Heat exchanger containing a component capable of discontinuous movement

Abstract

Regenerative heat exchangers are described for transferring heat between hot and cold fluids. The heat exchangers have seal-leakage rates significantly less than those of conventional regenerative heat exchangers because the matrix is discontinuously moved and is releasably sealed while in a stationary position. Both rotary and modular heat exchangers are described. Also described are methods for transferring heat between a hot and cold fluid using the discontinuous movement of matrices.

Description

FIELD OF THE INVENTIONThis invention is related to regenerative heat exchangers.BACKGROUND OF THE INVENTIONHeat exchangers are devices used to transfer heat between a hot fluid stream and a cold fluid stream. In conventional heat exchangers the heat is transferred from one stream to another through a wall and the heat transfer is limited by the conductivity of the material of which the wall is made.Regenerative heat exchangers typically are capable of achieving higher heating temperatures. Regenerative heat exchangers expose a heat-absorbing mass or matrix alternately to a hot stream and to a cold stream. In general, therefore, regenerative heat exchangers have periodic flow.Periodic-flow exchangers operate differently from conventional fixed-surface heat exchangers in that heat is transferred from the hot fluid to the cold fluid by alternatively heating and cooling a high surface area matrix material. This matrix or core is either rotated through or shuttled back and forth between ...

AI Technical Summary

Benefits of technology

According to the invention the seal leakage rate of a heat exchanger is reduced by discontinuously moving either the matrix or ducting while releasably isolating portions of the matrix with sealing members. In one embodiment of the invention a regenerative heat exchanger for transferring heat between a hot fluid stream and a cold fluid stream has a matrix defining a first group of passageways for fluid to flow therethrough. A seal means is provided capable of releasably sealing the matrix so that said passageways are interconnected with one of said hot or said cold fluid stream. Means are provided for causing discontinuous movement of the matrix relative to said hot or cold fluid streams and relative to the seal means, and the seal means seals only when said matrix is stationary with respect to said seal means.

Generally, the invention provides an improvement in a method of exchanging heat between a hot fluid stream and a cold fluid stream in a regenerative heat exchanger having a matrix with first and second passageways for said hot and cold fluid streams respectively and said heat exchanger having sealing means to seal said hot and cold streams from each other. The improvement comprises sealing the hot and cold fluid streams from each other to prevent mixing of said fluids when the matrix is stationary with respect to the position of the fluid streams and releasing the seal and moving the matrix with respect to the position of said fluid streams to exchange heat through said matrix.

It is a feature of this invention that the sealing of the matrix during the stationary phase reduces the amount of fluid leaking from one side of the seal to the other which significantly reduces the seal leakage rate.

It is an object of this invention to provide a regenerative heat exchanger that shares the benefits of conventional rotary heat exchangers while significantly reducing the leakage rate of such conventional rotary heat exchangers.

It is another object of this invention to provide a rotary heat exchanger that shares the benefits of conventional rotary heat exchangers while significantly reducing the leakage rate thereby.

Problems solved by technology

In conventional heat exchangers the heat is transferred from one stream to another through a wall and the heat transfer is limited by the conductivity of the material of which the wall is made.

In tubular or plate fin type heat exchangers, problems can be encountered if the passages are small because deposits from the hot and cold fluids can accumulate and block the small passages.

In addition, because hot and cold-stream separation is controlled by the seals rather than by complex ducts that are required in recuperators, the cost of making many small passages is low.

In contrast, with fixed surface heat exchangers, achieving both compactness and large, interleaved flow areas simultaneously is more difficult.

A problem encountered with conventional rotary regenerators is leakage of fluid from the exchanger which decreases its efficiency.

This leakage, although relatively small, worsens as the speed of rotation of the matrix increases.

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