Heat Exchangers

Viscosity and particulates decide it. Thin, clean liquids run best through plates, products with pulp or small particles need tubular designs, and very viscous or crystallising products require scraped surface machines. If your product changes character with temperature, size the exchanger for its most viscous state, not its average.

Ask for a recent pressure test, inspect plates for cracking and corrosion around the ports, and check gasket age since rubber hardens over time regardless of use. Confirm the plate material suits your product, particularly chloride levels which attack standard stainless grades. Frame condition and tightening dimension records indicate how carefully the unit was maintained.

Plate exchangers are the most flexible, since adding or removing plates within the frame's capacity changes the thermal duty. Tubular and scraped surface units are essentially fixed, so buy them against your actual flow rates and temperature programme. Sellers can usually supply the original thermal design sheet, which is the document your process engineer will want.

Exchangers must be cleaned in place at flow rates high enough to scour the product channels, which sometimes exceeds the production flow rate. Confirm your CIP set can deliver the required flow and temperature before finalising the purchase. Scraped surface machines also need periodic blade and seal inspection as part of the hygiene routine.

Because listings are machines sellers already hold, delivery is usually a matter of transport arrangements rather than manufacturing lead time. You agree collection or delivery terms directly with the seller during the enquiry. For urgent duty replacements this speed advantage over new build lead times is often the deciding factor.