Water Spray Retort

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Spray Water Retort System

Spray water retort systems may be either static or rotary batch, (end-over-end) systems, depending upon the make or model. These retorts are designed to process a wide variety of packages including: glass, metal, rigid plastic and flexible pouches. They are normally operated with a compressed air over-pressure to maintain container integrity during thermal processing.

Spray water retorts differ from the cascading water retort (in which the water falls or is sprayed over the top of the containers) in that the water is sprayed over the containers, from several different angles to atomize the air used for over-pressure.

A small amount of water in the bottom of the retort is heated by the addition of steam through two steam spreaders located in the bottom of the retort. The water is pumped through the system by a high capacity pump. The water sprays circulate the steam/air mixture in the retort. The containers are cooled after processing by the addition of cooling water to the retort.

Instrumentation is normally located in the shell of the retort. The MIG thermometer and the temperature recorder probe are located to sense the temperature of the steam/air/water mixture in the retort.

The areas of concern with spray water retort systems are similar to those for the water cascade type retort system.

1. The process must be designed to provide for adequate temperature distribution. The cold spot in the retort must be determined. This may vary with container type and arrangement in the retort.

Temperature distribution studies should be performed on each retort model, each product produced, each container type used, each crate or racking configuration used and on each individual retort installation.

2. Care should be taken to determine the location of the control and recording instruments. The recording sensing probe must be located where it will provide an accurate record of the thermal process. The MIG thermometer must be installed where it will indicate the true thermal processing temperature in the retort.

3. Water flow may not normally be directly controlled as a critical factor. A water flow measuring device is recommended to provide a more accurate measurement of actual water flow in the system. Water flow in the system must be the same as that used during temperature distribution studies in the retort.

4. The holes in the water distribution sprays may become plugged through clogging with product, and through the buildup of mineral deposits. There should be a program in place for routine maintenance and cleaning of the water sprays and water filter screens if present. During the inspection of these systems the water distribution sprays should be examined to determine if the holes are plugged or have been reduced by mineral scale buildup.

5. The records maintained by the firm must document that operating steps set-up to provide uniform temperature distribution in the retort during processing are being met

When spray water retort systems are encountered it is important to determine if the retort system is being operated under the same conditions used during temperature distribution testing