Steps of Square-Type Vacuum Drying / Vacuum Tray Dryer Equipment
The production of square-type vacuum drying equipment starts from design and material cutting, and proceeds through welding, machining, assembly, pressure testing, and trial operation. The following are the 12 steps:
- Design drawing and material procurement: Complete the structural design according to capacity, temperature, and vacuum degree requirements, draw drawings, and procure stainless steel plates, heating elements, and sealing parts.
- Plate cutting and bending forming: Stainless steel plates are cut on a shearing machine and formed on a bending machine; the inner liner and outer shell are processed separately, with dimensional accuracy controlled to the millimeter level.
- Full welding of inner cylinder and corner treatment: The inner cylinder is fully welded to ensure sealing; R50 stainless steel corner pieces are fully welded at right angles, with smooth transitions at seams to eliminate cleaning dead corners.
- Polishing of inner surface to low roughness: The inner cylinder and corner welds are ground and polished section by section, achieving a roughness of Ra ≤ 0.4 μm to prevent material adhesion and residue.
- Insulation filling and outer cover plate welding: Aluminum silicate fiber cotton is filled between the inner liner and outer shell, and the outer cover plate is welded to enclose the insulation layer, reducing equipment heat loss.
- Bracket fabrication and layered pressure testing: Stainless steel tubes are cut and drilled, then mirror-polished; they are assembled and welded layer by layer and acid-pickled; the whole assembly is hydrostatically tested at 1.0–1.2 MPa and held for 2 hours.
- Finishing of door body and sealing parts: The door flange is planed and then a mushroom-shaped seal groove is machined; the door frame and chamber body are welded together and then planed as a whole to ensure tight sealing of the door body.
- Integration of piping and vacuum interfaces: Seamless steel pipes are used for connecting pipes; the vacuum cover is rolled and welded after opening with a 50% open area; T-shaped female threaded connectors are provided at interfaces for easy disassembly and cleaning.
- Electrical control cabinet assembly and wiring: Install PLC, temperature control modules, vacuum gauges, and touch screens; complete electrical wiring; and write logic programs for temperature control and vacuum pumping.
- Chamber air-tightness and tube bundle hydrostatic tests: The chamber is subjected to an air-tightness test at 0.196 MPa gauge pressure, and the heating tube bundle is subjected to a hydrostatic test at 1.0 MPa, held for 30 minutes with no leakage.
- No-load trial operation and vacuum retention inspection: Start the vacuum pump and heating system for no-load operation, and record the baseline of ultimate vacuum degree, temperature uniformity, and pressure rise rate.
- Surface treatment and finished product packaging and warehousing: The outer surface is brushed or powder-coated, cleaned, and covered with protective film; it is packed in wooden cases with pressure test and trial operation records attached.
Steps of Square-Type Vacuum Drying / Vacuum Tray Dryer Equipment
