MXPA00008222A - Portable combination hydro cooling and forced refrigerated air cooling unit - Google Patents

Abstract

A portable cooling trailer for cooling produce at the harvest site, where the produce may be cooled by either forced air refrigeration, where cooled air is drawn through the produce and recycled through a heat exchanger, or hydro cooling, where chilled water is sprayed onto the produce, recaptured and recycled through the heat exchanger

Description

PORTABLE COMBINATION OF AIR COOLING UNIT REFRIGERATED FORCED AND HYDRO-COOLING UNIT BACKGROUND OF THE INVENTION This invention relates, generally, to the field of transportable chilling units, which comprise a relatively large compartment for receiving agricultural products, such as fruits and vegetables, and resources for rapidly reducing the temperature of the products. products within the compartment, for subsequent transfer within delivery trailers. More particularly, the invention relates to units that incorporate the techniques of hydro-cooling, where the cooled water is directed on and through the products, and cooling by forced air cooling, where the air is cooled by a cooling expansion system and circulated through the products. When fruits and vegetables are harvested, the ripening and corruption process begins immediately. It is well known that cooling or cooling products retards maturation and reduces this deterioration, thus increasing shelf life and freshness. The faster the products cool down, the faster the harvest, the results are better. Since the harvest usually takes place during the months of hot weather, the products contain a large amount of field heat. Additionally, the products themselves create heat through respiration. The deterioration due to heat is directly related to the moisture loss of the product, which shortens the shelf life and reduces the quality of the product. The differential in the vapor pressure, between the cells of the product and the air that surrounds it, determines the regime of loss of humidity. The low temperature of the air and the high moisture content decrease the moisture loss of the product. For certain products, rapid cooling by hydro-cooling is preferred, for other types of products, cooling by chilled air is preferred, and for others, a combination of the two methods may be better. Alternatively, environmental or other site-specific conditions may dictate the preferred cooling method. Since it is more beneficial to cool the crop as soon as it is harvested, transportable cooling units have been developed to provide resources to achieve cooling at the harvest site itself, the provision of permanent cooling structures at the vast number of sites Harvesting has a prohibitive cost and is not optimally effective, since the construction of a permanent cooling structure in a generally centralized location requires that the products be first transported to the structure, with heat deterioration occurring during the transport period and wait. An approach in the cooling of the products immediately at the harvest site has been to improve the cooling efficiency of the refrigerated product delivery trailers themselves, ie the trailers used in transporting the crop from the field to the processing centers. distribution or process, such as the shortest time required to reach the desired temperature, once the delivery trailers are loaded. The problem with this approach is that a compromise must be maintained between the desire to decrease the weight and the space requirements of the cooling equipment, so that the container space and fuel efficiency are maximized, and the desire of the maximum efficiency of the cooling equipment, since the reduction of the time required to cool the products is directly related to the weight, size and type of equipment used. Thus, while advances have been made in improving the cooling efficiency of delivery trailers, the optimal approach has been aimed at providing specialized portable cooling units, with large and efficient cooling capacities, which can be carried out at the sites ÍiteijiÉt1 ~ tlnr - '* "" - ~ - ^ M * || É * < ft ^ - '. ~ - ~ »-.- * -. "• * -. * - iH-Mta * -» individual harvesting, where these portable cooling units are used to rapidly cool the products before loading them onto the delivery trailers or to cool the delivery trailers after the products have been shipped. The increased cooling capacity of large portable cooling units, which provide a relatively rapid reduction in temperature, which can not be obtained by the limited cooling units incorporated in the delivery trailers, has been charged. 10 There are several common methods used to cool products after harvest. The most common method is by the use of a recirculating refrigerant unit, circulating a refrigerant gas, such as Freon, through an expansion / compression cycle with the hot air, or external air from the environment or, preferably, the air inside the trailer being driven through the cooling coils to reduce the air temperature. The cooled air is then passed through the products by an air element forced, such as a fan. Another method is known as cryogenic cooling, where a reserve of supercooled gas, such as liquid nitrogen or carbon dioxide, is allowed to expand by its spraying into the trailer, causing the heat to be removed from the tanks. products. Yet another method is known as the hydro- cooling, where the cold water is sprayed on the products, from upper nozzles, the water is discharged or recycled, as shown in the patent of E.U.A., No. 3,961, 925 of Rhoad. It is known to supply several of the known cooling methods in a single portable cooling unit. For example, U.S. Patent No. 4,060,400 to Williams and U.S. Patent No. 4,936,100 to Leppa show a trailer having both a cryogenic cooling unit and a mechanical refrigeration cooling unit. U.S. Patent No. 4,406,131 to Weasel, Jr. teaches a trailer that uses both hydro-cooling and cryogenic cooling. U.S. Patent No. 3,604,217 to Spear shows a combination of hydro-cooling and vacuum cooling unit. A drawback in cryogenic systems, where the trailer is filled with a gas of nitrogen, carbon dioxide or other non-respirable gas, is that the units must be purged and the atmosphere replaced with the ambient air, before the personnel can enter to the trailer. In addition, cryogenic gases must be transported to remote harvest sites, since on-site sources are not available.

Therefore, an object of this invention is to provide a portable apparatus and method for rapid cooling of products at the harvest site, where the products are placed inside the portable cooling apparatus, cooled sufficiently and then transferred into the delivery trailers for the removal from the harvest site, where the cooling methodology involves the use of forced air cooling, hydro-cooling or both, and where the forced air cooling equipment involves passing air through a cascade of cold water inside a heat exchanger, with the cooled air then forced through the products and circulate again through the cascade of water, and further where the cooling unit can be used as a hydro-cooler , by importing additional water from a water source at the site, cooling the water in the water cascade, pumping the chilled water on the products, through of nozzles in the trailer's sky and recapture the water, in a capture tank, under the floor of the trailer, for its cycle again through the heat exchanger to re-cool.

COMPENDIUM OF THE INVENTION The invention is, in general, a portable combination of a hydro-cooling apparatus and a 6 cooling of forced refrigerated air, for cooling products or the like at the harvest site, before transport, comprising a general resource for the air or water cycle through the cooling medium and then into a cooling compartment, relatively large, through large quantities of products, placed inside the compartment, and then repeatedly return to the cooling medium to decrease, significantly and quickly, the temperature of the the products. The portable cooling unit is preferably constructed as a wheeled trailer, which can be pulled to the harvest site by a motorized tractor, in a known manner, where the cooling compartment comprises an accessible large enclosed area. for doors mounted on the rear or side and where a cooling means is provided on a separate part of the trailer. The cooling medium comprises a mechanical cooling system of the expansion / compression type, where a compressed refrigerant gas is passed in expansion coils. The water is driven from a holding sump and carried in cascade on the coils within a heat exchanger, and the expansion refrigerant gas expels the heat from the water. For the method of forced air cooling, the air is driven towards up through the cascade of chilled water, to remove heat from the air, and cold air is then forced into the cooling compartment by ceiling mounted cooling fans of the cooling compartment. This cooled air is carried through the products to remove the heat, and the heated air is then driven through a return air channel, adjacent to the cooling medium and cycled back through the water cascade. The process is then repeated until the desired reduction in the temperature of the products is reached. The refrigerant gas and the cascade water are also cycled repeatedly in a known manner. For the hydro-cooling method, additional water is loaded into a large capture tank below the interior floor of the cooling compartment. This water is pumped into the heat exchanger and forms a cascade on the cooling coils and cools, and this cooled water is then pumped through spray heads, mounted on the roof of the cooling compartment, where it flows through the products, to remove the heat and then discharge into the capture tank to cycle back over the cooling coils in the water sump. ^ 4 ^^^ "^ g &klttÁkM ^ M ^^ BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side of the cooling unit with the nearby side wall removed to expose the interior. Figure 2 is a top view of the cooling unit with the upper wall substantially removed and portions of the airflow control member removed to expose the interior. Figure 3 is a rear end view of the cooling unit, with the end wall and door removed to expose the interior.

DETAILED DESCRIPTION OF THE INVENTION With reference to the drawings, the invention will now be described in detail with respect to the best mode and the preferred embodiment. In general, the invention comprises a portable cooling unit, for reducing the temperature of articles placed within the unit, and, in particular, is designed to reduce the temperature of freshly harvested products, such as fruits or vegetables, in the Harvest site, before these products are loaded onto delivery items, such as trucks or trailers, APRA transport to distribution or process sites. Preferably, the cooling unit is constructed as an insulated trailer, with wheels, which can tágteys you will be moved by a truck tractor to different sites. In this embodiment, the cooling unit 100 comprises an upper wall 101, a bottom wall 102, side walls 103 an end or rear wall 104, a front wall 105 and an internal floor 108, which together define an enclosed area that it can be sealed, which is subdivided into a cooling compartment 109, an air handling compartment 110 and a cooling equipment compartment 111. Unit 100 of cooling is mounted on wheels 106 and stabilizing legs 107 are provided, which can be extended, for use when the unit 100 is operational. One or more doors 112, shown as a type of wrapping, mounted at the rear, with a spool 113 of door, are provided to allow access into the cooling compartment 109. The overall structure of the cooling unit 100 is similar to typical i-trailer constructions, in which the unit 100 is generally rectangular in configuration and size, for its transport along roads. The floor 108 of the cooling compartment 109 is constructed to be strong enough to support multiple pallets 201, loaded with product baskets 202, these baskets 202 have openings or slots, so that the air can go inside and through the baskets 202 and the products 10 ^ - £ ÉiÉ --- l --- áifa-tfi contained there. The pallets 201 are arranged within the cooling compartment 109 in two longitudinal rows, to define a central runner 203, which extends to the front of the cooling compartment 109, and these pallets 201 are loaded so that the baskets 202 are generally uniform along the top, and that they meet with other baskets 202 on the adjacent pallets 201, layer forming a side wall, generally continuous, on each side of the corridor central 203. A member 204, solid, flexible, air flow control, is placed above the baskets 202, which extend from the front of the cooling compartment 109 to the back of the platforms 201, and down to the 108th floor. In this way, the central corridor 203 is an enclosed area bounded by the inner wall 116 of the cooling compartment 109, the floor 108, the air flow control member 204 and the side walls formed by the baskets 202. The air driven within the central runner 203, therefore, it must pass to through the baskets 20. One or more liquid discharges 114 are located on the floor 108 and return air vents 116 are placed in the front of the floor 108, as shown, or in the lower section of the interior wall 116. A relatively large capture deposit 117 is located under the 108th floor, this capture deposit 117 receives 11 the water flowing through the drain 114. The capture tank 117 has doors, so water from an outside source can be introduced into and removed from the tank 117. A copper or sink 118 is supplied under the 5th floor 108, in front of the tank 117, part of the water sump 118 is placed below the air return vents 115 and part is below the air treatment compartment 110, to receive water from the water cascade. The water sink 118 also defines a path or camera for the flow of return air between the air vents 115 and the forced air cooling element 30. A compensating valve 119 is provided between the capture tank 117 and the water sump 118, so that equal water levels are maintained during the hydro-cooling process. The front compartment 111 of the cooling equipment, which may be enclosed, completely or partially, contains the mechanical cooling element 90, which comprises a standard set of equipment, necessary to achieve expansion and compression of a refrigerant gas, such as Freon, to perform mechanical refrigeration in a commonly known manner. Such equipment is well known in the art and comprises a power element, a compressor, an evaporator-condenser, a suction accumulator, coils of 12 ^ ¡^ ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡, M < , > É - * - - ^ «- ^^ to ^ - ^ .- * - ^ * - ^ *» - r-- - - - • * »~ A? ?? expansion, a control element and several other components, and those skilled in the art can easily build the necessary assembly, which preferably provides at least about 55 tons of refrigeration and more preferably about 110 tons of refrigeration. The expansion coils containing the refrigerant extend into the air treatment compartment 110 and into the heat exchanger 31, which includes part of the cooling element 30 of air and water. This heat exchanger 31 is of the water cascade type and is comprised of a high surface area with an average volume. Water driven from either the water sump 118 (for the cooling of air blown) or from a capture tank 117 (for hydro-cooling) by the pump element 32, passes over the coils and is cooled. The cooled water then cascades through the heat exchanger 31 and into the sink 118 of the water, from which it is cycled again onto the coils. Such devices are well known and produce chilled water at about 0.56 ° C and even less, if additives are provided that reduce the freezing point, such as salt or glycol. The cooling element 30 further comprises a large number of high volume static depression fans 33, positioned near the upper part of the inner wall 116 and communicating between the air handling compartment 110 and the cooling compartment 109. The fans 33 are used for forced air cooling and are located above the baskets 202 and above the heat exchanger 31, and pull air through the air vents 115 in the floor 108 of the cooling compartment 109, through of the air treatment compartment 110, and forced into the upper part of the cooling compartment 109. Because the flow control member 204 blocks the upper and rear part of the central runner 203, between the baskets 202, the air is forced through the exposed upper portions and out of the baskets 202, and then is driven from the baskets 202 through the side walls and inside the central runner 203. This air, which has been cooled in the heat exchanger 31, removes heat from the cooling compartment 109 and from the products themselves, thereby lowering their temperature. Due to the closed cycle, the unheated air within the central runner 203 is driven through the air return vents 115, through the chilled water cascade in the heat exchanger 31, where it is cooled again, and is forced back into the cooling compartment 109. This cycle is continued until the 14th -fe juutítm? jJU4ttt,? im? > . je. -i 3.¡ * i. - A. - desired temperature inside the cooling compartment 109. For hydrocooling, additional water must be present in the capture tank 117, since a much larger volume of water is required than that required for the water cascade in the forced air cooling method. This water will typically be delivered in the capture tank 117 at the harvest site to reduce the weight during transportation of the cooling unit 100. A compensating valve 119 is opened to equalize the water levels in the reservoir 117 and the water sump 118. The water is driven from the capture tank 117 by the pump 32 through suitable arrangements of conduits, or a second pump, not shown, is supplied. This second The pump may be necessary because a much higher flow rate is required for hydro-cooling (approximately 6056 liters per minute) than for air cooling (approximately 1703 liters per minute). Water is passed over the coils of coolant in the heat exchanger 31, but the fans are not activated so that no air is driven through the heat exchanger 31. In this way, the water that enters the water sink 118 is cooled to its maximum. The distribution conduits 34 are arranged along the interior of the upper wall 101 of 15 cooling compartment, which preferably extends longitudinally, adjacent or close to each side wall 103. A plurality of spray nozzles 35 are positioned along the conduits 34. A pump element 36 drives the cooled water from the sump 118 of the water and pumps it through the nozzles 35, where the cooled water falls on top of the baskets 202 and is filtered through these baskets 202 and onto the products, and then goes to the 108th floor. As with the cooled air, the cooled water absorbs heat from the cooling compartment 109 and the products, thus reducing the temperature. The warm water then passes through the drains 114 into the capture tank 117 or through the vents 115 into the water sump 118. The cycle is then repeated continuously until the desired temperature is reached within the cooling compartment 109. It will be understood that equivalents and substitutions for certain elements, indicated above, may be obvious to those skilled in the art, and that the true scope and definition of the invention, therefore, will be indicated in the following claims. 16 - f? t-rt- iftÉTT-t rr - .. ^. ^ .. ^ fe-. ^ f, fflf- || ---.- < --..-

Claims (8)

1. CLAIMS 1. A method for cooling agricultural products at the harvest site, this method includes the steps of: harvesting the products and placing them inside a portable cooling unit, this cooling unit has the ability to cool the products for a forced air cooling element or a hydro-cooling element; choose one of the two elements to cool the products and then cool the products using the chosen element; and remove the chilled products from the portable cooling unit.
2. 2. The method of claim 1, wherein the step of cooling the products by the forced air cooling element, comprises passing air through a cascade of water cooled in a heat exchanger, passing the air over and through the products for Remove residual heat from these products, and circulate the air again through the chilled water cascade, where the cycle is repeated until the products have cooled to the desired temperature.
3. 3. The method of claim 1, wherein the step of cooling the products by the hydro-cooling element, comprises importing water into the portable cooling unit, cooling this water in a cascade of chilled water, pumping the water on the products, through nozzles placed above the products, capture the water in a tank and cycle the water back through the chilled water cascade, where the cycle is repeated until the products have cooled to the desired temperature.
4. 4. The method of claim 2, wherein the step of cooling the products by the hydro-cooling element, comprises importing water into the portable cooling unit, cooling the water in a chilled water cascade, pumping the water onto the products to through nozzles, placed on top of the products, capture the water in a tank and cycle the water again through the chilled water cascade, where the stages are repeated until the products have cooled to the desired temperature.
5. 5. A portable cooling unit, to lower the temperature of agricultural products or other items, this cooling unit comprises a cooling compartment and a cooling element. 18 In order to reduce the temperature of the cooling compartment and the agricultural products or other articles, placed inside the cooling compartment, this cooling element comprises a mechanical expansion / compression refrigeration system, which has a compressed refrigerant gas. which passes inside the expansion coils, the water is driven from a sump and forms a cascade on the coils, inside a heat exchanger, a fan to force the air through the heat exchanger and into the cooling compartment and to cycle the air through the cooling compartment and the heat exchanger, a pump and distribution duct, to deliver the water inside the cooling compartment, a capture tank inside the cooling compartment, APRA receive the water and a pump to cycle the water again over the coils.
6. 6. The portable cooling unit of claim 5, wherein this cooling unit is an insulated trailer, having wheels.
7. 7. A portable cooling unit, to lower the temperature of agricultural products or other items, that cooling unit comprises a 19 cooling compartment and a cooling element, to decrease the temperature of the cooling compartment and the products or other articles, placed inside the cooling compartment, this cooling element comprises a mechanical cooling element, which includes a heat exchanger of Water cascade, a forced air cooling element, for delivering cooled air from the heat exchanger inside the cooling compartment 10 and back to the heat exchanger, and a hydro-cooling element, to deliver cooled water from the exchanger of heat inside the cooling compartment and again inside the heat exchanger.
8. 8. The portable cooling unit of claim 5, wherein said cooling unit is an insulated trailer, having wheels. twenty taüiii- "1 ^^ •" - * - - • - * - j- < * 'aaMi ^ Tí "" iiíÉítta **? fcMifcM * - ^? t? - • »-.» * * - *.! * - «*« •• «.-.