Cabinet and convection dryer

Cabinet drying in Cebu

A cabinet or tray dryer moves heated air through crop arranged on trays inside an enclosed chamber. It gives processors a controlled alternative to relying only on direct sun and weather. PHilMech described cabinet dryers heated by liquefied petroleum gas or steam boilers as common in Cebu's dried-mango processing industry in 2013, when local processors were working against peak-harvest volume and limited drying capacity.

Mango slices are sensitive to prolonged high heat. The PHilMech account notes that circulating warm air can dry the slices while limiting damage, but slow drying can still lead to case hardening: a firm outer surface enclosing a softer interior. Added syrup complicates drying further. The cabinet is one part of a processing line; it does not itself define slice thickness, syrup treatment, final moisture, packaging or the finished product's shelf life.

A family of machines, not one specification

A cabinet dryer can be a compact batch machine with removable trays or a larger commercial cabinet, and its heat source and airflow system depend on the model. PHilMech traces one local development path: a mango cabinet dryer with a biomass-fed furnace was pilot-tested in 2006, following an adaptation of a multi-commodity solar-tunnel dryer. The agency said both those dryer types became commercially available. Its 2013 account also describes Cebu cabinet dryers using LPG or steam boilers, while a current commercial product listing illustrates an electric batch cabinet with racks.

A tray cabinet should not be confused with the far-infrared/convection hybrid described in the same PHilMech report. The hybrid applied intermittent infrared exposure first, then sent partially dried slices to a convection cabinet for the second stage. Its reported eight-hour total compared with twelve hours for the conventional process belongs to that research arrangement; it is not a guaranteed cycle time for every cabinet dryer.

A second mango application

Cabinet dryers also appear in a different PHilMech application: a pilot-scale system for making pectin from mango peels. In the 2022 journal report, the process dries pressed, washed peel in a cabinet tray-type oven before pulverization and pectin extraction. The report gives 70°C as the selected drying temperature for that particular application. It does not establish a standard capacity or specification for cabinet dryers as a class. This case concerns a by-product process, not the commercial Cebu slice-drying equipment.

This distinction matters when comparing dryers. A source may describe mango slices for a snack, peel for a later extraction, a solar tunnel, a biomass-fed cabinet or a hybrid infrared/convection line. The shared cabinet form organizes product on trays within an enclosure, but loading, airflow, heat delivery and purpose differ. This record names the equipment class and keeps individual studies attached to their own product and setup.

What the record does not standardize

There is no single capacity, tray count, cabinet dimension, temperature or fuel that applies to every machine in this class. The Cebu description covers common industrial practice at the time of the 2013 report; the PHilMech pectin trial is a separate measured case; and a supplier image is only one present-day manufactured example. Equipment specifications should therefore be read from the actual model and process documentation rather than inferred from the words “cabinet dryer.”