Essay on Garbage (Dry Refuse) Disposal system

Vegetables, meat and food left over’s unit is installed at the outlet of the kitchen sink. The cutting action of its blade enables the unit to pulverize what is thrown in it, which is then flushed into the drainage system aided by a little water obtained by opening the tap. The final waste is liquid in form and does not clog the pipe.

The unit is however not suitable for hard materials like bones, bottles, cans, etc. It is also not advisable to throw plastic bags or fibres which do not get pulverised.

For cooking utensils pre-soaking is required before scouring with a hard brush and abrasive and then washing and rinsing, and drying for reuse. Glassware should follow the same sequence as for crockery, except that it can be emptied of remaining liquids and placed straight into the water with detergents.

The uses of dishwashing machines for large volumes of washing have reduced the amount of handling and costs through reduced labour and lesser breakages. With power equipment, greater attention is now necessary on the storage of washed pans, dishes and glass wares rather than detergents, hot water and staff.

Cooking utensils gets resanitised when placed on the source of heat for cook­ing, but proper storage of tableware is important to prevent recombination. A bacterial count of less than 100 is acceptable, but when it exceeds this figure, it means the washing, handling and storage needs attention.

Thus, at every stage of the production cycle, occasional checks are necessary to maintain standards of hygiene and sanitation, and to ensure safe feeding to customers. The guidelines for efficient dishwashing are:

(a) All plate waste, leftover, and swill should be collected away from the dishwashing area, in covered bins, for final disposal before utensils or crockery is stacked for washing.

(b) All equipments should not be collected to be washed at the end of a service. Dishwashing should be a continuous process to avoid areas which can become sources of contamination.

(c) Free flowing hot water should be made available for this task.

(d) Knives and other sharp tools should be kept on the drain board for washing, and never thrown into the sink, where staff may not expect them and thereby cutting their hands while washing.

(e) Staff must be informed if a hot pan is placed on the drain board for washing.

(f) All cooking pans must be soaked immediately after use to loosen adher­ents and decrease washing effort.

(g) Staff responsible for dishwashing should be equipped with nonslip gloves with good grip for the job, to protect hands from strong detergents and the heat of the water, yet prevent breakages caused by slipping.

(h) Handling of washed utensils should be minimised. This can be done if they are allowed to drain and air dry in their storage racks, to be removed only when required for use.

(i) Dishwashing should never be rushed as these increases the health hazards for all-staff and customers. To ensure this does not happen during rush hours, there should be adequate provision for crockery, Cutlery and utensils.

Dishwashing Units:

The most suitable arrangement for dishwashing is to make provision for a row of three sinks, one each for pre-washing, washing and rinsing. Small food service establishments can have a double sink arrangement for dishwashing, in which the water is changed frequently, while larger ones may resort to three to five sinks, for hand washing of crockery or cutlery.

Washing by machine saves time and effort and increases safety because temperatures near boiling point can be used. Automatic dishwashing machines usually have adjustable washing cycles to suit the washing requirements for crockery, glass and stainless steel.

The amount of glassware and crockery required, however, increases to nearly 2-2 1/2times the seats in a food service. Rinsing cycles are also built in for items.

Dishwashing Area:

The dishwashing function is usually performed in a separate room or area that has to be well ventilated and illuminated. Acoustical tile and noise-absorbing materials are used to aid in lowering the high noise levels associated with this function.

The design of the dishwashing area is dependent upon the total volume of dinnerware to be washed and the time required accomplishing the washing. Some operation may prefer to carry a large dinnerware inventory in order to spread the washing over a long period of time. This usually occurs between the meal periods.

Others may decide to carry a minimum dinnerware inventory and must therefore wash the items as soon as they are soiled so they can be returned to service imme­diately.

Dishwashers are:

The major item of equipment for dinner ware washing is generally classified by the number of tanks:-

(i) A single-tank dishwasher is the smallest-capacity machine and is used for limited facilities. Counter-service operation frequently uses single-tank dishwashers that are either bench-mounted or placed under counter or work tables. Most single-tank dishwashers have only a wash-and-rinse cycle.

(ii) Two-tank dishwashers are used for greater loads and are available in rack or reckless models. The usually have a power wash cycle, a power rinse cycle, and have a pre-wash cycle instead. The discharge sections are designed to allow sufficient drying of dinnerware before it is handled.

(iii) Larger three-tank dishwashers have power pre-wash, wash, and rinse sections, and are designed for a final rinse cycle as well.

Dishwasher capacity is stated in terms of numbers of pieces of dinnerware that can be washed per hour. Some manufacturers also have recommendations of size based on the number of meals to be served per meal period.

For example, a single- tank dishwasher will be suitable for washing dinnerware from 50 to 600 meals per meal period. Two-tank machines are capable of handling dinnerware from 1500 to 2000 meals per period. Three-tank dishwashers are usually rated for 2500 meals per period.

These recommendations are guides, and the actual capacity required for a particular operation will depend on the number of each type of dinnerware to wash and the time allowed for washing.

Dishwashing machines:

For hygienic washing up the generally recogniscd requirements are a good supply of hot water at a temperature of 60 C for general cleansing followed by a sterilising rinse at a temperature of 82″C for at least 1 minute. Alternatively low-temperature equipment is available which sterilises by means of a chemical, sodium hypo chloride (bleach). Dishwashing m/c are.

1. Spray types in which the dishes are placed in racks which slide into the machines where they are subjected to a spray of hot detergent water at 48-60°C (118-140″F) from above and below.

The racks move on to the next section where they are rinsed by a fresh hot shower at 82°C (180″F). At this temperature they are sterilised, and on passing out into the air they dry off quickly.

2. Brush-type machines use revolving brushes for the scrubbing of each article in hot detergent water; the articles are then rinsed and sterilised in another compartment.

3. Agitator water machines in which baskets of dishes are immersed in deep tanks and the cleaning is performed by the mechanical agitation of the hot detergent water. The loaded baskets are then given a sterilising rinse in another compartment.

The dishwasher, sometimes known as the China Clipper, comes in various types and sizes. Dishwashers are normally classified as (i) UNDER COUNTER, (ii) DOOR-TYPE (iii) CONVEYOR-TYPE OR (iv) FLIGHT-TYPE (reckless); there is also a circular conveyor-type dishwasher sold under trade names such as (v) FAST RACK, Flight-A-Round, and Circa-U-Magic.

The purpose of the dish­washer, regardless of its size and design, is to provide a wash cycle, a rinse cycle, and final rinse. The final rinse sanitized the items, and the water temperature at this stage should be a minimum of 180° F.

The machine’s water tanks are provided with either electric, gas, or steam heat to maintain the temperature of the water. Dish­washers are equipped with spray arms located at top and bottom in the tanks; these spray arms are removable for cleaning.

(I) Under Counter Models:

As the name implies, are built in under the counter top with a drop-down front door. These dishwashers require the incoming water to be at the same temperatures as other machines do. The dishes, glasses, and so on are loaded in a rack-just as in door-type and conveyor-type machines.

The cycle on this type of dishwasher is three-and-a-half to four minutes, as com­pared to the thirty to forty-five minutes required in a domestic unit. Under counter models are also available as free-standing machines.

(ii) Door-Type:

Machines have a single tank in which one rack of dishes at a time is washed and finally rinsed.

(iii) Conveyor-Type:

Dishwashers are available with one or two tanks. The racks of dishes enter the machine at one end and are automatically pulled through the machine, where they are washed, rinsed, and final rinsed before exit­ing at the other end.

This type of dishwasher is provided with a third compartment located at the entrance end that serves as prewash unit for removing food waste from the dishes before they enter the wash section.

(iv) The Flight-Type Dishwasher:

Moves the dishes through the machine on a conveyor. The dishes are placed in a vertical position between pegs. They then go through a prewash tank, a wash compartment, a rinse compartment, and the final rinse.

(v) The Fast Rack -Type:

System is a continuous operation where dishes either in racks or in a vertical position on the conveyor are pulled through the dishwasher, which can be a single-or double-tank machine. The items will con­tinue to run through the dishwasher until the operator removes them from the operation of the dishwasher.

The prewash tank should be provided with water at a temperature from 120″to 140″ F, the wash tank with water at a temperature from 140° to 160° F, and the final rinse with water at a temperature from 180° to 195° F.

(vi) In the early 1970s, a new type of system was introduced to the dishwashing field. The machine is referred to as a Low-Temperature Or Energy-Sav­ing Dishwasher.

It is available in under counter, door-type and single-tank conveyor models. This type of dishwasher is designed to use water heated to a minimum of 120″ F, and it eliminates the need for a booster heater. The final rise makes use of a chemical sanitizing agent-normally chlorine.

Maintenance of Dishwashers:

Consult the manufacturer’s literature before you start servicing the dishwasher in order to take into account differences in construction and in methods of replac­ing various parts.

1. Daily cleaning of the dishwasher by the operating personnel can prevent many service problems.

2. Deliming program where hard water conditions prevail. A heavy lime buildup can otherwise cause many unnecessary service problems. A deliming schedule should be arranged with the supplier of the dishwasher detergent.

3. If the tanks are not holding water, check the tank drain to see if it is seating properly.

4. Check for foreign material in drain, and remove all such material.

5. Inspect the O-ring; if it is damaged, replace the ring.

6. If the solenoid valve fails to operate properly, check the incoming elec­trical service and the water or steam line pressure against the ratings specified on the nameplate of the valve. If the solenoid valve does not make a metallic click, this indicates loss of power supply.

7. Check for loose or blown fuses, a grounded coil, and broken lead-wires or connections.

To replace the valve from the line. Simply turn off the electric power and the water or steam supply, and then perform the following steps:-

1. Disconnect the electrical leads at the solenoid valve.

2. Remove the pal nut the spring washer from the top of the valve.

3. Lift the defective solenoid coil from the bonnet.

4. Place the new coil on the valve bonnet, and secure it with the spring washer and the pal nut.

5. Reconnect the electrical leads.

You should rarely (if ever) have to replace the solenoid valve. At times, how­ever, you may have to replace parts other than the coil. The parts that most often need to be replaced are usually available in a repair kit. The following steps should be performed to replace interior parts:

1. Turn off the electrical power and the water or steam supply, disconnect the electrical leads, unfasten the valve from the water or steam line, and remove the solenoid valve.

2. Loosen the bonnet nut, and remove the valve body (which consists of the plunger assembly, the piston spring, the piston body, the seat washer, and the seat washer nut) from the bonnet.

3. Remove the plunger assembly, the piston spring, and the piston body e from the solenoid valve.

4. Secure the seat washer to the piston body with the seat washer nut.

5. Install the two split rings in the groove of the piston body.

6. Install the piston assembly in the valve body, positioning the piston in the body seat.

7. With the piston spring on the plunger assembly, position the plunger on the piston and connect the valve body to the bonnet, locating the top of the plunger in the solenoid valve; secure this with the bonnet nut.

8. Reinstall the entire solenoid valve in the steam or water line, and recon­nect the electrical leads.

When starting the dishwasher, check the rotation of the pump. The tank should always have water in it before you turn the pump on. Consult the manufacturer’s literature for information on the proper rotation of the pump, if the direction is not marked on the pump itself.

Leakage at the pump is normally caused by worn gaskets or seals. These should be replaced. Leaks may occur in the following places; the pump seal; the drain-case-to-pump-case seal/gasket; the pump-outlet to vertical up rosier and the pump case-to-pump-out O-ring.

Before replacing or performing any maintenance on the pump or pump motor, make sure that the main power to the dishwasher is turned off and that all water has been drained from the dishwasher. Consult the manufacturer’s literature for infor­mation on how to remove the pump and the pump motor.

If the vacuum breaker leaks, the vacuum breaker disk should be replaced. If the seat is worn, the entire vacuum breaker should be replaced.

On conveyor-type dishwashers:

The final rinse cycle is normally controlled by a micro switch that is electrically connected to the solenoid valve in the final rinse piping. The dish rack presses the final rinse activator against the spring- loaded plunger of the micro switch.

The plunger thereupon closes the micro switch, energizing the solenoid valve and allowing water to enter the final rinse piping. After the dish rack releases the final rinse activator, the micro switch opens and the solenoid valve is reenergized, shutting off the final rinse water.

If the final rinse action is not satisfactory, check to see if the activator is tripping the micro switch soon enough. If-it becomes necessary to adjust or replace the activator or micro switch, consult the manufacturer’s literature for the proper procedure to fol­low.

The manufacturer’s literature should also be consulted for information on the operation, adjustment, and replacement of the final rinse controls, since these differ from one manufacturer to another.

Steam-operated dishwashers are equipped with steam injectors or steam coils. The heating system includes a manual shout off valve, a line strainer, a steam solenoid valve, and a steam trap in the return line (when steam coils are installed).

The primary maintenance task with this type of heating system consists of keep­ing the controls clean and free of foreign material. The recommended steam pres­sure is 1.4 kg/cm² minimum and 3.15 kg cm², maximum.

On dishwashers with steam injectors, excessive noise can occur if the pressure exceeds 3.15 kg/cm². If high pressure poses a problem, a pressure regulator should be installed to cut the pressure down.

Dishwashers designed to use gas heat normally include a main burner, a pilot and thermocouple, a combination control (100 percent safety shutoff, solenoid gas valve, pilot regulator, and on natural gas only-pressure regulator), a shutoff valve, a low-water cutoff, and a thermostat.

The main burner should never be allowed to operate unless there is water in the tank, to avoid damage to the tank. To check to see if the low-water cutoff system is operating, open the access door and remove the scrap trays. With water in the tank and the main burner on, care­fully depress the low-water cutoff float to s -e if the safety control functions.

If it is operating properly, the control should shut off the burners. If the control does not shut off the burners, consult the manufacturer’s literature for information on the operation, adjustment, and replacement of parts for the gas heating system.

Dishwashers provided with electric heat contain heating elements, a mag­netic contactor, a low-water cutoff system, and a thermostat. To check the opera­tion of the low-water cutoff system, follow the procedure indicated in the preced­ing paragraph.

Do not energize the elements by manually raising the low-water cutoff float as this can cause premature element failure. Consult the manufacturer’s literature for information on the operation, adjustment, and replacement of parts for the electric heating system.