US2934321A - Connecting plate assembly for plate heat exchangers - Google Patents

Description

April 26, 1960 R. P. L..HYTTE 2,934,321

CONNECTING PLATE ASSEMBLY FOR PLATE HEAT EXCHANGERS Filed May 31, 1955 a sheets-sheet 1 //VVENmR obs/ yonfus [amen Zia fie ATTORNEYS April 26, 1960 LATE ASSEMBLY FOR PLATE HEAT EXCHANGERS TORNEYS April 26, .1960 R. P. L. HYTTE CONNECTING PLATE ASSEMBLY FOR PLATE HEATEXCHANGERS 3 Sheets-Sheet 3 Filid lay 31, 1955 uhl hhnnnhmw Q CONNECTING PLATE ASSEMBLY FOR PLATE HEAT EXCHANGERS Robert Pontus Larsson Hytte, Ljungbusen, Sweden, as-

signor to Aktiebolaget Separator, Stockholm, Sweden, a corporation of Sweden This invention relates to plate heat exchangers and particularly to an improved connecting plate assembly by which fluids can be fed to or withdrawn from the spaces within the pack of plates.

Plate heat exchangers, such as those used for treatment of milk and milk products, wort, beer and other liquids, comprise a plurality of similar heat exchange plates assembled into a pack. It is often desired to supply fluid to or withdraw it from the spaces between the plates at a certain point in the plate pack, this fluid being either the liquid under treatment in the apparatus or a fluid for the treatment of the liquid, such as steam for heating the liquid or water for cooling the liquid. In many instances it is desired to withdraw the liquid from the middle of the plate pack for purposes of filtration, separation, or the like, and to return the liquid thus treated to the same place in the plate pack and to the same corner of the heat exchanging plates from which it was withdrawn.

To effect this supply and/or withdrawal of fiuid, it is common practice to insert a connecting plate at the desired place in the plate pack, the connecting plate dividing the plate pack into separate sections. This connecting plate is provided with one or more pipe connections for carrying the liquid or the other fluid into and/ or out of the plate pack, such pipe connections being located opposite the usual passage holes in the heat-exchange plates. As the latter plates usually are rectangular and the passage holes are located in the corner portions of these plates, the pipe connections of the connecting plates are located in the corner portions of the connecting plates. It is not always necessary, however, that liquid be led in and out at each corner of the connecting plate. Often the liquid is merely passed through the connecting plate to the adjoining plate section, in which case the pipe connections are replaced by a simple pipe.

A connecting plate which is not passed or contacted by the treated liquid or by other fluids may be made of a simple and cheap material, such as cast iron. However, the pipe connections which are passed and therefore contacted by these liquids and by corrosive detergents (when the apparatus is cleaned by means of strong chemicals) must be made of very corrosion-resistant material, as in the case of the heat-exchange plates themselves. It has long been the practice, therefore, to use only high-grade stainless steel for these details.

As these pipe connections in the connecting plates must be of a rather complicated form, they have heretofore been made of cast material which, as previously indicated, is of the stainless type. Such cast corners have the drawback, however, that there often are pores in the casting, and these pores after an initial working must usually be welded in order that the pipe connection may be tight, or to avoid dirt crannies ad bacteria colonies. This repairing is an expensive and troublesome operation which often results in the pipe connection being finally discarded as impossible to repair, after much expensive work has already been performed in efforts to remedy the flaws in the casting.

ted States Patent C i 2,934,321 Patented Apr. 26, 1960 "ice The present invention has for its principal object the remedying of these defects and the provision of an improved connecting plate assembly in which growth of the bacterial culture in the pipe connections is prevented. The pipe connections according to the present invention are in the form of easily exchangeable and detachable units in order to facilitate cleaning and inspection and so as to prevent formation of bacteria colonies in the pipe connections, because such colonies impair the quality of the medium flowing through the plate apparatus.

The invention is illustrated in the accompanying drawings, in which:

Fig. I is a face view of a preferred form of the new connecting plate, showing its pipe connections;

Fig. II is an enlarged sectional view of a corner portion of the connecting plate, showing means whereby the connecting pipe can be attached to the plate through the pipe connection in various angular positions; 1

Fig. III is a sectional view on line III-III in Fig. II;

Figs. IV and V are sectional views of modified forms of the pipe connection, and

Fig. VI is an end view of still another form of the pipe connection.

Referring to Fig. I, the connecting plate 1 is adapted to be inserted between a pair of plates in a plate heat exchanger, as will be readily understood by those skilled in the art. At its corners, the plate 1 is provided with connecting pipe units 2 each of which is held by a releasable device or screw 3 in a semi-circular or arcuate seat 4 of the plate. Each connecting unit 2 comprises a' pipe 5 which fits into the arcuate corner recess formed by a seat 4 of the plate, the axis of pipe 5 being normal to the plane of plate 1. The connecting unit 2 has one or more connecting pipes 6, 7 secured to pipe 5. The latter has at least one threaded hole 8 extending only partly through the pipe wall. As shown in Fig. 2, there are two such holes 8 and 12 displaced at an angle from each other (e.g., on the connecting pipe 5. The screw 3 of each unit 2 extends through a hole in the seat 4 and is screwed into the threaded hole 8 or 12 of the pipe 5. The screws 3 are arranged at a suitable angle (e.g. 45 in relation to the side edges of the connecting plate '1'. By placing the screws 3 at an angle of 45 tothese side edges of the connecting plate and providing each pipe '5 ,with two threaded holes 3 and 12 at an angle of 90 in relation to each other, then the pipe connection 5 may be easily loosened, turned through 90 and tightened again by means of screw 3, so that the out-going pipe 6 or 7 is changed from a horizontal to a vertical position or vice versa, depending upon which position is better suited to the mounting of a certain pipe line. (Compare the connections to the right and to the left at the top of Fig. 1.)

To provide for a plurality of pipe connections, each connecting unit 2 comprises at least three pipes (Figs. I, IV, V and VI), one of which is the pipe 5 and the others including the two side pipes 6, 7. These three pipes are joined so as to form a corner unit of the plate 1. The three pipes 5, 6 and 7 preferably form a 90 angle in relation to each other, the two branch pipes or side con'- nections 6 and 7 both being between the planes of the two opposite faces of connecting plate 1 and forming two separate liquid paths. Thus, the liquid flow to or from the plate pack adjacent one face of plate 1 is led through one side pipe 6, and the liquid flow to or from the plate pack adjacent the other face of plate 1 is led through the other side pipe 7.

The simplest way of joining the pipe parts 5-6 or 5-67, to form a connecting unit 2, is no doubt to weld them together. However, pores or deformations are often formed through thermal stress caused by the welding. According to the present invention, therefore, this welding is replaced by rolling in the side connections 6-7 in the flow pipe (see Figs. II-VT). It is true that in this case the pipe 5 must be constructed with a thicker wall than would otherwise be necessary, but the troublesome welding is avoided. By turning a groove 9 around the hole for receiving each pipe 67, the latter is secured from loosening after it has been rolled into the side hole in pipe 5.

By rolling in the side connections as described, a bad dirt cranny could be formed at their inner ends. To avoid this, each bored hole in the pipe 5 for the side-connection is provided with a stop extending all around the side pipe 6 or 7 and being approximately as deep as the material thickness of the side pipe. When rolling in the pipe 6 or 7, the inner end of this pipe is pressed hard against the stop 10 so that the joint between them is entirely closed and compressed, whereby the inner surface of the pipe connection is quite free from open .joints and dirt crannies. If desired, the junction of stop 10 and pipe 6 or 7 can be subsequently pressed through an additional rolling operation, whereby any risk of traces of the joint being left is avoided.

It is necessary, of course, to divide the two liquid flows in a pipe connection unit 2 having two side pipes 6-7, that is, in a so-called double connection. This can be done by pressing into the flow pipe 5 a disc-shaped partition 11, which preferably is fitted tightly in the pipe .and seated firmly against an internal shoulder 13 between the holes for the side pipes 6 and 7 (Fig. IV), so that leakage is prevented. This partition can also be secured by welding it in the double-connection pipe 5, whereby any risk of mixing the liquids is avoided. In the latter case, the partition may be placed in an inclined position in relation to the pipe 5 as well as to the two outgoing pipes 6-7. Alternatively, the. partition may be S- shaped, as shown at 110 in Fig. V, or Z-shaped as shown at 11b in Fig. VI, whereby the welding to secure the partition and any possible after-finishing of the weld joint are facilitated. At the same time the thickness of the conecting plate 1 can be reduced by these alternatives, because the two out-going pipes 67 may then be arranged with their axes in a common plane normal to and bisecting the axis of pipe 5a (Figs. V and VI). Otherwise, the pipes 6-7 must be displaced'frorn each other in the axial direction of pipe 5 (Fig. IV).

In case the pipe connections 6 and 7 are replaced by a simple fiow pipe affording only one passage (Fig. I), such pipe may be mounted and secured in the connecting plate '1 in the same way as the multiple pipe connections. In any case, each unit 2 includes a pipe 5 extending generally perpendicular to the plane of the connecting plate 1 and having a flow passage affording communication to a heat exchange plate adjacent at least one face of the connecting plate.

The invention is not limited to the embodiment described herein. For example, the recesses formed by the seats 4 for receiving the connecting units 2 at the plate corners may be shaped differently than as shown, the

connecting units being formed to fit these recesses.

The rolling in or rolling operation for joining the pipe parts 6 and '7 to the pipe 5 takes place in such a way that the pipe 6 or 7, which from the beginning has a some what smaller diameter than has the corresponding side hole in the pipe 5, is inserted in this side hole, whereupon a press roller is inserted in the pipe .6 and 7, respectively, and is forced during rolling to press the material of the pipe 6 and 7, respectively, against the wall of the side holes in the pipe 5. As a consequence of this rolling operation, the thickness of material in the pipe 6 and 7, respectively, decreases, while the outer diameter of the pipe 6 and 7, respectively, increases so that the pipe 6 and 7, respectively, is 'at last completely secured to the pipe 5. Such rolling operations for fixing a pipe in the hole of a member is well known in the art and does not require any further explanation.

I claim:

1. For insertion in the pack of plates in a plate heat exchanger, to provide a flow connection with the pack, the combination of a connecting plate having at least one corner portion provided with a peripheral recess, said recess defining a seat in the form of a segment of a cylin der opening laterally toward said corner and extending throughout the thickness of the connecting plate, the axis of said cylinder being normal to the plane of the connecting plate, a pipe connecting unit including a pipe for said flow extending generally perpendicular to the plane of the connecting plate and having a cylindrical surface adapted to fit against said cylindrical segment formed by the seat, said pipe being movable into the recess at a right angle to said axis and being adjustable about the pipe axis to different angular positions relative to said seat, and releasable means for securing said pipe in the recess against said seat in a selected one of said angular positions.

2. The combination according to claim 1, in which said pipe includes a thick-walled tubular part forming said cylindrical surface, said tubular part having at least one side pipe extending at a right angle to the axis of said thick-walled part.

3-. The combination according to claim 1, in which said pipe includes a thick-walled tubular part forming said cylindrical surface, said tubular part having at least one side pipe extending at a right angle to the axis of said thick-walled part, said thick-walled tubular part being located within the confines of an imaginary corner formed by extending the main side and end edges of the plate nearest said corner portion until said edges join each other.

4. The combination according to claim 1, in which said cylindrical surface of the pipe has a plurality of threaded holes, said releasable means including a screw on the connecting plate insertable in a selected one of said holes.

5. The combination according to claim 1, in which said releasable means is a screw on the connecting plate, said plate having side edges and the screw extending at an angle of approximately 45 to said side edges.

6. The combination according to claim 1, comprising also a side pipe branching from said first pipe of the connecting unit, the releasable means constituting a means for securing said first pipe in selected angular positions on said seat and thereby varying the position of said side pipe relative to the connecting plate.

7. The combination according to claim 1, comprising also a side pipe branching from said first pipe of the connecting unit, the releasable means being a screw on the connecting plate, said first pipe having a pair of holes adapted to receive the screw and angularly displaced from each other around said first pipe, whereby the releasable means is operable to secure the first pipe in selected angular positions on said seat to vary the position of the side pipe relative to the connecting plate.

8. Thecombination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe.

9. The combination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe, said partition being welded in the first pipe.

10. The combination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe, the partition being disc-shaped and pressed-tightly in said first pipe.

11. The combination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe, the partition extending at least partly at an angle to a plane normal to the axis of said first pipe.

12. The combination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe, the partition being generally S-shaped.

13. The combination according to claim 1, comprising also a pair of side pipes branching from and communicating with the interior of said first pipe of the connecting unit, and a partition positioned in said first pipe to separate the points at which the side pipes communicate with the interior of said first pipe, the partition being generally Z-shaped.

References (Jited in the file of this patent UNITED STATES PATENTS 910,514 Dilts Ian. 26, 1909 1,174,288 Rosenfeld Mar. 7, 1916 1,368,770 True Feb. 15, 1921 1,622,006 Seligrnan Mar. 22, 1927 2,252,274 Rossheim et a1 Aug. 12, 1941 2,551,393 Pinger May 1, 1951 2,654,352 Schoenfeld Oct. 6, 1953 2,777,674 Wakeman Jan. 15, 1957 FOREIGN PATENTS 25,001 Great Britain Oct. 27, 1910 534,313 Great Britain Mar. 4, 1941

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