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Case & Guide
Everything You Need to Know About Jacketed Kettles in One Post
What Will You Learn from This Post?
In canned food processing, central kitchens for catering, jam production plants, fruit processing factories, as well as deep processing lines for fruits, vegetables, meat, and fish, how can you efficiently blanch raw materials and prepare consistently flavored soups, sauces, or jams? The answer usually lies in the jacketed kettle, also known as the double-layer kettle. Though the equipment features a simple structure, failing to distinguish between fixed and tiltable types, or neglecting condensate drainage and acid-salt corrosion issues, will not only slow down cooking and boiling efficiency but also pose potential safety hazards. By reading this article, you will learn about the structural advantages of jacketed kettles, standardized operating procedures, as well as anti-corrosion and maintenance tips that can double the service life of the equipment.
Structures, Types, and Key Functions
1. Structure:
A jacketed kettle gets its name from its common hemispherical, double-layered shell structure. The two layers are welded together, forming a jacket heating chamber. Depending on the operation method, it is mainly divided into two structural categories:
| Fixed Jacketed Kettle | The steam inlet pipe is installed on the shell at a 60° angle to the center line of the kettle body. Discharging relies entirely on gravity drainage through the bottom pipe or using a pump. Therefore, it is ideal for preparing high-fluidity liquid materials like soups and sauces. When the volume exceeds 500L or is used for thick materials, it is usually equipped with a paddle or anchor agitator running at 10-20 r/min. |
| Tilting Jacketed Kettle | Hollow journals are welded on both sides of the kettle body and supported on the frame bearings, where the steam pipe extends into the jacket. Through a worm gear mechanism, operators can turn the handwheel to tilt the kettle at any angle between 0 to 90°, making it easy to pour out highly viscous materials or residues. |
2. Core Functions
● Seasoning & Sauce Cooking: The core equipment for preparing savory sauces and broths in canned food processing.
● Blanching & Pre-cooking: Utilizing the high thermal efficiency of the jacket to quickly blanch and cook raw fruits, vegetables, meats, or seafood to lock in freshness.
Standard Operating Procedure (Including Condensate Management)
1. Pre-start InspectionCheck whether the pressure gauge and safety valve are in normal condition. Make sure the exhaust outlet is unobstructed, so that the safety valve can automatically exhaust steam once the pressure exceeds the allowable limit (e.g., the upper limit of design pressure). |
2. Start Mixing & Steam SupplyTurn on the stirrer first if processing viscous materials. Then slowly open the steam inlet valve to feed steam. Inspect the sealing condition of the stuffing box connecting the journal and steam pipeline to avoid steam leakage caused by abrasion during tilting and rotation. |
3. Drain Condensate During ProductionIf obvious water hammer noise is heard inside the jacket, it indicates accumulated condensate, which will seriously reduce cooking efficiency. Open the cock on the non-condensable gas outlet to drain condensate in a timely manner, or ensure the steam trap works properly for continuous automatic drainage. |
4. Discharging & Post-use Residual Liquid DrainageDischarge materials through the bottom valve (for fixed type) or tilt the kettle body by turning the handwheel (for tiltable type). After each shift, completely drain all condensate inside the jacket to prepare for the next operation. |
Maintenance & Anti-Corrosion Secrets
⚠️ Critical Warning: The jacketed kettle is a special pressure vessel. Although its spherical inner tank is fabricated by stainless steel welding, the weld seams are vulnerable to corrosion from long-term exposure to high-concentration saline, acidic solutions and similar materials.
To extend the service life of the equipment and guarantee production safety, the following maintenance specifications must be strictly followed:
| Frequency | Maintenance Tasks |
| After Every Shift | Immediate Cleaning: Wash the inner wall and welds thoroughly immediately after production. Never leave high-salt or high-acid materials in the kettle long-term to prevent intergranular corrosion. |
| Daily | Transmission Lubrication: Add lubricating oil to the worm gear mechanism and bearing grease cups on both sides to maintain smooth tilting and reduce wear. |
| Periodically | Pressure Testing & Weld Inspection: As a pressure vessel, periodic pressure tests are mandatory. If the welded joints are found worn thin or leaking, stop using it immediately for maintenance. |
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