing load variations. Preferably, all loads of the anchors hanging on (or supported from) the load cells can be observed. Furthermore, the load variations of the neighboring anchors can be directly observed together during load adjustment of a single anchor. Thus, it is possible to compare the current actual boiler loads of all anchors with the target values or a target graph, respectively, without the need to relocate some of the components of the measurement assembly from one anchor to another anchor.

Further preferred embodiments of the invention are defined in the dependent claims.

The invention shall be explained in the following with reference to the attached figures:

Fig. 1 shows an embodiment of the assembly according to the invention for an anchor which transfers its load via a spring support to the framework beam,

Fig. 2 shows an example of the expansion nut used in the embodiment of Fig. 1.

Fig. 3 shows an embodiment of the arrangement of Fig. 1 according to the invention for an anchor which transfers its load via a double roller plate to the framework beam, and

Fig. 4 shows the simultaneous use of a plurality of assemblies for load adjustment for a plurality of anchors.

Fig. 1 shows a framework beam of a boiler framework, wherein the framework beam extends horizontally and consists of two spaced sub-beams 1 a and 1 b. The base plate 2a of a Belleville spring column 2 abuts on the sub-beams. In the Belleville spring column 2, a plurality of Belleville springs 2b is retained between the base plate 2a and a top plate 2c by means of a plurality of cage screws 2d having nuts 2e.

An anchor 3, which is connected to a boiler element (not shown) at its lower end, penetrates the space between the two sub-beams 1 a, 1 b and the Belleville spring column 2, and the anchor 3 is retained on the top plate 2c by means of an anchor nut 4, which abuts on a washer, if necessary, wherein the anchor nut engages with anchor threads 3a in this region. The anchor nut 4 can be associated with a counter nut.

The base plate 5a of a cage or lantern 5, which is one embodiment of the load adjustment assembly LEA, rests on the ends of the cage screws 2d. The top plate 5b of the cage abuts on the base plate via at least one wall element 5c. In the disclosed embodiment, one single wall element is used. According to other embodiments, two or more wall elements can be provided for supporting the top plate. The elements 5a, 5b and 5c are welded together. The base plate 5a has an opening 6, and the top plate 5b has an opening 7, both for the anchor 3 passing through the cage 5. In the shown embodiment, the wall element 5c does not completely surround the anchor 3 but preferably is formed as a divided circle or horse shoe, such that a tool for rotating the anchor nut 4 can be inserted into the space between the base plate and the top plate (at least one laterally extending opening S between the elements 5a, 5b and 5c gives the impression of a lantern or cage, i.e. a lantern having an illumination opening and having a protection against rain and wind).

An annularly formed load cell 8 surrounding the anchor 4 abuts on the top plate 5a of the cage 5, wherein the load cell is connected to a data processing unit 10. Such load cells are distributed e.g. by the company Sisgeo/IT. A load distributor plate 11 having an opening 11a, rests on the load cell, wherein the free end of the anchor 3 having the threads 3a, passes through the opening.

An expansion nut 12 is screwed on the free end of the anchor, wherein the expansion nut abuts on the load distributor plate. When the expansion nut 12 is rotated, an axial tensile force - free of torsion - is exerted onto the anchor 4.

One example of an expansion nut is shown in Fig. 2 in an exploded view. The expansion nut consists of an inner bushing 13 having inner threads 13a corresponding to the anchor threads, an outer bushing 14 and a washer 15. The inner and outer bushings 13,14 are connected via outer threads 13b of the inner bushing and inner threads 14b of the outer bushing. The inner bushing 13 has additional inner threads 13a corresponding to the anchor threads 3a, wherein a thread adaptor can be used, if necessary, e.g. when the anchor threads 3a are smaller than the threads 13a. In a mounted state, the inner bushing 13 and the washer 15 are connected by means of indentations 15b and 13c, such that the inner bushing 13 can move only axially in direction of the axis of the anchor. A correspondingly formed torque screwing device (not shown) can be mounted on the expansion nut so as to transfer a torque via the indentation 14a (having a coarse structure) to the outer bushing. The washer 15 has an outer indentation 15a (having a fine structure) which engages with a corresponding indentation of the screwing device as soon as the torque screwing device is mounted, so as to block a rotation of the washer 15 and the inner bushing 14. As soon as the outer bushing 14 is rotated by means of the torque screwing device, the inner bushing 13 moves upwards and lifts the anchor 3 free of torsion and free of lateral loads. Preferably, the torque screwing device is operated via pressurized fluid and is connected to a hydraulic power unit to this end. The disclosed expansion nut is available e.g. from the company HYTORQ. Other expansion nuts, such as described in the US Patent 7,246,542, can be used for providing torsion free lifting of the anchor as well.

In the embodiment according to Fig. 3, a separate anchor plate 15 is provided, which rests on the framework beam 1, wherein a double roller plate 17 rests on the anchor plate, and wherein a load distributor plate 18 rests on the double roller plate. The anchor passes through these three elements. An anchor nut 4, which holds the anchor, abuts on the load distributor plate 18.

The arrangement for load adjustment, LEA (LEA = Lasteinstellungsanordnung) corresponds to the arrangement shown in Fig. 1, and the same reference signs as in Fig. 1 are used. As soon as the cage 5 is located upon the load distributor plate 18, the anchor nut 4 is inside the cage. The expansion nut 12 is screwed onto the anchor threads 3a and abuts on the load distributor plate.

If, for a particular boiler, the length of the anchor 3 above the anchor nut 4 is not sufficient for mounting the expansion nut, a thread adaptor provided with corresponding threads can be screwed onto the free end of the anchor 3 so as to extend the anchor.

In both embodiments of Fig. 1 and Fig. 3, the cage 5, the load cell 8 and the load distributor plate 11 are initially mounted for adjusting the load, and thereafter, the expansion nut 12 is screwed onto the anchor 3. Then, the anchor 3 is lifted free of torsion by rotating the expansion nut 12 by means of the torque screwing device, wherein the anchor nut 4 is free of load and the load cell 8 receives the load. The lifting distance is e.g. 0,1 mm; the anchor pre-load is not changed. Thereafter, the anchor nut 4 will be untightened (e.g. by about 10 mm), such that the anchor nut 4 does not receive a load during the entire adjustment of the anchor load. The measured value of the load cell will be provided to the data processing unit 10 by means of the measurement line 9. It is stored therein, and from the measured value, the effective force is determined, which is displayed. The determined force is compared to the target value according to the design. By tightening or untightening the expansion nut 12 via the torque screwing device, the anchor load is adjusted to the target value. Thereafter, the anchor nut 4 is tightened. Finally, the expansion nut is released, and the load distributor plate, the load cell and the cage can be removed.

Fig. 4 shows the simultaneous use of a plurality of arrangements for load adjustment LEA on five anchors 3, which carry a boiler element, e.g. a section of a boiler wall. As several anchors are attached to one boiler element (boiler wall, KW (KW = Kesselwand)) and are connected thereto via the boiler wall, mutual influence is possible.

The assemblies for load adjustment, LEAs, at the load locations A, B, C, D and E, each comprise load cells 8-1 to 8-5 and associated cages 5 and expansion nuts 12. The load cells are connected to a central data storage 19 via lines K1 to K5, wherein the data storage collects all measured values of the load cells, stores the measured values, determines the actual forces therefrom, and transfers these values via a Bluetooth connection 20 to a computer having a display 21. By means of the computer, all measured values of all load cells 8-1 to 8-5 are read out in time intervals having a pre-determined length, the measured values are displayed and stored, if necessary. Due to the continuous measurements of all anchor loads, in case of a deviation of the load on one of the anchors, e.g. anchor 3-2, an influence on the loads of the neighboring anchors 3-1, 3-3 and also for the anchors 3-4 and 3-5 may be detected. Due to the influences which have been detected, the load adjustments of the respective anchors can be re-adjusted by re-locating a torque screwing device 22 to some of the anchors, wherein the torque screwing device is schematically shown and operated by pressurized fluid. The torque screwing device 22 is connected to a hydraulic power unit 23.

On the display 22, the target graph of the anchor loads according to the design is shown as a broken line “Target” 24. Furthermore, the real anchor loads, which have been determined from the load measurement, at the load locations A, B, C, D and E (“Actual”) are shown. The anchor loads are adjusted to the target values by tightening or untightening the respective expansion nuts 4. Thereafter, the anchor nuts are tightened. Finally the expansion nuts 12 are released and the load distributor plates, the load cells 8 and the cage 5 can be removed.

The method for load adjustment by using a plurality of assemblies for load adjustment, LEAs, can be divided in the following sub-steps: 1) Calculating the expected bendings and elasticities in the assumed target status (according to the design). This is carried out by means of a detailed modelling of the boiler framework, anchors 3 and the load distributors by means of a Finite-Element-Calculation software. 2) Measuring the real existing loads on the individual anchors 3. This is carried out by means of a load cell 8, e.g. during operation. 3) Updating the theoretical calculated bendings and elasticities by comparison to the real loads. This is carried out by a skilled person on site during the measurement and results in the target forces of the individual anchors. 4) Adjusting the target forces of a group of anchors 3-1 to 3-5, determined under 3). In doing so, new strains occur because of the load variations. 5) Iteratively carrying out the steps 3) and 4) until all target forces are met.

List of Reference signs: 1 framework beam 1a/1b sub-beam 2a base plate 2 Belleville spring column 2b Belleville springs 2c top plate 2d cage screws 2e nuts 3 anchor 3a anchor threads 4 anchor nut 5a base plate 5 cage 5b top plate 5c wall element 5 laterally extending opening of the cage 6 opening (base plate) 7 opening (top plate) 8 load cell 9 measurement line 10 data processing unit (for individual assemblies for load adjustments LEA) 11 load distributor plate 11 a opening (load distributor plate) 12 expansion nut 13 inner bushing 13a inner threads (inner bushing) 13b outer threads (inner bushing) 14 outer bushing 14a indentation (coarse structure) 14b inner threads (outer bushing) 15 washer 15a indentation (fine structure) 16 anchor plate 17 double roller plate 18 load distributor plate KW boiler wall K1-5 wire 19 central data recording 20 bluetooth connection 21 display 22 torque screwing device 23 hydraulic power unit 24 target graph A, B, C, D, E load locations LEA assembly for load adjustment

Claims

Device for load measurement or load adjustment of a boiler structure part (KW) suspended by means of at least one anchor (3) on a kettle or boiler equipment, and the anchor at least at its free end has a thread (3a) and is passed through a anchor plate (2a), and wherein an anchor nut (4) which is directly or indirectly brought into abutment against the anchor plate is screwed onto the anchor and with a cage (5) having an opening (6) into which the anchor can enter the cage, characterized in that the cage (5) comprises a side opening (S) and an opening (7) where the anchor can come out of the cage and that the device has a gripping around the anchor and a pressure measuring box (8) supported by the cage (5) ), a fixed distribution plate (11) abutting against the pressure gauge box with an anchorage opening (11 a), and an anchor gripping, and torsion-free device supporting torsion-free raising of the anchor relative to the anchor plate.

Device according to claim 1, characterized in that the cage consists of a foot plate (5a) with holes for inserting the anchor and insertion of a tool for moving an anchor screw, a main plate (5b) with a hole from which the anchor can be removed. out, and one or more wall member (5c) supporting the main plate of the foot plate and partially enclosing the anchor.

Device according to claim 1 or 2, characterized in that the arrangement for torsion-free raising can be operated hydraulically or electrically.

Device according to one of Claims 1 to 3, characterized in that a pierced double roll plate (17) through which the anchor is passed abuts an anchor plate and that a load distribution plate (18) through which the anchor is passed abuts the double roll plate (17) to which anchor an anchor nut is attached.

Device according to one of claims 1 to 4, characterized in that the anchoring plate has a plate spring suspension (2) and that an anchorage nut abuts an upper plate (2c) on the plate spring suspension.

Device according to claim 5, characterized in that the plate springs between a lower plate (2a) and the top plate (2c) are held by means of cage screws (2e) and that a base plate (5a) of the cage abuts against the screw heads.

Device according to one of claims 1 to 6, characterized in that the arrangement for torsion-free raising consists of an expansion nut (12) having an inner sleeve (13) having an internal thread (13a) corresponding to the anchor thread, an outer sleeve (14) and a washer (15) and an electric or pressure-driven drive torque screwdriver acting on the outer sleeve.

Device according to one of claims 1 to 7, characterized in that a thread-fitting device is provided at the free end of the anchor for adapting the length of the anchor and / or the anchor threads to the requirements of the arrangement for torsion-free raising of the anchor.

Method for load measurement or load adjustment using a load measuring device or load setting according to one of claims 1 to 8, characterized in that the method has the following steps: raising the anchor by turning a resilient nut by means of a torque screwdriver until anchor nut is unloaded, whereby the pressure gauge box is loaded, but loosening the anchor nut to prevent loads of the latter during the anchor load setting determines the anchor load by the measured value provided by the pressure gauge box comparing the mediated anchor load the nominal value of tightening or loosening the resilient nut by the torque screwdriver and this in order to bring the anchor load to the nominal value and tightening the anchor nut.

Method for load measurement or load adjustment by means of a number of devices anchored to an anchor according to one of claims 1 to 8, characterized in that the measured values from the number of devices are searched for in predetermined time intervals in order to recognize load variations, and in the case of deviations of one or more anchor loads from the nominal value, the load on the corresponding anchor (s) is then reset using the corresponding device.