CA1054814A - Apparatus for refrigerating materials - Google Patents
Apparatus for refrigerating materialsInfo
- Publication number
- CA1054814A CA1054814A CA297,569A CA297569A CA1054814A CA 1054814 A CA1054814 A CA 1054814A CA 297569 A CA297569 A CA 297569A CA 1054814 A CA1054814 A CA 1054814A
- Authority
- CA
- Canada
- Prior art keywords
- drum
- header
- refrigerating
- gas
- chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
APPARATUS FOR REFRIGERATING MATERIALS
Abstract A refrigerating system for use in the continuous cryogenic treatment of materials has a rotatable drum that can receive and discharge such material. The drum has an interior configuration that advances the material longitudinally within the drum upon its rotation. The material is refrigerated while it is within the drum. The system includes a reciprocating feeder device for shaking material placed therein into the drum at a preselected controlled rate of introduction. This feeder device comprises an intake header juxtaposed to the material receiving end of the drum so that the drum is free to rotate with respect thereto. The intake header forms a chamber communicating with the interior of the drum and is divided into a plurality of chambers separated from one another by a partition having an opening therein with a chute passing through such opening. The opening has a door biased normally closed for automatically allowing material to pass through the partition and for automatically closing, once material has passed therethrough.
Abstract A refrigerating system for use in the continuous cryogenic treatment of materials has a rotatable drum that can receive and discharge such material. The drum has an interior configuration that advances the material longitudinally within the drum upon its rotation. The material is refrigerated while it is within the drum. The system includes a reciprocating feeder device for shaking material placed therein into the drum at a preselected controlled rate of introduction. This feeder device comprises an intake header juxtaposed to the material receiving end of the drum so that the drum is free to rotate with respect thereto. The intake header forms a chamber communicating with the interior of the drum and is divided into a plurality of chambers separated from one another by a partition having an opening therein with a chute passing through such opening. The opening has a door biased normally closed for automatically allowing material to pass through the partition and for automatically closing, once material has passed therethrough.
Description
- lQS4t~14 This invention relates geneFally to continuous cryogenic treatment of materials. More particularly, the lnvention relates to an apparatus for continuously feeding material, such as scrap, through a freezing zone to render it brlttle so that, thereafter, it can be crushed or impacted and separated according to the various types of material of which it is composed.
In the prior art, it is known to subject material, such as insulated wire, to a low temperature gas, such as nitrogen, in a liquid atomized state, so that the insulation becomes brittle and can be cracked off of the metallic wire, thereby separating the wire from the insulation. See, for example, Morita et al, United States Patent 3,647,149, issued March 7, 1972.
One disadvantage of the prior art devices, such as that shown in the referenced patent, wherein a conveyor belt is used ln the freezing zone, i3 that it is difficult to lubricate the moving parts of the apparatus within the extremely cold environment.
Also, there can be a frost build~up within the device and the accumulation of fine particles or other undesirable material.
Other problems that have arisen in prior art devices involve the distribution and agitation of the gas within the freezing chamber and, in particular, involve attempts to get maximum exposure of the product to the cooled gas and maximum utilization of the cooling effect of the gas. The present application is a division of Canadian application Serial No.
201,110 filed May 29, 1974 and various aspects of the apparatus disclosed therein are claimed in such parent application and in the other divisional applications Serial Nos.
and ~ ~ 57d filed simultaneously herewith.
~0 According to the present invention there is provided a refrigerating means, comprising: a. a rotatable drum having l~S4814 means to receive and to discharge material; said drum having an interior configuration which further comprises transport means for advancing the material longitudinally within said drum upon rotation of the drum; b. rotation means engaging said drum for rotating said drum; c. an intake header means through which material may be introduced into said drum, juxtaposed to the material receiving end of said drum so that said drum is free to rotate with respect thereto, said intake header means forming a chamber communicating with the interior of said drum; d. refrigeration means within said drum to refrigerate material while it is within said drum; said refrigeration means further comprising a low temperature fluid introduced within said drum; and e. recirculation means to recirculate said fluid from said chamber of said intake header means, to and through the end of said drum from which material is discharged.
In drawings which illustrate embodiments of the invention:
Figure 1 is a side view of an apparatus partially broken away and shown in section with alternate positions shown in phantom lines and certain portions shown schematically;
Figure 2 is an enlarged section taken as indicated by the lines and arrows 2-2 in Figure 1, which has been foreshortened and partially broken away;
Figure 3 is a greatly enlarged section taken as indicated by the lines and arrows 3-3 in Figure 2;
Figure 4 is an enlarged end view taken as indicated by the lines and arrows 4-4 in Figure l;
Figure 5 is a foreshortened side view of an alternate embodiment;
Figure 6 is a section taken as indicated by the lines and arrows 6-6 in Figure 5, with portions of the apparatus shown in phantom lines; and Figure 7 is an enlarged section of a portion of the device shown in Figure 1.
Although specific forms of the invention have been selected for illustration in the drawings, and the following description is drawn in specific terms for the purpose of ~.o54~14 describing hesc forms of the invention, this description is not intended to limit the scope of the invention which is defined in the appended claims.
In Figure 1 a drum, designated generally 10, comprises a cylindrical shell 12 made of a suitable material for with-8tanding extremely cold temperatures, such as 304 stainless steel or other similar cryogenic material. The interior of the drum is provided with a means for transporting material through the drum upon rotation of the drum. In the preferred embodimsnt shown, the interior configuration of the drum comprises a flat spiral blade 14 disposed in a helix welded along the inner surface of the drum. The blade extends radially inwardly from the wall of the drum a distance of approximately ona-tenth of the diameter of the drum.
The drum is supported for rotation on a plurality of rings 18 which provide a force transmitting, insulating means. The rings are of a unique construction in that they comprise two T-shaped members insulated from one another by a spacer made of plastic or other suitable insulating and force-transmitting material. A cross-section of a typical ring is shown in Figure 3. The outer T-shaped portion 20 is a metallic ring while the inner T-shaped portion is made up of a plurality of L-shaped pieces 22 and 24 formed into an annular ring. The stems of the T-shaped portions are opposed and are joined by four brackets 26 L-shaped in cross-section and a plastic spacer 30. Referring to Figures 2 and 3, each of the brackets 26 are welded to their respective stems of the T-shaped portions. Bolts 28 firmly clamp the plastic spacer 30 between the brackets 26.
The outside of the cylindér is covered with an insulat~ng material 16, which extends outwardly from the shell 12 past thc inller free end of the stem 20 and engaglng and covering the inncr portion of the r~ngs, but not beyond the outer face of the ring 20, Thus, the insulation does not inter~ere with the rollers 40 which have flanges 42 embracing the cross portion Oe the T-shaped ring 20, so that the ring tracks in and rolls on the roller 40. The rollers 40 are driven by means of sprockets 44 mounted on common shafts with .the rollers and interconnected by means of a chain 46. The Qprocket 47 is mounted on a shaft 48 driven by a pulley belt drlve means, designated generally 49, connected to a source of motive power 50, Figure 1. This electric motor 50 is a variable speed motor, so that the speed at which the drum 10 rotates on the driven rollers 40 can be ad~usted. Ad~usting the speed of rotation ad~usts the travel of material through the drum and thus regulates the exposure of the material to cold gas. ~lternatlve means could be provided for rotating the drum on the rings, such as hydraulic motors direc.tly driving the rollers 40.
Material enters the drum 10 by means of the input chute 60. This chute passes through a box-like entrance header, designated generally 62, at the upstream end, designated generally 64, of the drum 10. The upstream end 64 of the drum has an annular face plate 66 fixedly mounted thereto. Over-lapping the shell 12 is a cylindrical reinforcing shell 68 retained by an annular flange 70. Additional insulation is provided at 71. The walls of the header 62 are insulated as shown at 72. Between the insulation 71 and the insulation on the outer wall of the header 62, there is a heat tape 65. This tape can be heated by electricity remotely controlled to prevent frost build-up in the space shown and thereby prevent wearing of the insulation. At the point at which the chute 60 enters thc hcader ~)2 there i~s a ~ree swinging plate 74 forming a door wl~ich automat~al~y open.~ and closes as ~shown by the phantom an~l ful] ~ine positions respectively in Figure 1, when material comes d~wn the chute and enters the header on its way toward the drum 10. An additional free swinging door is provided by the insulated plate 76 mounted in the transverse partition 78 which completely divides thc box-like header into two compartments. These doors serve a useful function in connection with certain exhaust fans which will now be more fully described.
A stack 80 is provided communicating through the top of the header 62 with the upstream compartment 82. Within the stack 80 there is mounted a discharge fan 84 driven by any suitable motive means 85. The purpose of this discharge fan is to draw off air coming in with the material down the chute and also to draw off used nitrogen gas which may escape when the door 76 is opened. A control damper 87 is provided on the tischarge side of the fan 84.
In the preferred construction shown in Figure 5, the chute 60 is replaced by an alternate forced feeding means, such as a mechanical feeder 160, whlch reciprocates as shown by the arrows. The feeder is shown basically in a schematic form comprising a trough 162 mounted on arms 164 and driven in a reciprocating motion by means of a motor and crank arm, designated generally 166. This loosely shakes the incoming material into the rotating drum. The mechanism is not described in further detail herein since such feeders are known in the art. Indeed, a vibrating feeder could also be used as an alternative feeding means. It should be noted that the stack will continue to have a fan and a control damper for the same purposes as previously described.
~05D.~14 Whilc many kinds of materia].s can be processed by the apparatus, it has particular applicability to scrap metal which is composed of various components of material, such as ferrous and nonferrous metals which cannot be cleanly separated by mechanical means. By freezing the scrap material, it is pos8ible to shatter it ln a crusher or impactor and then separate out particular materials magnetically, or by other suitable means. In Figure l we have shown schematically a crusher 92 and a magnetic conveyor separator 94. ~hese devices are not shown in greater detail, since they are well known in the art.
The first stage in the separation process is the freezing unit, and we provide a pre-cooling chamber and a cooling chamber within our freezing unit 10. Liquid nitrogen is introduced into the freezing portion of the chamber (which i8 downstream when viewed in the direction of travel of the material through the chamber), through a common header 100 and a plurality of nozzles 102. As the nozzles spray the nitrogen into the chamber, it immediately vaporizes to low temperature gas and comes into intimate contact with the moving scrap material. As the drum rotates, the helical blade transports or advances the material down the drum. The inner surface of the shell 12 is continually moving with respect to the material, so that this surface is re-exposed to the cold gas intermittently and then comes in contact with the under surfaces of the material. This also has the effect of wiping the surface of the drum, thereby removing frost. This contact may be enhanced where flights or vanes are used, rather than a helix, by virtue of the churning action caused by the tumbling of the material as it proceeds down the inner surface of the drum. However, in this embodiment the helical -` ~0548~4 blade 14 is p~eferable, since the continuity of the blade presents a conÇiguration whlch is not susceptible to having lrregular pieces of material hang-up on lt. The header lO0 is supported on a cable 104, which is fixedly connected at one end to and within the heàder 62 and is fixedly connected at the other end to any convenient structure, such as at 106.
A tension device 108 is provlded to ad~ust the tension in the cable depending on the weight of the header 100. A
plurality of rings llO are connected to the header and disposed about the cable to support the header on the cable.
The liquid nitrogen, as it enters the chamber, is at a temperature of approximately -320F. In order to maximize the effectiveness of the nitrogen contact with the material, a flow ls provided by withdrawing some of the nitrogen gas from the upstream end of the drum and pumping lt back through a conduit 112 and a nozzle 114 into the downstream end of the drum 10. The nitrogen gas is heavier than air and for the most part lays in the bottom of the drum, which is mounted horizontally.
The internal transport means tend to make the gas flow out the discharge end. The reverse flow condition tends to inhibit this loss. It is difficult to maintain a closed fluid flow system with so many openings at the entrance and discharge ends, and, therefore, it is necessary to pump gas in at the discharge end to maintain the flow. When the door 76 is closed, the compartment 84 essentially communicates only through the port 86 in the end plate 66 within the cavity 89 formed within the shell 12. Used nitrogen gas is drawn out through this port 86 and down through the conduit 88 by means of the recirculating fan 90 which runs constantly as the device is operating. In the processing of scrap iron, for example, this recirculation of gas is at a temperature of about -150F once the unit reaches its continllous operatlng condition.
In the preferred embodiment shown in Figures S and 6, the nozzle 114 is replaced by an e~ector 214 mounted on the discharge end of the conduit 112. The lntake end of the ln~ector is provided with a control damper 216. In this embodlment, the ~lscharge header 218 embraces the dlscharge end of the rotating drum 10 to form a chamber for mounting the e~ector 214, as clearly illustrated in the figures. The bottom of the header 218 has a plurality of trap doors 220 which are rotatably mounted to swing between the closed positlon shown in full llnes and the open position shown in phantom llnes. The doors are spring biased or counterweighted by any suitable means (not 8hown) to return to their closed positlon when not acted upon by materlal being discharged from the drum 10. Protective means in the form of angle lrons and the like (as shown at 400; 401) are provlded mounted above the hinges to prevent ~amming of the hinge by material exiting from the unit. The doors open into a chute 222, which has a second pair of similarly mounted doors 224, which function in a similar fashion as shown by the solid and phantom lines. The chute 222 opens into the crusher 92. The e~ector improves the operation of the system by recirculating a portion of the nitrogen which would otherwise be discharged. This portion of the nitrogen is drawn into the ejector from the discharge header 218 as shown by the arrows in Figure 6 and is induced to flow from the discharge end of the drum toward the intake or upstream end of the drum.
The flow pattern provided by the recirculating system provides a pre-cooling chamber in the upstream portion of the drum 10 between the port 86 and that nozzle which is positioned at the upstream end of the header 100. In this pre-cooling chamber, the nitrogen gas which has lo~t much of its cooling power by virture of contact with the material in the drum in tlle downstream freezing portion thereof, is expo2~ed t0 the incoming material to reduce its temperature before it enters the freezing chamber, thereby increasing the effectlveness of the system in the freezing portion of the drum.
Since more nitrogen is constantly being introduced through the nozzles 102, there is a build-up of nitrogen gas such that the excess must, at times, be withdrawn. This is done in the recirculation cycle by means of the discharge conduit 116 connected to a valve mechanism (shown schematically at 117) which can be operated in response to an automatic flow indicator 118.
The input of nitrogen, the withdrawal of used nitrogen, and the speed of the rotation of the dru~ are all regulated in accordance wlth the actual effect on the particular items of material being processed. Thus, these can and must be adjusted depending on the thickness of the material and other factors which may be encountered in dealing with the particular material. In the case of scrap, the end result is to render some of the scrap components brittle and fragile by sub~ecting it to the low temperature refrigerant gas while conveying it ln the rotating drum, so that by the time the scrap is discharged through the insulated free swinging door 119 down the chute 120, Figure 1, into the crusher 92, it is ready for fragment-ation by impaction or crushing. To this end, thermocouples are provided as at 300, 30l, 302, 303, 304 and 305 to monitor temperature and for use in ad~usting the controls.
It will be observed from what has been described that in operation this device automatically takes care of frost build-up within the drum by virtue of the wlping action - lOS4~14 of the matcria~ nn thc w~lls of the drum, The lce whlcll is removed is then tr~nsported out of the drum with the material.
This wiping action also prevents particle build-up. Further-more, since there is no mechanism having moving parts within the freezing zone, there can be no freeze~up of the material transporting means.
It will slso be observed that by re-introducing a portion of the nitrogen gas at the downstream end of the drum, there is a thorough mixing and intimate contact between the refrigerant gas and the material. This contact is enhanced by the constant motion of the material within the drum.
It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature o this lnvention may be made by those skilled in the art within the principle and scope of the invention as expressed ln the following clalms. Por example, the same process and apparatus can be employed for cooling other materials, such as scrap rubber, food products, plastics, organic material, metallics, and the like.
In the prior art, it is known to subject material, such as insulated wire, to a low temperature gas, such as nitrogen, in a liquid atomized state, so that the insulation becomes brittle and can be cracked off of the metallic wire, thereby separating the wire from the insulation. See, for example, Morita et al, United States Patent 3,647,149, issued March 7, 1972.
One disadvantage of the prior art devices, such as that shown in the referenced patent, wherein a conveyor belt is used ln the freezing zone, i3 that it is difficult to lubricate the moving parts of the apparatus within the extremely cold environment.
Also, there can be a frost build~up within the device and the accumulation of fine particles or other undesirable material.
Other problems that have arisen in prior art devices involve the distribution and agitation of the gas within the freezing chamber and, in particular, involve attempts to get maximum exposure of the product to the cooled gas and maximum utilization of the cooling effect of the gas. The present application is a division of Canadian application Serial No.
201,110 filed May 29, 1974 and various aspects of the apparatus disclosed therein are claimed in such parent application and in the other divisional applications Serial Nos.
and ~ ~ 57d filed simultaneously herewith.
~0 According to the present invention there is provided a refrigerating means, comprising: a. a rotatable drum having l~S4814 means to receive and to discharge material; said drum having an interior configuration which further comprises transport means for advancing the material longitudinally within said drum upon rotation of the drum; b. rotation means engaging said drum for rotating said drum; c. an intake header means through which material may be introduced into said drum, juxtaposed to the material receiving end of said drum so that said drum is free to rotate with respect thereto, said intake header means forming a chamber communicating with the interior of said drum; d. refrigeration means within said drum to refrigerate material while it is within said drum; said refrigeration means further comprising a low temperature fluid introduced within said drum; and e. recirculation means to recirculate said fluid from said chamber of said intake header means, to and through the end of said drum from which material is discharged.
In drawings which illustrate embodiments of the invention:
Figure 1 is a side view of an apparatus partially broken away and shown in section with alternate positions shown in phantom lines and certain portions shown schematically;
Figure 2 is an enlarged section taken as indicated by the lines and arrows 2-2 in Figure 1, which has been foreshortened and partially broken away;
Figure 3 is a greatly enlarged section taken as indicated by the lines and arrows 3-3 in Figure 2;
Figure 4 is an enlarged end view taken as indicated by the lines and arrows 4-4 in Figure l;
Figure 5 is a foreshortened side view of an alternate embodiment;
Figure 6 is a section taken as indicated by the lines and arrows 6-6 in Figure 5, with portions of the apparatus shown in phantom lines; and Figure 7 is an enlarged section of a portion of the device shown in Figure 1.
Although specific forms of the invention have been selected for illustration in the drawings, and the following description is drawn in specific terms for the purpose of ~.o54~14 describing hesc forms of the invention, this description is not intended to limit the scope of the invention which is defined in the appended claims.
In Figure 1 a drum, designated generally 10, comprises a cylindrical shell 12 made of a suitable material for with-8tanding extremely cold temperatures, such as 304 stainless steel or other similar cryogenic material. The interior of the drum is provided with a means for transporting material through the drum upon rotation of the drum. In the preferred embodimsnt shown, the interior configuration of the drum comprises a flat spiral blade 14 disposed in a helix welded along the inner surface of the drum. The blade extends radially inwardly from the wall of the drum a distance of approximately ona-tenth of the diameter of the drum.
The drum is supported for rotation on a plurality of rings 18 which provide a force transmitting, insulating means. The rings are of a unique construction in that they comprise two T-shaped members insulated from one another by a spacer made of plastic or other suitable insulating and force-transmitting material. A cross-section of a typical ring is shown in Figure 3. The outer T-shaped portion 20 is a metallic ring while the inner T-shaped portion is made up of a plurality of L-shaped pieces 22 and 24 formed into an annular ring. The stems of the T-shaped portions are opposed and are joined by four brackets 26 L-shaped in cross-section and a plastic spacer 30. Referring to Figures 2 and 3, each of the brackets 26 are welded to their respective stems of the T-shaped portions. Bolts 28 firmly clamp the plastic spacer 30 between the brackets 26.
The outside of the cylindér is covered with an insulat~ng material 16, which extends outwardly from the shell 12 past thc inller free end of the stem 20 and engaglng and covering the inncr portion of the r~ngs, but not beyond the outer face of the ring 20, Thus, the insulation does not inter~ere with the rollers 40 which have flanges 42 embracing the cross portion Oe the T-shaped ring 20, so that the ring tracks in and rolls on the roller 40. The rollers 40 are driven by means of sprockets 44 mounted on common shafts with .the rollers and interconnected by means of a chain 46. The Qprocket 47 is mounted on a shaft 48 driven by a pulley belt drlve means, designated generally 49, connected to a source of motive power 50, Figure 1. This electric motor 50 is a variable speed motor, so that the speed at which the drum 10 rotates on the driven rollers 40 can be ad~usted. Ad~usting the speed of rotation ad~usts the travel of material through the drum and thus regulates the exposure of the material to cold gas. ~lternatlve means could be provided for rotating the drum on the rings, such as hydraulic motors direc.tly driving the rollers 40.
Material enters the drum 10 by means of the input chute 60. This chute passes through a box-like entrance header, designated generally 62, at the upstream end, designated generally 64, of the drum 10. The upstream end 64 of the drum has an annular face plate 66 fixedly mounted thereto. Over-lapping the shell 12 is a cylindrical reinforcing shell 68 retained by an annular flange 70. Additional insulation is provided at 71. The walls of the header 62 are insulated as shown at 72. Between the insulation 71 and the insulation on the outer wall of the header 62, there is a heat tape 65. This tape can be heated by electricity remotely controlled to prevent frost build-up in the space shown and thereby prevent wearing of the insulation. At the point at which the chute 60 enters thc hcader ~)2 there i~s a ~ree swinging plate 74 forming a door wl~ich automat~al~y open.~ and closes as ~shown by the phantom an~l ful] ~ine positions respectively in Figure 1, when material comes d~wn the chute and enters the header on its way toward the drum 10. An additional free swinging door is provided by the insulated plate 76 mounted in the transverse partition 78 which completely divides thc box-like header into two compartments. These doors serve a useful function in connection with certain exhaust fans which will now be more fully described.
A stack 80 is provided communicating through the top of the header 62 with the upstream compartment 82. Within the stack 80 there is mounted a discharge fan 84 driven by any suitable motive means 85. The purpose of this discharge fan is to draw off air coming in with the material down the chute and also to draw off used nitrogen gas which may escape when the door 76 is opened. A control damper 87 is provided on the tischarge side of the fan 84.
In the preferred construction shown in Figure 5, the chute 60 is replaced by an alternate forced feeding means, such as a mechanical feeder 160, whlch reciprocates as shown by the arrows. The feeder is shown basically in a schematic form comprising a trough 162 mounted on arms 164 and driven in a reciprocating motion by means of a motor and crank arm, designated generally 166. This loosely shakes the incoming material into the rotating drum. The mechanism is not described in further detail herein since such feeders are known in the art. Indeed, a vibrating feeder could also be used as an alternative feeding means. It should be noted that the stack will continue to have a fan and a control damper for the same purposes as previously described.
~05D.~14 Whilc many kinds of materia].s can be processed by the apparatus, it has particular applicability to scrap metal which is composed of various components of material, such as ferrous and nonferrous metals which cannot be cleanly separated by mechanical means. By freezing the scrap material, it is pos8ible to shatter it ln a crusher or impactor and then separate out particular materials magnetically, or by other suitable means. In Figure l we have shown schematically a crusher 92 and a magnetic conveyor separator 94. ~hese devices are not shown in greater detail, since they are well known in the art.
The first stage in the separation process is the freezing unit, and we provide a pre-cooling chamber and a cooling chamber within our freezing unit 10. Liquid nitrogen is introduced into the freezing portion of the chamber (which i8 downstream when viewed in the direction of travel of the material through the chamber), through a common header 100 and a plurality of nozzles 102. As the nozzles spray the nitrogen into the chamber, it immediately vaporizes to low temperature gas and comes into intimate contact with the moving scrap material. As the drum rotates, the helical blade transports or advances the material down the drum. The inner surface of the shell 12 is continually moving with respect to the material, so that this surface is re-exposed to the cold gas intermittently and then comes in contact with the under surfaces of the material. This also has the effect of wiping the surface of the drum, thereby removing frost. This contact may be enhanced where flights or vanes are used, rather than a helix, by virtue of the churning action caused by the tumbling of the material as it proceeds down the inner surface of the drum. However, in this embodiment the helical -` ~0548~4 blade 14 is p~eferable, since the continuity of the blade presents a conÇiguration whlch is not susceptible to having lrregular pieces of material hang-up on lt. The header lO0 is supported on a cable 104, which is fixedly connected at one end to and within the heàder 62 and is fixedly connected at the other end to any convenient structure, such as at 106.
A tension device 108 is provlded to ad~ust the tension in the cable depending on the weight of the header 100. A
plurality of rings llO are connected to the header and disposed about the cable to support the header on the cable.
The liquid nitrogen, as it enters the chamber, is at a temperature of approximately -320F. In order to maximize the effectiveness of the nitrogen contact with the material, a flow ls provided by withdrawing some of the nitrogen gas from the upstream end of the drum and pumping lt back through a conduit 112 and a nozzle 114 into the downstream end of the drum 10. The nitrogen gas is heavier than air and for the most part lays in the bottom of the drum, which is mounted horizontally.
The internal transport means tend to make the gas flow out the discharge end. The reverse flow condition tends to inhibit this loss. It is difficult to maintain a closed fluid flow system with so many openings at the entrance and discharge ends, and, therefore, it is necessary to pump gas in at the discharge end to maintain the flow. When the door 76 is closed, the compartment 84 essentially communicates only through the port 86 in the end plate 66 within the cavity 89 formed within the shell 12. Used nitrogen gas is drawn out through this port 86 and down through the conduit 88 by means of the recirculating fan 90 which runs constantly as the device is operating. In the processing of scrap iron, for example, this recirculation of gas is at a temperature of about -150F once the unit reaches its continllous operatlng condition.
In the preferred embodiment shown in Figures S and 6, the nozzle 114 is replaced by an e~ector 214 mounted on the discharge end of the conduit 112. The lntake end of the ln~ector is provided with a control damper 216. In this embodlment, the ~lscharge header 218 embraces the dlscharge end of the rotating drum 10 to form a chamber for mounting the e~ector 214, as clearly illustrated in the figures. The bottom of the header 218 has a plurality of trap doors 220 which are rotatably mounted to swing between the closed positlon shown in full llnes and the open position shown in phantom llnes. The doors are spring biased or counterweighted by any suitable means (not 8hown) to return to their closed positlon when not acted upon by materlal being discharged from the drum 10. Protective means in the form of angle lrons and the like (as shown at 400; 401) are provlded mounted above the hinges to prevent ~amming of the hinge by material exiting from the unit. The doors open into a chute 222, which has a second pair of similarly mounted doors 224, which function in a similar fashion as shown by the solid and phantom lines. The chute 222 opens into the crusher 92. The e~ector improves the operation of the system by recirculating a portion of the nitrogen which would otherwise be discharged. This portion of the nitrogen is drawn into the ejector from the discharge header 218 as shown by the arrows in Figure 6 and is induced to flow from the discharge end of the drum toward the intake or upstream end of the drum.
The flow pattern provided by the recirculating system provides a pre-cooling chamber in the upstream portion of the drum 10 between the port 86 and that nozzle which is positioned at the upstream end of the header 100. In this pre-cooling chamber, the nitrogen gas which has lo~t much of its cooling power by virture of contact with the material in the drum in tlle downstream freezing portion thereof, is expo2~ed t0 the incoming material to reduce its temperature before it enters the freezing chamber, thereby increasing the effectlveness of the system in the freezing portion of the drum.
Since more nitrogen is constantly being introduced through the nozzles 102, there is a build-up of nitrogen gas such that the excess must, at times, be withdrawn. This is done in the recirculation cycle by means of the discharge conduit 116 connected to a valve mechanism (shown schematically at 117) which can be operated in response to an automatic flow indicator 118.
The input of nitrogen, the withdrawal of used nitrogen, and the speed of the rotation of the dru~ are all regulated in accordance wlth the actual effect on the particular items of material being processed. Thus, these can and must be adjusted depending on the thickness of the material and other factors which may be encountered in dealing with the particular material. In the case of scrap, the end result is to render some of the scrap components brittle and fragile by sub~ecting it to the low temperature refrigerant gas while conveying it ln the rotating drum, so that by the time the scrap is discharged through the insulated free swinging door 119 down the chute 120, Figure 1, into the crusher 92, it is ready for fragment-ation by impaction or crushing. To this end, thermocouples are provided as at 300, 30l, 302, 303, 304 and 305 to monitor temperature and for use in ad~usting the controls.
It will be observed from what has been described that in operation this device automatically takes care of frost build-up within the drum by virtue of the wlping action - lOS4~14 of the matcria~ nn thc w~lls of the drum, The lce whlcll is removed is then tr~nsported out of the drum with the material.
This wiping action also prevents particle build-up. Further-more, since there is no mechanism having moving parts within the freezing zone, there can be no freeze~up of the material transporting means.
It will slso be observed that by re-introducing a portion of the nitrogen gas at the downstream end of the drum, there is a thorough mixing and intimate contact between the refrigerant gas and the material. This contact is enhanced by the constant motion of the material within the drum.
It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature o this lnvention may be made by those skilled in the art within the principle and scope of the invention as expressed ln the following clalms. Por example, the same process and apparatus can be employed for cooling other materials, such as scrap rubber, food products, plastics, organic material, metallics, and the like.
Claims (14)
1. A refrigerating means, comprising:
a. a rotatable drum having means to receive and to discharge material; said drum having an interior configuration which further comprises transport means for advancing the material longitudinally within said drum upon rotation of the drum;
b. rotation means engaging said drum for rotating said drum;
c. an intake header means through which material may be introduced into said drum, juxtaposed to the material receiving end of said drum so that said drum is free to rotate with respect thereto, said intake header means forming a chamber communicating with the interior of said drum;
d. refrigeration means within said drum to refrigerate material while it is within said drum; said refrigeration means further comprising a low temperature fluid introduced within said drum; and e. recirculation means to recirculate said fluid from said chamber of said intake header means, to and through the end of said drum from which material is discharged.
a. a rotatable drum having means to receive and to discharge material; said drum having an interior configuration which further comprises transport means for advancing the material longitudinally within said drum upon rotation of the drum;
b. rotation means engaging said drum for rotating said drum;
c. an intake header means through which material may be introduced into said drum, juxtaposed to the material receiving end of said drum so that said drum is free to rotate with respect thereto, said intake header means forming a chamber communicating with the interior of said drum;
d. refrigeration means within said drum to refrigerate material while it is within said drum; said refrigeration means further comprising a low temperature fluid introduced within said drum; and e. recirculation means to recirculate said fluid from said chamber of said intake header means, to and through the end of said drum from which material is discharged.
2. A refrigerating means according to claim 1, wherein said header means includes means passing therethrough for introducing material through said chamber into said drum, said last-mentioned means comprising a chute; and said header means being divided into a plurality of chambers separated from one another by a partition having an opening therein; and said chute passing through said opening; said opening having a door biased normally closed for automatically allowing material to pass through said partition and for automatically closing once material has passed therethrough.
3. A refrigerating means according to claim 2, wherein said header means has a second door disposed in an opening in the wall of said header means, and said chute passes through said opening; said second door automatically allowing material to pass therethrough and automatically closing after material has passed therethrough; stack means being provided for withdrawing air and gas from said chambers.
4. A refrigerating means according to claim 3, wherein said stack means comprises a stack communicating with the chamber having said second door opening therein;
said stack having mounted therein a fan to withdraw air and gas from said chambers.
said stack having mounted therein a fan to withdraw air and gas from said chambers.
5. A refrigerating means according to claim 2, 3 or 4, wherein said refrigeration means further comprises gas recirculation means communicating with the chamber within said header for withdrawing gas from said header and said drum and recirculating it externally to and through the discharge of said drum, thereby creating a gas flow within said drum counter to the direction of travel of the material through said drum.
6. A refrigerating means according to claim 2, wherein said refrigeration means further comprises gas recirculation means communicating with the chamber within said header for withdrawing gas from said header and said drum and recirculating it externally to and through the discharge of said drum, thereby creating a gas flow within said drum counter to the direction of travel of the material through said drum; said gas recirculation means further comprising a conduit communicating with said chamber; a recirculating fan communicating with said conduit; a conduit communicating the discharge end of said recirculating fan with the discharge end of said drum; and an excess gas discharge means communicating with said last mentioned conduit.
7. A refrigerating means according to claim 6, wherein said excess gas discharge means comprises a valve controlled discharge pipe and a means for monitoring the flow of gas through said conduit to said discharge end of said drum.
8. A refrigerating means according to claim 1, including heating means between said header means and said drum to prevent frost buildup therebetween.
9. A refrigerating means according to claim 8, wherein insulation is provided on said drum proximate to said header means and said heating means.
10. A refrigerating means according to claim 1, wherein said header means further comprising a controlled mechanical feeder.
11. A refrigerating means according to claim 1, including stack means for withdrawing air and gas from said chamber.
12. A refrigerating means according to claim 11, wherein said stack means comprises a stack having mounted therein a fan to withdraw air and gas from said chamber.
13. A refrigerating means according to claim 1, including reciprocating feeder means for shaking material placed therein into said drum at a preselected controlled rate of introduction of material into said drum for subsequent refrigeration within said drum.
14. A refrigerating means according to claim 13, wherein temperature sensing means are provided within the refrigerating means to control the rotation of said drum and the feeder means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US365117A US3906743A (en) | 1973-05-30 | 1973-05-30 | Refrigeration apparatus having a rotatable drum |
| CA201,110A CA1031589A (en) | 1973-05-30 | 1974-05-29 | Apparatus and process for refrigerating materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1054814A true CA1054814A (en) | 1979-05-22 |
Family
ID=25667593
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA297,568A Expired CA1054813A (en) | 1973-05-30 | 1978-02-23 | Apparatus for refrigerating materials |
| CA297,569A Expired CA1054814A (en) | 1973-05-30 | 1978-02-23 | Apparatus for refrigerating materials |
| CA297,570A Expired CA1054815A (en) | 1973-05-30 | 1978-02-23 | Apparatus for refrigerating materials |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA297,568A Expired CA1054813A (en) | 1973-05-30 | 1978-02-23 | Apparatus for refrigerating materials |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA297,570A Expired CA1054815A (en) | 1973-05-30 | 1978-02-23 | Apparatus for refrigerating materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (3) | CA1054813A (en) |
-
1978
- 1978-02-23 CA CA297,568A patent/CA1054813A/en not_active Expired
- 1978-02-23 CA CA297,569A patent/CA1054814A/en not_active Expired
- 1978-02-23 CA CA297,570A patent/CA1054815A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CA1054813A (en) | 1979-05-22 |
| CA1054815A (en) | 1979-05-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3906743A (en) | Refrigeration apparatus having a rotatable drum | |
| US4033142A (en) | Apparatus for refrigerating materials | |
| US4084387A (en) | Apparatus and process for refrigerating materials | |
| EP0361700B1 (en) | Combination cryogenic and mechanical freezing system | |
| CA2086551C (en) | Combination cryogenic and mechanical freezer apparatus | |
| US4033048A (en) | Freeze drying apparatus | |
| US20190201936A1 (en) | Method and apparatus for separating trichomes from cannabis plant material | |
| US2951353A (en) | Apparatus for refrigerating such perishable materials as foodstuffs | |
| EP0372354B1 (en) | Tunnel freezer | |
| KR100852668B1 (en) | Refrigerator and apparatus for ice discharging therein | |
| US3914953A (en) | Cryogenic fragmentation freezer | |
| EP0005926A2 (en) | Cryogenic freezer and method of operating the same | |
| CA1091922A (en) | Rotary retort furnace | |
| CA1054814A (en) | Apparatus for refrigerating materials | |
| GB986038A (en) | Improvements in or relating to apparatus and methods of heating food products | |
| CA1112048A (en) | Deflashing apparatus | |
| US4301659A (en) | Fluidized freezing | |
| DE3777872D1 (en) | DEVICE FOR FAST COOLING OR SHOCK FROSTING OF ROCKETABLE PRODUCTS. | |
| US4281521A (en) | Fluidized freezing | |
| US20220170686A1 (en) | Cooling system | |
| CN210479877U (en) | Conveying device of tunnel refrigerator | |
| CN111288724B (en) | Impact type quick freezing machine | |
| EP0341131B1 (en) | Enclosure and method for thermal treatment with a cooling step | |
| US6059640A (en) | Cryogenic deflashing apparatus | |
| CN211721712U (en) | Corbicula fluminea separation refrigerator |