Document 10wbO6a340xxQ3Ke53poBBp2q

918 CHAPTER 62 1965 Guide And Data Book bottle cooled. The temperature differential between bottle bottles do not need to be refrigerated until a few hours before and refrigerant is held to a minimum, thereby assuring' rela-' they, are to be vended. This means that the refrigeration ca tively high suction-pressure operation and consequent im pacity does not need to be sufficient to cool a full load of provement in efficiency. : ^ ... .. bottles at one time, if toe air path can be directed over^only Dependable stock rotation is not assured in this type of cooler since a bottle can be removed from any section of the part of the load. Generally the bottles move through'thh refrigerated zone as they progress toward the vending'posi cooler at will. If the bottles are stacked horizontally, -it is ' tion. Operation of the fan during the off-eyeU of the re possible to arrange the loading so that the fresh warm bottles frigeration system will aid in keeping the bottles at approxi are located at the bottom, and the cooled bottles are at the mately the same temperature. Also, defrosting action is faster top of the cooler. This is desirable because it assures that cold ; with air blowing over the evaporator. bottles'are available for the next customer. ` ' . Because it takes several hours to cool a warm bottle with a While horizontal stacking of the bottles results in maximum conventional refrigerating system, it is'desirable to provide bottle capacity H also impedes the air flow. The cold air is space in the vendor for precoding some bottles for the next generally blown over the top layer of bottles in the cooler and reload. These precooled bottles are then loaded so that they then proceeds down through the lower layers of bottles to the are dispensed ahead of any warm bottles. bottom of the cooler, where a rack is located to provides space' Some manufacturers prefer to 'provide extra space in'the for .tte return .air. In this manner adequate air'.distribution vending mechanism and arrange a means of stopping opera-, throughout the entire cooler is obtained. In the larger sizes tion before these extra bottles are vended. In this way,' the of coolers, it is difficult to cool the bottles in toe extreme precooled bottles are already in place and the work of trans^ ranters (even in the top layer) to the same temperature as exists,in toe center of the cooler. ferring the bottles is eliminate! when reloading. By this method, rotation of stock is assured and bottles are not left ,`tPresent construction provides'easy access tothe refrigera in the precooling space long enough to become stale! tion unit for replacing and servicing. Compact'design simpli fies'replacement of the complete unit.' DESIGN CONSIDERATIONS Vertical Forced-Air Type . These vendors are manufactured in capacities of 40 to 350 bqttlcs.`Tbe size of vendor for a particular sales location is influenced mainly by toe rate of bottle sales and toe time intervals between reloading. v- The bottles may be arranged in toe vendor in many different ways depending on the type of vending-mechanism.-The bottles may be stacked compactly in columns, or -placed' in individual compartments. Still another arrangement consists of inclined shelves on which the bottles roll by gravity to one side where they are removed through !a harrow*door."v -V*' O.; -- In order to. provide a stable bottle temperature, it has been found necessary to provide forced-air circulation. - ...., j. The-evaporator is usually of toe finhedrtube.type, com- pactly,<wound-or formed,-with a fan. to circulate,air.through the evaporator and over the bottles. . An important consideration of the air circulation is to direct it from toe evaporator to toe bottles which are in position to be-vended. This not only helps to keep these bottles .colder butenables them to be cooled quickly when the vendor is, first loaded with warm bottles. Another consideration is that the NSULATtON The purpose of a vendor is to furnish cold bottled beverages to the customers. How well the vendor does this depends largely on how well the vendor is matched to the job. For ex ample, a vendor which would hokl a full day's sale and which' could be reloaded at closing time each day would need little excess refrigerating capacity over losses through heat leakage. Such a vendor would have many hours during the night in which to cool the bottle load. On the other hand, a vendor which would normally be reloaded several times a day, would require the necessary cooling capacity to cool toe bottle load and also compensate for the heat leakage during the day. - Rates of Anticipated Sales When cooling, up to 50 Btu of heat must be removed per.6 oz bottle, depending on the specific heat of the beverage, weight of glass bottle, and temperature of bottles before they are placed in the vendor. The rate of sales will therefore be an important consideration in toe refrigeration capacity of the vendor. If sales are fairly steady, a high degree of zone cooling would be desirable. However, heavy peak demands would require more refrigeration capacity and cooling of a greater percentage of the bottles to assure that the demand could be supplied. Vendors are usually designed for these peaks. A knowledge of the anticipated sales per hour and per day is needed to determine the machine bottle capacity as well as its refrigeration capacity. The vendor must refrigerate bottles as rapidly as they are sold, except that peak sales may be taken care of by a reserve of cold bottles in toe vendor. Together with the anticipated sales rate, the anticipated reloading schedule will finally determine the bottle capacity of the machine. Reloading once a .day is considered normal but reloading twice a day is common. Where a considerable distance must be traveled to reload, it is often practicable.to provide a vendor of sufficient size to require reloading only, once or twice a week. The extra investment in initial cost may be more than saved in decreased time,ami travel required to keep a smaller machine in service. ... Temperatures The expected range of ambient conditions is an important factor in design. Many vendors are placed outdoors in direct Bottled Beverage Coolers and Refrigerated Vending Madiines 919 sunlight where the cabinet exterior surface may reach 160 F. Some vendors may have sufficient capacity to refrigerate, the load in the northern part of toe United States but will not be satisfactory in the wanner climates. Aside from adequate cooling capacity, bottle temperature must be controlled within acceptable limits under the expected widely varying ambient temperatures. Controls which hold the bottle tem peratures within 2 or 3 F deg at one ambient condition do not always work as well under other ambient conditions. For jngt&nrft, the constant cut-in control, which has been widely used because of its dependable defrosting action, has the in- herent characteristic of allowing the bottle temperature to drop as toe ambient rises, because of the increase in compres sor running time. The product must often be cooled from above 100 F (where the product is stored in the sun or delivered from open truck) to 32 F or slightly below. It is desirable to keep bottles as cold as possible without freezing. A product temperature above 40 F is considered unsatisfactory. One of the most important functions of the control system is to insure adequate defrosting of the evaporator. Several methods used to accomplish this function are: (1) toe hot-gas ~ defrost system, (2) a timing device that operates heaters or insures an adequate off period every 24 hr or less, and (3) the use of a gas- or liquid-charged control with a fixed cut-in temperature above freezing. In the latter method the control bulbis placedon theevaporator. In this' manner, n<Hng a cut-in temperature of approximately 35 F, complete, defrosting is insured during each off period of the unit. This necessitates the use of a wide differential control since the cut-off tempera ture must be in the range of 12 to 25 F, depending upon indiT vidual unit design, in order to provide cold bottles under all ambient conditions. Vendors with this control are usually de signed for indoor use. When vendors are used outdoors in locations where temper atures are apt to drop to below 40 F, a control with a_crossambient feature (liquid charged bellows) must be used, or the entire control must be located inside the cooling compart ment. (See Chapter 45.) This is necessary to assure that the actuating bulb is actually functioning to operate the control and give toe desired product temperature. If the unit has a capillary tube, it may be desirable to use a thermostatic de-; vice to stop toe condenser fan .when the ambient temperature is low. This will control the condensing temperature and. will provide adequate pressures for the proper functioning of the capillary tube at low ambient temperatures, | If it is known that a vendor is to be.used in such a way that the entire load of bottles will be used in a few minutes, toe best arrangement would be to cool all the bottles as a unit since there would not be time to do much additional cooling before toe bottles are used. One method of assuring adequate cooling with toe minimum compressor rise is to utilize an area in the refrigeration com partment, which is in relatively poor heat-transfer relation ship to the evaporator and to the bottles in the vending mechanism. Bottles placed in this area will gradually cool while the bottles in the vending area are being vended. If the heat transfer characteristics are balanced, these bottles will be cold by toe time the bottles in the vending section are Us^L Warm bottles are then placed in this precooling area. One ad vantage of this arrangement is that warm bottles can-be loaded into the vendor without raising the temperature of the other bottles. The main disadvantage is that extra work is involved in moving the bottles from the precooling area. Also, .because of the extra labor involved, the attendant will often load directly into the vending mechanism, leaving'the bottles in the precooling area where they will get stale!'For these reasons, the trend has been to incorporate as much of-the available space as possible into toe vending mechanism itself. The total capacity of a machine should-be slightly more than toe expected peak sales between reloadings, plus^ ca pacity to last until reloaded bottles are cooled. .The cabinet must be large enough to accommodate the vending mechanism with its bottles and the evaporator and fan. Due to the particular construction of some vending mechanisms, there may be spaces in the vendor which would be wasted if they were not used for precooling bottles. Bottle Size and Shape .Many different sizes and shapes of bottles are used for beverages,-with each brand usually having a distinctive rite and shape. Bottle dimensions are critical in some vending mechanisms. Information regarding the bottle length and major diameter, weights of the bottle, liquid, and cap, as well as the specific heat of toe filled bottle, and the freezing point of the beverage may be obtained from the bottling plant. The wide variety of surface irregularities have not caused detectable differences in cooling rates in bottle coolers tested. It is probable that toe irregular surfaces promote turbulence with resulting increased heat transfer. Freezing Point of Beverage The freezing point of beverages while still under carbona- tion pressure in the'bottle varies considerably. While some beverages with low carbonation and low sugar will form heavy ice crystals near 31 F, others will remain fluid in the capped bottle at temperatures as low as 21 F. Also, sample bottles of toe same beverage have been found to vary over a wide range with some bottles showing large amounts of ice crystals at 27 F, while others showed no ice crystals when sustained at 21F, even after being shaken and jarred. When the cap (or crown) is removed from a bottled bever age, toe freezing point changes radically. Release of toe car bon dioxide pressure allows, the beverage to assume a con sistent freezing point which for many beverages is approxi mately 29 F. If the liquid is raider than this when the cap is removed, there is a rapidly growing formation of ice crystals as the temperature immediately jumps to the normal freezing point. This may be desirable in some warmer climate areas of the United States,-where customers wont to have ice crystals or flake ice form in their bottle when toe cap is re-' moved. To accomplish this, the bottle must be vended at a temperature within a narrow range from 1 to 4 F deg below the freezing point of toe beverage at atmospheric pressure. If the temperature of the bottle is lowered further, the ice form ing will cause the liquid and ice to push out of the bottle with waste and spillage. ' The specific heat of the majority of carbonated beverages is very close to that of water. For determining cooling rates, test bottles may be filled with water to the usual beverage level without undue errors in performance values. To prevent freezing in the bottles it is usual to add enough ethylene glycol antifreeze to the water to lower the freezing' point to approximately 20 F. Air Circulation Circulating air, used almost universally at present for cool- ing bottles,' may be varied in quantities and velocity for par ticular applications. While a pound of air will carry only approximately 0.2 Btu for each degree change in temperatore as the air moves through the cabinet, the quantity of air will be determined by the velocity needed around the bottles. Vending principles will determine bottle positions in machines