GB2189449A

GB2189449A - Extraction of tubes from condensers

Info

Publication number: GB2189449A
Application number: GB08604772A
Authority: GB
Inventors: William Henry Taylor; David Gerald Taylor
Original assignee: TAYLOR BROTHERS
Current assignee: TAYLOR BROTHERS
Priority date: 1986-02-26
Filing date: 1986-02-26
Publication date: 1987-10-28
Anticipated expiration: 2006-02-26
Also published as: GB8604772D0; GB2189449B

Abstract

A method and apparatus for extracting tubes from a condenser in which the tube end is gripped between a pair of rollers 15, 16 each having a circumferential groove, the two rollers having connected gear pinions 25 to cause simultaneous rotation in opposite directions. The two rollers can be moved towards each other to grip the condenser tube by means of a cam or crank 32 controlled by a hand lever 34. A spacer tube (36, Figure 2) is fitted over the projecting end of the condenser tube and the rollers are turned by an air motor 30. <IMAGE>

Description

SPECIFICATION Extraction of tubes from condensers This invention relates to methods and apparatus for extracting Condenser tubes. In a normal Condenser forming part of a large boiler installation in a power station for example, there may be as many as 20,000 tubes each 50- 100 fit. in length. It may be required to withdraw some or all of the tubes for maintenance purposes or at the end of the life ofthe Condenser the tubes may have to be withdrawn for scrap.Each tube normally passes through 5 or 10 sets of apertured sagger plates and the corrosion which forms on the tubes, makes withdrawal through the plates extremely difficu It. Many different procedures have been adopted to extract the tubes but existing methods are slow, laborious, expensive and sometimes cause unacceptable damage to the tubes or the end plates. Accordingly it is an object of the invention to provide improved procedures and equipment for extracting the tubes.

Broadly stated from one aspect the invention consists in a method of extracting tubes from a Condenser in which the tube is gripped between a pair of rollers shaped to engage opposite sides ofthe tube and the rollers are turned in unison to extract the tube.

According to a preferred feature of the invention the rollers are formed with ribs orteeth to assist in gripping the tu be.

Preferably the rollers are moved towards each other to grip the tube and conveniently there is a spacer whereby the rollers may be held away from the end plateoftheCondenserduringthetube pulling.

From anotheraspectthe invention consists in apparatus for extracting tubes from a Condenser, comprising a pair of co-operating rollers on parallel axes formed to engage and grip the opposite sides of atube, meansfor rotatingthetubes in unison and means for moving one roller relative to the otherto increase the grip on the tube.

Preferably the rollers are provided with meshing teeth capable of allowing for some movement of the rollers towards and away from each other.

In a preferred construction one ofthe rollers is mounted on an eccentric pintle and the apparatus includes meansforturning the pintletovarythe position of the roller axis.

The tube puller of the invention preferably includes a power operated motor for driving the rollers, and the rollers are preferably mounted in a casing having athrough apertureto allowformovementof the tube, and including atubularspacerto holdthe casing clear of the end plate of the Condenser.

The invention may be performed in various ways and one specific embodiment with some possible modifications will now be described byway of example with reference to the accompanying drawings in which Figure lisa diagramatic side view of part of a Condenser showing one ofthe Condensertubes initiallywithdrawn a short distance, Figure2 is a diagramatic side elevation showing a tube pulleraccording to the invention in position against the end plate of the Condenser, Figure 3 is a diagramatic end view also in section illustrating the tube puller of the invention in position on the tube, Figure4is a detailed end view of one ofthe rollers ofthetube puller, Figure 6is a diagramatic side elevation of the adjusting eccentric, and Figure 6illustrates the teeth of one of the rollers, on an enlarged scale.

In the Condenser illustrated in Figure 1 thetubes 10 are mounted between sets of end plates 11 with intervening sagger plates 12 all formed with multiple apertures accurately aligned to accommodatesome 20,000 tubes. As explained it may be necessaryto extract some or all of the tubes for various purposes and in this example of the invention, the first stage in the process is to withdraw one tube 13 a limited distance 'x' away from the end plate 11. This may be achieved conveniently by inserting a toothed mandrelwhichcomprisesajammingwedgeto penetrate and lock against the inner surface of the tube after which a powerful pneumatic ram is applied to withdraw the tube by a series of hammer blows, as shown in Figure 1.

The high speedtube puller of this example ofthe invention is then applied to extract the whole tube.

This comprises a pair ofspeciallyformed rollers 15, 16 mounted on parallel axes 17,18 in a casing 19 which is formed with a through passage 20 to allow the tube to pass through the casing between the two rollers. Each of the rollers is formed with a peripheral groove 21 of part-circular profile to match the diameter of these Condenser tubes, and the operative surface of each groove 21 is formed with sharp ribs orteeth 22. As shown in Figure 6these teeth are steep edged on oneflankwhilethe opposing flank is inclined thus providing the equivalent of a buttress which gives a grip on the tube which automatically deepens when the resistance increases.Each of the rollers is also formed with or attached to a pinion 25, the teeth of the pinions being of sufficient radial depth to give meshing engagement and allowforsome movement ofthe pinions towards and away from one another.

The lower roller 16 is mounted on a fixed hollow bearing 28 and the casing 19 is secured to a high powered high speed air motor 30 arranged to drive the rollerthrough a reduction gear 31. The other roller 15 is adjustable towards and away from the firstrollerandforthis purpose is mounted on an eccentric pintle 32 carried by a spindle 33 which is located in fixed bearings in the casing,the spindie being provided with a manual lever 34forturning the eccentric and hence adjusting the grip of the rollers on the tube.

In use the casing 19 is provided with a rigid spacer tu be 36 which fits over the end of the Condensertube 13 and holds the casing clear of the end plate 11 of the Condenser. With the end ofthe Condensertube in position between the rollers the lever 34 is turned so that the rollers grip the tube tightly and the motor is then started causing rapid and continuous extraction of the tube through the sagger plates.

Claims

1. A method of extracting tubes from a Condenser in which the tube end is gripped between a pair of rollers shaped to engage opposite sides of the tube and the rollers are turned in unison to extractthe tube.

2. A method according to claim 1 in which the rollers are formed with ribs or teeth to assist in gripping the tube.

3. A method according to claim 1 or claim 2 in which the rollers are moved towards each otherto grip the tube.

4. A method according to any of Claims 1-3 in which the rollers are held awayfrom the end plate of the Condenser during the tube pulling.

5. Apparatus for extracting tubes from a Condenser, comprising a pair of co-operating rollers on parallel axes formed to engage and grip the opposite sides of a tube, means for rotating the tubes in unison and meansformoving one rollerrelativeto the other to increase the grip on the tube.

6. Apparatus according to claim 5 in which the rollers are provided with meshing teeth capable of allowingforsomemovementofthe rollerstowards and away from each other.

7. Apparatus according to claim 5 or claim 6 in which one of the rollers is mounted on an eccentric pintle and including means forturning the pintleto vary the position of the roller axis.

8. Apparatus according to any of claims 5-7 in combination with a power operated motorfor driving the rollers.

9. Apparatus according to any of claims 5-8 in which the rollers are mounted in a casing having a through aperture to allow for movement ofthetube, and including a tubular spacerto hold the casing clear of the end plate ofthe Condenser.