Sterilization kettle Also known as a sterilization pot or sterilizer, the sterilization kettle is widely used in industries such as food processing, manufacturing, and pharmaceuticals.

　　The sterilization kettle consists of a vessel, a lid, an opening mechanism, locking wedges, an interlock device, rails, a sterilization basket, steam nozzles, and other components. The lid is equipped with an inflatable silicone rubber heat‑resistant seal, ensuring reliable sealing and long service life.

　　What are the operating instructions for the sterilization kettle?

　　Typically, canned-food manufacturers employ this type of horizontal retort when using atmospheric-pressure cooking for heat sterilization; the retort can be pressurized with compressed air to achieve semi‑pressure sterilization. If cooling is required inside the retort, a pump should be used to circulate water through spray nozzles at the top of the vessel (or through a water‑circulation system).

　　During sterilization in a retort, heating raises the temperature inside the can, causing the internal pressure to exceed the external pressure (the pressure within the retort). Therefore, to prevent excessive pressure buildup in glass jars—leading to lid popping and deformation—the cans are subjected to counter‑pressure at both ends of the tinplate container. This is especially important for meat canned products that require high sterilization temperatures.

　　Pressure‑inhibiting sterilization involves applying compressed air to the retort to prevent can rupture and lid popping. Since compressed air is a poor conductor of heat, the saturated steam itself also maintains a certain pressure. Therefore, during the temperature‑raising phase of sterilization, no compressed air is introduced; only during the holding period, once the target sterilization temperature is reached, is compressed air injected into the retort to increase the internal pressure by 0.5 to 0.8 atmospheres. In particular, after sterilization, as the temperature drops, steam supply is shut off and cooling water pressure is applied to the spray pipes. As the retort temperature decreases, the steam condenses, reducing the internal pressure, and the pressure of the injected compressed air compensates for this reduction.

　　During the sterilization process in the retort, it is essential to vent air at the outset, release steam, and ensure adequate steam circulation. Additionally, air should be purged every 15 to 20 minutes to enhance heat transfer. In short, all sterilization parameters must comply with the specified requirements. The retort’s sterilization temperature, pressure, duration, and operating procedures are precisely defined by the canning product’s sterilization process.

　　What are the selection criteria for sterilization kettles?

　　1. Selection should primarily be based on temperature‑control accuracy and uniformity of heat distribution. If the product demands extremely tight temperature tolerances—especially for export‑grade items—and consistent heat distribution, a fully computerized retort is recommended whenever possible. Computer‑assisted semi‑automatic retorts offer computer‑based temperature and pressure control, yet their price is only about one‑third that of fully computerized models. For most applications, an electrically powered semi‑automatic retort is a suitable choice. Manual sterilization kettles, by contrast, present greater challenges: temperature and pressure are regulated manually, making it difficult to maintain consistent product appearance, and they tend to result in higher rates of can (or pouch) breakage and product fragmentation.

　　2. If the product is packaged in a gaseous form or has stringent appearance requirements, a fully automatic or semi-automatic computer-controlled sterilization retort should be selected.

　　3. If the product is packaged in glass bottles or tinplate containers, both the heating and cooling rates must be precisely controlled; therefore, a double‑stage retort cannot be used.

　　4. To conserve energy, a dual sterilization pot can be selected. Sterilization kettle Its key features are: the upper tank serves as a hot-water reservoir, while the lower tank functions as a processing vessel. Reusing the hot water from the upper tank can significantly reduce steam consumption, making it well suited for food-processing enterprises with a daily output exceeding 10 tons.