Vertical Counter‑Pressure Retort LS‑35L/50L/75L/100L | Dual‑Mode Sterilization for Food Packaging Aseptic Testing
Product Introduction
Reliable dual‑mode counter‑pressure sterilizer tailored for food packaging quality control & lab aseptic evaluation. The vertical counter‑pressure retort is a medium‑small‑size mechanically program‑controlled counter‑pressure sterilization equipment. The sterilizer adopts electric heating mode. Water is directly injected into the sterilizing chamber and heated to generate high‑pressure steam required for sterilization to disinfect articles. After sterilization is completed, external compressed air and water pressure are applied for rapid cooling within 3 minutes, cooling internal articles down to 30‑40℃.
Equipped with program control, it supports two operation modes: boiling disinfection and pressure sterilization with rapid cooling. Boiling temperature can be set ≤100℃. The rapid‑cooling pressure sterilization temperature is pre‑selectable within 101℃‑135℃. It is integrated with heater overload protection and buzzer alarm upon sterilization completion. Featuring simple operation and high safety reliability. This unit is suitable for disinfection and sterilization of food packaging, utensils and instruments. It is an ideal device especially for aseptic tests in food research institutions.
Working Principle
Dual‑sterilization logic enables boiling disinfection & high‑pressure counter‑pressure sterilization, simulating real‑world thermal processing conditions for flexible packaging samples. This equipment is designed with two disinfection & sterilization principles to deliver dual‑function performance for customers. The heater directly heats water to produce pressurized steam. The pressurized steam acts on microorganisms on samples and destroys their structures to realize sterilization.
When rapid‑cooling sterilization program starts, 6 liters of tap water is first injected into the chamber. After around 25‑minute heating process, it enters sterilization holding stage with sterilization duration of 35‑40 minutes. When sterilization finishes, 0.24 MPa compressed air and tap‑water pressure are manually fed into the chamber, then half‑open the drain valve to discharge water and implement counter‑pressure cooling for flexible packages and other specimens. Rapid cooling lasts for 3 minutes. Manually cut‑off compressed air and tap‑water supply, and internal articles can be cooled down to 30‑40℃.
Core Advantages
- Dual‑mode operation: boiling disinfection & counter‑pressure pressure sterilization
- Ultra‑fast 3‑minute counter‑pressure cooling to avoid flexible pouch deformation
- Heater overload protection & buzzer alarm when sterilization cycle completes
- Multiple chamber volume options:35L‑50L‑75L‑100L for different test throughput
- Mechanical program control, easy operation for laboratory staff
Technical Parameters
| Item | Specifications |
|---|---|
| Max Working Pressure | 0.22 MPa (30 Psi) |
| Max Working Temperature | 135℃ |
| Sterilization Temperature Selection | 101‑135℃ |
| Boiling Temperature Selection | ≤100℃ |
| Timer Range | 1‑60 min |
| Effective Chamber Volume | 35L, 50L, 75L, 100L |
| Power / Power Supply | 2.5 KW / AC220V, 50Hz; 3 KW / AC220V, 50Hz; 4.5 KW / AC220V, 50Hz |
| Overall Dimension | 570×550×970 mm(35L); 590×590×1110 mm(50L); 650×630×1150 mm(75L); 680×650×1220 mm(100L) |
| Gross / Net Weight | 56/42 kg(35L); 68/50 kg(50L); 90/70 kg(75L); 105/85 kg(100L) |
Application Scenarios
Widely adopted in food R&D laboratories, packaging manufacturers and quality inspection institutes for sterilization and thermal‑resistance assessment of flexible food packaging materials.
- Disinfection & sterilization for food flexible packaging, containers and lab utensils
- Aseptic test and thermal resistance evaluation for food packaging samples
- Sterilization for laboratory instruments and small‑batch food test specimens
GBPI Packaging Test Equipment
Official Website: www.gbpitester.com

info@gbtest.cn



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