SU1571390A1 - Shell-and-tube evaporator - Google Patents

Abstract

This invention relates to heat engineering. The purpose of the invention is to intensify heat exchange and reduce metal intensity. The shell-and-tube evaporator contains a horizontally placed body 1, in which the heat exchange tube bundle is shifted to one of the sides with the formation of a space 9 between it and the body on the other side. The tube bundle is made in the form of a polyhedron, with all but two faces being tubular baffles 8 formed by tubes of increased diameter, ensuring their contact. One of the mentioned faces, lower horizontal, is the entrance of a liquid refrigerant into the tube bundle and contains pipes of primary and enlarged diameters, with parallel inclined channels 12 formed from the latter, directed toward the second face 7, which is an outlet only the pipe of the main diameter and located above the horizontal axis, adjacent to the space 9 between the tube bundle and the body. In this space, an external circulation circuit of the cooling fluid is formed, which intensifies the flows inside the beam. 1 hp f-ly, 2 ill.

Description

external circulation loop is developed

xc

a chaff fluid that intensifies the flow inside the beam. 1 h. item f-ly, 2 ill.

The invention relates to heat engineering and can be used in ammonia refrigeration units.

The purpose of the invention is to intensify heat transfer and reduce metal consumption.

t

heat exchange device.

Figure 1 shows the shell-and-tube evaporator, a longitudinal section; figure 2 - section aa in figure 1.

The shell-and-tube evaporator contains a cylindrical, horizontally disposed body 1 with tube grids 2 fixed to it, the ends of the evaporator are closed with lids 3 and 4. Cr | hyshka 3 has a nozzle 5 for entry and a nozzle 6 for exit heat-transfer fluid. In tube sheets 2, a bundle of heat exchange tubes 7 of the main diameter and tubes 8 of an enlarged dia- is fixed, providing contact between adjacent tubes with the formation of tube partitions. In the vertical section, the bundle of heat exchange tubes 7 has the shape of a polyhedron, with tubes of increased diameter 8 limiting the bundle across all faces to the bottom and one of the side faces located above the horizontal axis of the heat exchanger and adjacent to the space 9 of the heat exchange bundle pipes 7 from the axis of the housing. The pipes 8 have rolled rollers up to the diameter of the main pipes for a length approximately equal to two thicknesses of the tube plate. In the upper part of the housing 1 there is a pipe 10 for draining refrigerant vapor, and in the lower part there is a pipe 11 for supplying a liquid refrigerant.

A part of the pipes of the lower horizontal face is also made of pipes of increased diameter and placed in alternating order with the pipes of the main diameter. Inside the bundle of heat exchange tubes 7, there are also parallel to one another and installed with an inclination towards the face that has tubes of the main diameter, and channels 12, with the outermost tube of these

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five

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five

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five

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five

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five

The baffles is one of the pipes of increased diameter.

Shell and tube evaporator works as follows.

In the heat exchange process, in the space 9 between the heat exchanger tube bundle and the housing, an external refrigerant circuit is created. The liquid, separated from the vapor-liquid mixture, emerging from a face that does not have a pipe septum, consisting of pipes 7 of the main diameter, is lowered to the bottom of the body, passing further into the heat exchange beam through the slots of the lower horizontal face into the channels 12. Filling the channels The liquid begins to boil due to heat exchange with the brine circulating in the pipes, forming a vapor-liquid mixture that moves towards the face that does not have a pipe partition. At the exit from this face, the steam rushes upwards to the outlet pipe of the evaporator, rotates 180 °, and the liquid, as indicated above, returns downward along the external circulation loop.

The liquid falling out of the vapor to the upper horizontal partition flows to the side of the tube sheets, gradually evaporating due to heat exchange with the brine circulating in the pipes. The residual liquid is drained into the lower part of the body at the tube sheets in the zone of transition of the pipes from the increased diameter to the main one and returned to the heat-exchanging bundle.

The proposed evaporator (compared to the known) has the best thermal performance, as well as smaller dimensions and weight.

Claims (2)

1. Shell-and-tube evaporator, mainly of a refrigeration unit, containing a horizontally arranged cylindrical body with tube grids attached to it, an axisymmetric beam of heat exchange tubes, having a vertical section the shape of the polyhedron, the upper and L lower edges of which are horizontal, and the lateral sides obliquely, with some pipes having an enlarged diameter ensuring contact between adjacent pipes with the formation of pipe partitions located on the periphery of the beam above the horizontal axis of the body, on the lower lateral faces, as well as inside the beam, characterized in that, in order to intensify heat exchange and reduce metal consumption, the vertical axis of the heat-pipe tube bundle is shifted relative to the vertical axis of the body to form discharge side of the space between the beam and the housing, all the faces of the pipe, located above the horizontal axis than the side the faces facing the said space are also made with an enlarged diameter, forming additional pipe partitions along the periphery of the beam, and some of the pipes of the lower horizontal face are also made with an increased diameter and placed in alternate order with the pipes of the main diameter. 2. The evaporator is distinguished in that the pipe partitions inside the beam are parallel to one another and are installed with an inclination in the direction of the said upper edge of the pipes of the main diameter, and the extreme lower pipe of each of these partitions is one of the pipes of increased diameter of the lower horizontal facets.