Spiral Heat Exchangers

Spiral heat exchangers may be a helical tube configuration, commonly the term denotes to a couple of surfaces which are coiled to create the two channels in a counter-flow arrangement. Each of the two channels has one long curved path. A couple of fluid ports are linked tangentially to the outer arms of the spiral, and axial ports are familiar, but elective.

Concept and Application

The positive is that of the SHE, highly efficient use of the space. This attribute is time and again leveraged and partly reallocated to get other improvements in performance, according to familiar tradeoffs in heat exchanger design. A compact SHE may be employed to have a smaller footprint and thus lower all-around capital costs, or an ever-sized SHE may be used to have less pressure drop. Less pumping energy, higher thermal efficiency and lower energy costs.

The Advantages of Spiral Heat Exchangers

There are several advantages of spiral heat exchangers such as self cleaning, low fouling, easy access and small space requirements. The scrubbing effect in each lone channel removes deposits as they form. Suspended solids seem to settle during low flow rates or shut down, which frequently directs to clogging in multiple channel designs. This cleaning feature is predominantly beneficial to battle clogging in a horizontally mounted unit. Particles tend to build up in the bottom of each channel curvature. This resulting constraint of the channel cross section augments the fluid velocity at the exact area affected and any deposits are instantly flushed away.

The high turbulence fashioned by the incessantly curving channels reduces fouling and scaling tendencies. This means that the spiral design gets better heat transfer surface than a shell and tube heat exchanger. Moreover this also means that the design needs less frequent cleaning.

Accessible and Minimum Space Necessity

Removing the covers on both ends of the spiral heat exchanger formulates the whole length of each of the channels easily accessible for inspection or mechanical cleaning, if required. Should scaling or fouling happen, crackdown in place is useful without even opening the unit.

The circular arrangement of the two channels makes an enormously compact heat exchanger. For instance, 100m2 of heat transfer surface fits into a heat exchanger only one meter in diameter and 1.5 meters long. The only service space required is that for the removal of the covers. Hence efficient performance of the spiral heat exchangers make them very much in demand as the application is suitable for such liquid to liquid duties. 

Questions:

• Define spiral heat exchangers.
• State the role of spiral heat exchangers.