GB2165933A

GB2165933A - Improved plate heat exchanger and frame therefor

Info

Publication number: GB2165933A
Application number: GB08426779A
Authority: GB
Inventors: Derek Ian Finch
Original assignee: APV International Ltd
Current assignee: APV International Ltd
Priority date: 1984-10-23
Filing date: 1984-10-23
Publication date: 1986-04-23
Also published as: GB2165933B; GB8426779D0

Abstract

In order to enable a plate heat exchanger to be disassembled from its tie-bars, there is provided a plate heat exchanger comprising a pack of separable plates held in compression in a frame by tie-bars 22 extending between, and passing through, a head 12 and a movable follower thereof. Each tie-bar 22 being threaded adjacent one end, and the opposite end being provided with a removable locking member in the form of a disc 28 to react against the head 12 or the follower. Disc 28 is held firmly on the tie-bar 22 when reacting against tension forces in the tie-bar 22, but is readily removable when tension is relaxed. Disc 28 has a keyhole slot 30 whose narrow end 34 fits over cutaway 27 in tie-bar 22, and whose wide end 32 is wide enough to allow the disc 28 to be removed from or introduced onto the tie-bar 22. The head 12 or follower has, adjacent the tie-bar apertures, abutments 38 adapted to enter the wide ends 32 of the keyhole slots 30 to engage the disc 28 within the slots 30 and thus restrain the discs 28 and tie-bars 22 against rotation. <IMAGE>

Description

SPECIFICATION Improved plate heat exchanger and frame therefor The present invention relates to plate heat exchangers.

A plate heat exchanger of the type to which this invention relates consists of a pack of separable plates in face-to-face spaced relationship in a frame having peripheral gaskets to define flow spaces between the plates. The frame consists of top and bottom bars extending between a fixed head and a fixed end support. The plates are slidable on the top and bottom bars and are compressed against the head by a follower which is slidable along the top and bottom bars and is linked to the head by threaded tie-bars. In large sized heat exchangers the pack of plates is normally tightened by relative rotation between the tiebars and nuts in engagement therewith.

Conventionally, the tie-bars are mounted in slots in the edge of the head and follower which allows easy fitment and remaoval of the tie-bars. This method of mounting the tie-bars has the disadvantage that the tie-bars tend to fall out of the slots unless held in position by bearing plates which locate on the frame. It also has the disadvantage of presenting fabrication problems and expense, for example, for reinforcement of the slots. If the tie-bars are mounted in apertures in the frame these disadvantages are somewhat mitigated. However, the advantage of easy fitment and removal of the tie-bars is lost since it is necessary to withdraw the tie-bars through the apertures, which require an end clearance adjacent to the frame at least equal to the length of the tiebars.

Thus, it is an object of the present invention to mitigate the disadvantages whilst retaining the advantages of both of the above mentioned methods.

In accordance with a first aspect of the invention, there is provided a plate heat exchanger comprising a pack of separable plates mounted in a frame between a head and a movable follower thereof, the pack of plates being adapted to be held in compression by means of tie-bars extending between and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter to pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower, the locking member being held firmly on the tie-bar when reacting tension forces in the tie-bar, but being readily removable when the tension is relaxed.

In accordance with a second aspect of the invention, there is provided a frame for a plate heat exchanger, the said frame comprising a head and a movable follower between which a pack of plates may be held in compression by means of tie-bars extending between the and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter to pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower. the locking member being held firmly on the tie-bar when reacting tension forces in the tie-bar, but being readily removable when the tension is relaxed.

The removable locking member may have a keyhole slot of which a narrow end fits snugly over a cutaway in the tie-bar, and of which the wide end is wide enough to allow the locking member to be removed from or introduced onto the tie-bar.

The locking members are conveniently in the form of discs.

The head or follower may have, adjacent the tie-bar apertures, abutments adapted to enter the wide ends of the keyhole slots in the removable locking members to engage the locking members within the slots and thus restrain the removable locking members and tiebars against rotation.

The invention will be further described with reference to the accompanying drawngs, in which: Figure 1 is an elevational view of an assembled plate heat exchanger to which the present invention may be applied; Figure 2 is an exploded perspective view of one end of a tie-bar and associated parts in accordance with one form of the invention; and Figure 3 is a view showing the parts of figure 2 in an assembled relationship.

Figure 1 shows a plate heat exchanger which consists of a pack of separable plates 10 in face-to-face spaced relationship in a frame. The frame consists of a top bar 18 and a bottom bar 20 extending between a fixed head 12 and a fixed end support 14.

The plates are slidable on the top bar 18 and bottom bar 20 and are compressed against the head 12 by a follower 16, which is also slidable along the top bar 18 and bottom bar 20. The follower is linked to the head 12 by threaded tie-bars 22. The pack of plates 10 is tightened down by relative rotation between threads 23 at one end of the tie-bars 22 and nuts 24 in engagement therewith.

Figures 2 and 3 show part of the head 12 and one end of one tie-bar 22. In figure 2, the arrangement is shown exploded and with the tie-bar 12 relieved from the tension of maintaining the plate pack in compression. It can be seen that the end of the tie-bar 22 remote from the threads is formed with a pair of parallel flats 26 forming recesses 27 near the end of the tie-bar 22. A removable locking member in the form of a disc 28 has a keyhole slot 30 having a wide end 32 and a narrow end 34. The wide end 34 is wide enough to allow the disc 28 to be introduced over the tie-bar 22 and to be moved therealong. The disc 28 is of a thickness to fit easily but snugly within the recesses 27, and the width of the narrow end 34 of the slot 30 is such as to allow the disc to be fitted into the recesses 27 by engaging, again easily but snugly, the flats 26.This coniditon is illustrated in figure 3.

Thus, when the tie-bar is relieved as shown in figure 2, the disc 28 may be readily assembled onto or removed from the tie-bar 22.

When the pack is compressed, the reaction between the tie-bar 22 and the head 12 is transmitted via the disc 28, and the latter is thus pressed tightly against one edge of each of the recesses 27 by the head 12, and is securely held. In order to restrain the tie-bar 22 against rotation, the wider end 32 of the slot 30 is engaged over an abutment 38 provided on the head adjacent the aperture for the tie-bar. An initial tightening of the tie-bar will bring the side of the slot 30 into engagement with the abutment 38, which will prevent further rotation of the disc 28 and the tie-bar 22, to which it is anchored by the flats 26 engaging the narrow end 34 of the keyhole slot.

Various modifications may be made within the scope of the invention. Thus, while the discs 28 are illustrated as being at the head ends of the tie-bars, they could be at the follower ends thereof. Also, the circular discs 28 could be replaced by a locking member of any suitable shape, e.g, regularly polygonal or rectangular. Further, while the abutment 38 has been shown as having a hexagonal socket, thus implying that it is screwthreaded, and therefore removable, it may be welded or otherwise permanently attached to the head or follower.

Claims

1. A plate heat exchanger comprising a pack of separable plates mounted in a frame between a head and a movable follower thereof, the pack of plates being adapted to be held in compression by means of tie-bars extending between and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter to pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower, the locking member being held firmly on the tie-bar when reacting tension forces in the tie-bar, but being readily removable when the tension is relaxed.

2. A plate heat exchanger as claimed in claim 1, in which the removable locking member has a keyhole slot of which a narrow end fits snugly over a cutaway in the tie-bar, and of which the wide end is wide enough to allow the locking member to be removed from or introduced onto the tie-bar.

3. A plate heat exchanger as claimed in claim 2, in which the head or follower has, adjacent the tie-bar apertures, abutments adapted to enter the wide ends of the keyhole slots in the removable locking members to engage the locking members within the slots and thus restrain the removable locking members and tie-bars against rotation.

4. A plate heat exchanger as claimed in any of the preceding claims, in which the locking members are in the form of discs.

5. A plate heat exchanger substantially as hereinbefore described with reference to the accompanying drawings.

6. A frame for a plate heat exchanger, the said frame comprising a head and a movable follower between which a pack of plates may be held in compression by means of tie-bars extending between and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter such that both ends will pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower, the locking member being held firmly on the tiebar when reacting forces in the tie-bar, but being readily removable when the tension is relaxed.

6. A frame for a plate heat exchanger, the said frame comprising a head and a movable follower between which a pack of plates may be held in compression by means of tie-bars extending between and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter to pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower, the locking member being held firmly on the tie-bar when reacting forces in the tie-bar, but being readily removable when the tension is relaxed.

7. A frame as claimed in claim 6, in which the removable locking member has a keyhole slot of which a narrow end fits snugly over a cutaway in the tie-bar, and of which the wide end is wide enough to allow the locking member to be removed from or introduced onto the tie-bar.

8. A frame as claimed in claim 7, in which the head or follower has, adjacent the tie-bar apertures, abutments adapted to enter the wide ends of the keyhole slots in the removable locking members to engage the locking members within the slots and thus restrain the removable locking members and tie-bars against rotation.

9. A frame as claimed in any of claims 6 to 8, in which the locking members are in the form of discs.

10. A frame for a plate heat exchanger substantially as hereinbefore described with reference to the accompanying drawings.

CLAIMS New claims or amendments to claims filed on 16/10/85 Superseded claims 1 and 6 New or amended claims:

1. A plate heat exchanger comprising a pack of separable plates mounted in a frame between a head and a movable follower thereof, the pack of plates being adapted to be held in compression by means of tie-bars extending between and passing through corresponding apertures in the head and the follower, each tie-bar comprising a shaft threaded adjacent one end and being of a diameter such that both ends will pass through the apertures in the head and the follower, the end of each tie-bar opposite the threading being provided with a removable locking member to react against the head or the follower, the locking member being held firmly on the tiebar when reacting tension forces in the tiebar, but being readily removable when the tension is relaxed.