WO2017048143A1

WO2017048143A1 - Heat exchanger

Info

Publication number: WO2017048143A1
Application number: PCT/PL2016/000102
Authority: WO
Inventors: Marek KRAJCZYŃSKI
Original assignee: Enbio Technology Sp. Z O.O.
Priority date: 2015-09-15
Filing date: 2016-09-13
Publication date: 2017-03-23
Also published as: PL413988A1; PL3350532T3; EP3350532B1; PL228879B1; EP3350532A1

Abstract

The heat exchanger having a number of horizontal multi-duct pipes (1) running parallel, with corrugated ribs (2) formed between the pipes, where both ends of the pipes are inserted in the vertical pipe collectors (3, 7) fitted with at least one horizontal partition each and where one of the pipe collectors serves as the manifold (3), in which the upper inlet stub pipe (5) and lower outlet stub pipe (6) are fitted, with a tight horizontal partition (4) going in between is characterized in that the first pipe collector serving as the manifold (3) is higher than the second pipe collector (7), extends below the set of the multi-duct pipes (1), and is fitted with an additional stub pipe (8) in its bottom part, where there is a vertical separating plate (9) fitted below the horizontal barrier (4).

Description

Heat exchanger

The invention concerns a heat exchanger designated to work as a condenser, particularly in steam autoclaves used for sterilisation of loads of different types. The exchanger is installed in the system of cooling the steam pumped out of the pressure process chamber of a steam autoclave.

Known are different types of heat exchangers, the construction of which depends on numerous factors, primarily on the function they serve and their use. Among various structural types of pipe heat exchangers in which one of the agents participating in heat exchange flows inside the pipes and the other agent flows around the pipes, known are solutions in which there is a set of horizontal pipes connected on both sides to the collector pipe collecting one of the agents, while the other agent flows between the pipes, where there are ribs of different kinds formed in the space between the pipes in order to increase the heat exchange surface. Also known are many solutions of heat exchangers in which the flow ducts are drilled in monolith slabs or formed by connecting appropriately profiled plates.

Known from international patent application published under No. WO2011/046650 is a multi-duct heat exchanger for heating, ventilation, air- conditioning, or cooling installations. It has a package of multi-chamber pipes running parallel to each other, between which corrugated ribs are formed. The ends of the pipes on both sides are inserted in vertical collectors with an inlet and outlet for the agent flowing in the pipes. In this solution pipe ends are inserted in the collectors at varying depths and have different shapes, depending on the distance from the inlet of the circulating agent.

Known from European patent application published under No. EP0351938 is a heat exchanger fitted with numerous flat horizontal elements with hollows moulded therein to form ducts, where the ends of those elements are inserted in the vertical collector pipes through slots and where the vertical collector pipes have horizontal partitions, as well as a circulating agent inlet and outlet. Corrugated ribs are squeezed in between the horizontal pipe elements. The solution also discloses a method of making and connecting, one to another, the aluminium ducted pipes, the collector pipes and their covers, and the corrugated ribs.

International patent application published under No. WO2013/162222 discloses a heat exchanger fitted with flat horizontal pipes inside which there are ribs dividing the space inside the pipes into micro-ducts. The flat horizontal pipes run through vertical radiators, and their ends are inserted in vertical collecting pipes which serve as collectors, one of which is fitted with inlet and outlet stub pipes, and both of which are fitted with horizontal partitions. Presented are different variants and structural details of the horizontal partitions inside the collectors.

Furthermore, known from Polish patent application No. PL193959 is a heat exchanger and a method of producing it. The exchanger is fitted with a number of extruded profile pipes running parallel, ends of which are fitted in collector pipes, with a system of fin-type ribs installed between the surfaces of two adjacent pipes. On the outside of the profile pipe, between the collector pipe and the fin system, there is at least one barrier to stop escape of the solder, positioned perpendicular to the pipe. Also disclosed is the method of producing the profiled pipe and forming the barrier thereon.

The heat exchanger having a number of horizontal multi-duct pipes running parallel, with corrugated ribs formed between the pipes, where both ends of the pipes are inserted in the vertical pipe collectors fitted with at least one horizontal partition each and where one of the pipe collectors serves as the manifold in which the upper inlet stub pipe and lower outlet stub pipe are fitted, with a tight partition going in between, according to the invention is characterised in that the first pipe collector serving as the manifold is higher than the second pipe collector, extends below the multi-duct pipe set, and is fitted with an additional stub pipe in its bottom part, where there is a vertical separating plate fitted bellow the horizontal partition.

The separating plate is tightly connected to the horizontal partition, touches on the manifold walls and is placed between the outlets of the multi-duct pipes and the outlet stub pipe.

The horizontal partition is fitted at mid-height point of the multi-duct pipe set, and the separating plate extends lower than the lowest multi-duct pipe.

The height of the manifold extension is at least equal to the height of the multi-duct pipe set. In horizontal section of the exchanger the angle formed between the line of the separating plate and the axis of the outlet stub pipe is acute.

Preferably, the angle between the line of the separating plate and the axis of the stub pipe falls within the range of 35° to 40°.

The horizontal axis of the outlet stub pipe is perpendicular to the horizontal multi-duct pipes.

Preferably, the separating plate is made of aluminium and is soldered to the aluminium horizontal partition, where the horizontal partition is soldered to the aluminium manifold.

The solution according to the invention is advantageous in that it ensures optima! working conditions for the heat exchanger, in particular when used in a steam autoclave, thanks to the separation of the condensate of steam cooled down in the exchanger from the cooled air discharged through the outlet stub pipe, as well as thanks to the guaranteed discharge of the condensates from the exchanger.

An exemplary embodiment of the heat exchanger is illustrated on a drawing, where Fig. 1 presents a conceptual axonometric view of the exchanger, Fig. 2 shows the side view seen from the stub pipes, Fig.3 presents the B-B vertical section across the manifold pipe, and Fig. 4 depicts the C-C horizontal section of the exchanger at the level of the bottom outlet stub pipe.

In the exemplary embodiment the heat exchanger according to the invention consists of a set of flat horizontal multi-duct pipes 1 made of aluminium, open ends of which are inserted in the slots in two aluminium vertical collector pipes of circular cross-section, and soldered in place. The chambers inside the flat multi-duct pipes 1 are formed into a set of parallel ducts less than 1 mm in height, forming micro-ducts for the first circulating agent. Formed in between the surfaces of two adjacent multi- duct pipes 1 are aluminium corrugated ribs 2 around which the other circulating agent flows. The first pipe collector serves as a manifold 3 and features a horizontal partition 4 fitted at mid-height point of the set of the mu!ti-duct pipes 1, Partition 4 is made of aluminium and is tightly soldered to the walls of manifold 3. The pipe of manifold 3 is fitted with the top inlet stub pipe 5 positioned above the horizontal partition 4, and the bottom outlet stub pipe 6 positioned under the horizontal partition 4. Both stub pipes are fitted so that their axes, when in horizontal section of the exchanger, are perpendicular to the ducts in the horizontal multi-duct pipes 1. The second vertical pipe collector 7 corresponds in height with the set of the multi- duct pipes 1, it has no partitions inside and is closed on both ends with aluminium covers soldered thereto. The first vertical pipe collector which serves as manifold 3

100 is extended at the bottom reaching below the set of the multi-duct pipes 1 so that the total height of the manifold 3 is approximately twice the height of manifold 3 in the area of the pipe set. In its lowest section manifold 3 is fitted with the third, additional stub pipe 8 the horizontal axis of which is parallel to the axes of the inlet stub pipe 5 and the outlet stub pipe 6. Manifold 3 is closed on the top and bottom

105 with aluminium covers soldered thereto. Inside manifold 3, along its diameter and under the horizontal partition 4 there is a vertical rectangular aluminium separating plate 9 soldered along its top edge to the bottom of the horizontal partition 4, and its vertical side edges touch on the walls of manifold 3. The separating plate 9 is placed inside manifold 3 between the outlets of the multi-duct pipes 1 and the outlet stub

110 pipe 6, and ends below the set of multi-duct pipes 1, i.e. below the level of the lowest horizontal pipe. In the most advantageous variant of the invention embodiment the separating plate is positioned at the angle of 35° with respect to the stub pipe axes. In the exemplary embodiment the set of multi-duct pipes 1 is made up of nine flat horizontal pipes with a number of micro-ducts no more than 1 mm in height. The

115 approximate dimensions of the set are: length 120 mm, width 22 mm, height 60 mm; manifold diameter 3, the second vertical pipe collector 7 and the horizontal partition are 30 mm, the height of the second vertical pipe collector is 70 mm, and the total height of the manifold is 132 mm. The height of the separating plate 9 is 33 mm.

Depending on the use and needs, the heat exchanger according to the

120 invention in different embodiment variants can have various dimensions and various arrangements and shapes of the horizontal pipe ducts between the vertical collectors and ribs between the ducts, as well as additional horizontal partitions in the other vertical collector, plus additional partitions in the manifold above the partition with the vertical separating plate, thanks to which the route of the steam through the

125 ducts of the exchanger is longer.

The exemplary heat exchanger is particularly designated for and installed in the cooling system of a steam autoclave class B in which the sterilisation process advances in sequences of vacuum and steam injections, with steam overpressure maintained so as to heat up the load and sterilize it, followed be a sequence of

130 underpressure to dry the sterilised load. Superheated steam is extracted from the autoclave process chamber with a vacuum pump. The correct operation and life of the vacuum pump, and the total process time are determined by the cooling the extracted from the chamber to the lowest possible temperature and drying it to the maximum possible extent. That is why the steam extracted from the process

135 chamber is first fed to the heat exchanger in which it cools down and condenses, before it reaches the vacuum pump. Chambers of flat horizontal multi-duct pipes 1 serve as the ducts through which the first agent circulating in the heat exchanger, that is steam, flows, where the other agent is the air which flows between the corrugated ribs 2 and cools down the superheated steam. In order to improve

140 efficiency of the cooling process the flow of air is forced with ventilators.

Superheated steam ca. 135°C is supplied through the conduit connected to the inlet stub pipe 5 into the manifold 3 over the horizontal partition 4, from where underpressure causes the air to flow through parallel micro-ducts formed in the flat multi-duct pipes 1 to the second vertical pipe collector 7 and flows back to the

145 manifold 3 through micro-ducts, under horizontal partition 4, from where the air, cooled down to 60°C and dried, is discharged to the vacuum pump through the outlet stub pipe 6. The cooled air flowing into the manifold 3 can contain condensates spraying from the micro-ducts, which are undesirable in the air discharged through the outlet stub pipe 6, since they affect the efficiency and life of the vacuum pump.

150 Condensates accumulating in the exchanger affect its efficiency too, as they reduce the size of the heat exchange surface. The separating plate 9 used in the exchanger prevents infiltration of the condensates from the micro-ducts of the flat profiled pipes 1 to the outlet stub pipe 6, and from there to the vacuum pump, and instead directs the condensates to the extended bottom part of the manifold 3, where the

155 extended bottom part serves as the condensate collector tank from where they are discharged through an additional stub pipe 8 playing the function of the condensate outlet stub pipe. The condensates are discharged in the subsequent cycle, in which at the beginning of the process of emptying the autoclave process chamber the overpressure in the chamber is used to push the condensate out, while the mouth of

160 the outlet stub pipe 6 leading to the pump is closed. The separating plate 9 does not close the circulation entirely, the dried air flows under the plate and can be transported to the vacuum pump through the outlet stub pipe 6.

The structure of the heat exchanger according to the invention ensures optimal working conditions for the autoclave cooling system thanks to elimination of

165 condensate accumulation in the heat exchanger. This translates to shorter time needed for drying the process chamber after the sterilization p roper, and this reduces the total duration of the sterilization process. At the same time, preventing water access to an autoclave vacuum pump ensures its maximum efficiency and extends its life.

The heat exchanger according to the invention can also be used in many other systems in which it plays the function of a condenser, and which require separation of the condensates from the cooled circulating agent.

Claims

1. The heat exchanger having a number of horizontal multi-duct pipes (1) running parallel, with corrugated ribs (2) formed between the pipes, where both where both ends of the pipes are inserted in the vertical pipe collectors fitted with at least one horizontal partition each and where one of the pipe collectors serves as the manifold (3) in which the upper inlet stub pipe (5) and lower outlet stub pipe (6) are fitted, with a tight horizontal partition (4) going in between, characterized in that the first pipe collector serving as the manifold (3) is higher than the second pipe collector (7), extends below the set of the multi-duct pipes (1), and is fitted with an additional stub pipe (8) in its bottom part, where there is a vertical separating plate (9) fitted below the horizontal partition (4).

2. The heat exchanger accordingto Claim 1, characterised in that the separating plate (9) is tightly connected to the horizontal partition (4), touches on the walls of manifold (3) and is placed between the outlets of the multi-duct pipes (1) and the outlet stub pipe (6).

3. The heat exchanger according to Claim 2, characterised in that the horizontal partition (4) is fitted at mid-height of the set of the multi-duct pipes {1), and the separating plate (9) extends lower than the lowest multi-duct pipe (1).

4. The heat exchanger according to Claim 3, characterised in that the height of the extension of manifold (3) is at least equal to the height of the set of the multi-duct pipes (1).

5. The heat exchanger according to Claim 4, characterised in that in horizontal section of the exchangerthe angle formed between the line of the separating plate (9) and the axis of the outlet stub pipe (6) is acute.

6. The heat exchanger according to Claim 5, characterised in that the angle between the line of the separating plate (9) and the axis of the outlet stub pipe (6) in the horizontal section of the exchanger falls within the range of 30° to 40°.

7. The heat exchanger according to Claims 5 or 6, characterised in that the horizontal axis of the outlet stub pipe (6) is perpendicular to the horizontal multi-duct pipes (1).

8. The heat exchanger according to Claims 2 - 7, characterised in that the separating plate (9) is made of aluminium and is soldered to the aluminium horizontal partition (4), where the horizontal partition is soldered to the aluminium manifold (3).