As an Engineman, you may be required to work with galley or scullery equipment. This equipment includes such items as vegetable peeling machines, garbage grinders, steam-jacketed kettles, and dishwashers. In the follow-ing sections, we will discuss some characteristics of steam kettles and dishwashing machines.

Steam-Jacketed Kettles

Steam-jacketed kettles come in various sizes from 5 gallons to 80 gallons. The kettles are made of corrosion-resisting steel. They are constructed to operate at a maximum steam pressure of 45 psi. A relief valve, installed in the steam line leading to the kettles, is set to lift at 45 psi. Other steam-operated cooking equipment items include steamers and steam tables. Steamers use steam at a pressure of 5 to 7 psi; steam tables use steam at a pressure of 40 psi or less. Any maintenance you may perform on these units will normally be limited to the associated steam supply and drain lines and valves.

Dishwashing Machines

Dishwashing machines used in the Navy are classified as one-tank, two-tank, or three-tank machines. The three-tank machine is a fully automatic, continuous-racking machine which scrapes, brushes, and provides two rinses. It is used at large activities.

SINGLE TANK.-Single-tank machines (fig. 18-9) are used in small ships where larger models are not feasible.

To control the bacteria to a satisfactory minimum in single-tank machines, the temperature of the washwater in the tank must

Figure 18-9.-Typical semiautomatic single-tank dishwashing machine.

be between 140 and 160F. Consequently, a ther-mostat in the machine prevents operation when the temperature of the water falls below 140F. Water temperatures higher than 160F result in less efficient removal of certain foods. The washing time in the automatic machines is 40 seconds. For rinsing, hot water is sprayed on the dishes at a temperature between 180 and 195F. To conserve fresh water, the rinse time interval is usually limited to 10 seconds. When water supply is not a problem, a rinse of 20 seconds is recommended.

Wash and rinse sprays are controlled separately by automatic, self-opening and closing valves in the automatic machine. The automatic machines provide a 40-second wash and a 10-second rinse.

DOUBLE TANK.-Double-tank machines (fig. 18-10) are available in several capacities and are used when more than 150 persons are to be served at one meal. These machines have separate wash and rinse tanks. They also have a final rinse of hot water which is sprayed on the dishes from an external source.

This spray is actuated by the racks as they pass through the machines. The spray automatically stops when the rinse cycle is completed. The final rinse is controlled by an adjustable automatic steam mixing valve which maintains the temperature between 180 and 195F. Double-tank machines are also equipped with a thermo-statically operated switch in the rinse tank which prevents operation of the machine if the temperature of the rinse water falls below 180F. The racks pass through the machine automatically on conveyor chains. The double-tank dishwashing machine should be timed so that the utensils are exposed to the machine sprays for not less than 40 seconds (20-second wash, 20-second rinse).