Tubular heat exchanger

Tubular heat exchanger comprising

• a tubular sleeve comprising an inlet for the entrance of a product to be thermally treated, and an outlet for the exit of said thermally treated product;
• and
• a first plurality of tubes carrying a heat transfer fluid which are located inside the tubular sleeve;
• the exchanger comprising:
• at least one diaphragm located inside the tubular sleeve which divides the interior of the sleeve into at least two chambers, where said diaphragm comprises a central hole configured for allowing the passage of the product from the inlet to the outlet of the sleeve;
• and where said diaphragm comprises a plurality of holes configured for allowing the passage of the first plurality of tubes carrying the heat transfer fluid through the different chambers of the sleeve;
• and
• a piston comprising a tubular shaft and at least two plates perpendicular to the tubular shaft;
• where said tubular shaft is configured for performing a longitudinal reciprocating movement through the central hole of said at least one diaphragm;
• where the tubular shaft comprises a diameter smaller than the diameter of the central hole and allows the passage of product through the annular space defined between the diameter of the central hole and the outer diameter of the tubular shaft;
• where each plate is located inside each chamber of the sleeve, where each plate comprises at least one hole configured for allowing the passage of the product to be treated;
• and where each plate comprises a plurality of holes configured for allowing the passage of the first plurality of tubes carrying the heat transfer fluid through respective plates.