Patent US3751935A successfully refreshed from Google Patents.
US3751935A
Expired / Lapsed
US
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Method and system for creating and maintaining an ice slab
Assignee: Calmac Manufacturing Corp
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Filing: 1971-12-02
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Granted: 1973-08-14
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Expires: 1991-12-02
Abstract
Abstract Method and system for creating and maintaining an ice slab for skating purposes, or an ice chute for a toboggan slide, or for maintaing a layer of snow for skiing. The system includes pluralities of small diameter flexible plastic tubes arranged in grids in portable mats with the tubes placed close to one another and arranged with each input or supply tube portion closely adjacent to an outlet or return tube portion providing an advantageous uniform temperature effect at a small distance above the tubes. A low temperature anti-freeze liquid is pumped through the tubes to provide the desired uniform cooling effect, and the portable mats each include a pair of sub-headers which can conveniently be coupled together with main headers to form a large grid the size of an ice skating rink, or a ski slope. For a rink these small flexible tubes may thereafter be covered with a thin layer of sand, or other protective material, and water is then introduced into the rink and is frozen by the low temperature refrigerant passing through the various tubes. By virtue of the small diameter of the tubes, ethylene glycol or other similar low temperature anti-freeze liquid (which would be very expensive with conventional systems) can economically be used to practice the invention disclosed herein. In the case of a ski slope, the small flexible tubes are covered with a thin layer of sand or dirt, and the circulation of the low temperature refrigerant serves to maintain, i.e. to ''''hold'''', a skiable layer of snow (either natural or manmade snow or a mixture of them) on the ski slope during thawing periods when the snow normally would melt away.
Inventors
- 👤 C Maccracken
- 👤 H Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:04
CPC Classifications
F; F25; F25C; F25C3/00; F25C3/02
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
208 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preparing a layer of thermal insulation material over such area, c. overlaying said insulated area with parallel lengths of small diameter flexible plastic tubing of between one-eighth and three-eighths inch inside diameter which have been preassembled into mats of multiple tube lengths by means of spacer attachments, holding the flexible parallel tube lengths in spaced relationship to one another at regular intervals along the tube lengths, d. connecting such tube lengths at their ends at the border of said area to supply and return header pipes, e. circulating low temperature anti-freeze liquid through said header pipes and tubes with flow of said liquid in adjacent parallel tube lengths being in alternate directions, f. refrigerating said low temperature anti-freeze liquid to a temperature of no more than 10* F, g. placing a layer of protective material over the flexible plastic tube lengths, h. putting water over said protective material to be frozen into the slab of skating ice, and i. freezing the slab of ice to a thickness greater than threefourths of an inch to provide a uniform slab of ice for skating.
Claim 2
Independent Claim
208 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preparing a layer of thermal insulation material over such area, c. overlaying said insulated area with parallel lengths of small diameter flexible plastic tubing of between one-eighth and three-eighths inch inside diameter which have been preassembled into mats of multiple tube lengths by means of spacer attachments, holding the flexible parallel tube lengths in spaced relationship to one another at regular intervals along the tube lengths, d. connecting such tube lengths at their ends at the border of said area to supply and return header pipes, e. circulating low temperature anti-freeze liquid through said header pipes and tubes with flow of said liquid in adjacent parallel tube lengths being in alternate directions, f. refrigerating said low temperature anti-freeze liquid to a temperature of no more than 10* F, g. placing a layer of protective material over the flexible plastic tube lengths, h. putting water over said protective material to be frozen into the slab of skating ice, and i. freezing the slab of ice to a thickness greater than threefourths of an inch to provide a uniform slab of ice for skating.
Claim 3
Dependent Claim
36 words
The method of creating a uniform slab of ice for skating as claimed in claim 1, including the step of placing a layer of surfacing material upon the ground before applying said layer of thermal insulation.
Claim 4
Dependent Claim
36 words
The method of creating a uniform slab of ice for skating as claimed in claim 1 in which said parallel tube lengths are spaced apart from one-half inch to 1 1/2 inches from center-to-center on average.
Claim 5
Dependent Claim
93 words
The method of creating a uniform slab of ice for skating as claimed in claim 1 in which said plastic tube lengths run lengthwise beneath the ice slab wherein every other tube length is connected to a supply header near one end of the ice slab and runs to a return header at the other end of the ice slab and each interventing tube length is connected to a supply header at said other end of the ice slab and runs to a return header at said one end of the ice slab.
Claim 6
Dependent Claim
87 words
The method of creating a uniform slab of ice for skating as claimed in claim 1 in which the plastic tube lengths run across beneath the shorter dimension of the ice slab and each pair of tube lengths are connected to each other at one side of the ice slab and one of each pair runs to a supply header at the other side of the ice slab and the other of each pair runs to a return header at said other side of the ice slab.
Claim 7
Independent Claim
237 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats wherein the lengths of tubing are secured in a grid relationship in closely spaced neighboring relationship, c. laying said mats side by side upon said area, d. connecting the lengths of tubing at their ends near the border of said area to supply and return headers, e. providing anti-freeze coolant capable of being refrigerated down below 10*F without freezing, f. circulating such anti-freeze coolant through said tubing mats with the coolant flow direction being in opposite directions in successive neighboring tubes, g. refrigerating said anti-freeze coolant to a temperature below approximately 10*F, h. pumping the anti-freeze coolant at a flow of less than 1/50 gallon per minute per square foot of area of the ice surface, i. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant in successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperaturs at the ice surface.
Claim 8
Independent Claim
237 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats wherein the lengths of tubing are secured in a grid relationship in closely spaced neighboring relationship, c. laying said mats side by side upon said area, d. connecting the lengths of tubing at their ends near the border of said area to supply and return headers, e. providing anti-freeze coolant capable of being refrigerated down below 10*F without freezing, f. circulating such anti-freeze coolant through said tubing mats with the coolant flow direction being in opposite directions in successive neighboring tubes, g. refrigerating said anti-freeze coolant to a temperature below approximately 10*F, h. pumping the anti-freeze coolant at a flow of less than 1/50 gallon per minute per square foot of area of the ice surface, i. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant in successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperaturs at the ice surface.
Claim 9
Dependent Claim
28 words
The method of creating a uniform slab of ice for skating as claimed in claim 6 wherein the thickness of the ice slab is less than 2 inches.
Claim 10
Independent Claim
278 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. assembling parallel co-extruded pairs of plastic tubing lengths having an inside diameter between one-eighth and three-eighths of an inch for each tubing length of the pair into flexible mats in which the pairs of plastic tubing lengths are in a grid relationship, c. overlaying such area of ground with said mats, d. connecting said pairs of tubing lengths at their ends to supply and return header means leading to and from pumping means for circulating an anti-freeze liquid through said pairs of tubing lengths with the flow of said liquid in the two tubing lengths of each co-extruded pair of tubes in opposite directions, e. pumping the anti-freeze liquid at a flow rate of less than 1/50 gallon per minute per square foot of ice surface, f. refrigerating said anti-freeze liquid to a temperature of no more than 10*F. g. depositing a layer of water over the tops of said pairs of tubing lengths and adding subsequent layers after the previous layer is frozen, until a slab of ice is created having a thickness greater than three-fourths of an inch over the tops of said pairs of tubes, whereby the large temperature difference of the supply and return anti-freeze liquid in the two lengths of tubing in each of said pairs is averaged out partly wIthin the ice slab and partly by heat transfer from the less cold liquid in one of the lengths of tubing of each pair into the colder liquid in the other length of tubing in each pair.
Claim 11
Independent Claim
278 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. assembling parallel co-extruded pairs of plastic tubing lengths having an inside diameter between one-eighth and three-eighths of an inch for each tubing length of the pair into flexible mats in which the pairs of plastic tubing lengths are in a grid relationship, c. overlaying such area of ground with said mats, d. connecting said pairs of tubing lengths at their ends to supply and return header means leading to and from pumping means for circulating an anti-freeze liquid through said pairs of tubing lengths with the flow of said liquid in the two tubing lengths of each co-extruded pair of tubes in opposite directions, e. pumping the anti-freeze liquid at a flow rate of less than 1/50 gallon per minute per square foot of ice surface, f. refrigerating said anti-freeze liquid to a temperature of no more than 10*F. g. depositing a layer of water over the tops of said pairs of tubing lengths and adding subsequent layers after the previous layer is frozen, until a slab of ice is created having a thickness greater than three-fourths of an inch over the tops of said pairs of tubes, whereby the large temperature difference of the supply and return anti-freeze liquid in the two lengths of tubing in each of said pairs is averaged out partly wIthin the ice slab and partly by heat transfer from the less cold liquid in one of the lengths of tubing of each pair into the colder liquid in the other length of tubing in each pair.
Claim 12
Dependent Claim
52 words
The method of creating a uniform slab of ice for skating according to claim 8 in which the two tubing lengths of each pair are joined together at one end of the co-extruded pair by a U-bend and are each connected to supply and return header means, respectively, at their other end.
Claim 13
Dependent Claim
100 words
The method of creating a uniform slab if ice for skating according to claim 8 wherein the two tubing lengths of one pair are connected at their ends by U-bends to tubing lengths of other pairs providing several passes for the anti-freeze liquid across and back beneath the ice slab and wherein the distance along the flow path from any point in one tubing length of a tubing pair to the return header means is equal to the distance from said point along the flow path in the other tubing length of said tubing pair to the supply header means.
Claim 14
Independent Claim
276 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preassembling a plurality of grids of plastic tubing having an inside diameter between one-eighth and three-eights of an inch assembled from multiple tube lengths having length sufficient to extend from one border to another border of said area, said grid being preassembled by fastening each tube length alternately at regular intervals first to the neighboring tube on one side of it and then to the neighboring tube on the other side of it, thus giving each tube a zig-zag course and producing an elongated X-shaped grid pattern of the preassembled tube lengths in each grid, c. covering said area with said grids laid side-to-side, d. connecting such tube lengths at their ends at the border of such area to supply and return header means leading from and to pumping means for circulating anti-freeze liquid through said headers and tubes with the flow of liquid in neighboring tubes being in opposite directions, e. pumping the anti-freeze liquid at a flow rate of less than 1/50 gallon per minute per square foot of said area, f. refrigerating said anti-freeze liquid to a temperature of no more than 10*F, g. depositing a layer of water over said grid of plastic tubing and adding subsequent layers after the previous layer has frozen until a slab of ice is created having a thickness exceeding three-fourths of an inch, whereby the large temperature difference between the anti-freeze liquid in alternate tubes is averaged out within the ice slab, providing substantially uniform temperature at the ice surface.
Claim 15
Independent Claim
276 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area of ground, b. preassembling a plurality of grids of plastic tubing having an inside diameter between one-eighth and three-eights of an inch assembled from multiple tube lengths having length sufficient to extend from one border to another border of said area, said grid being preassembled by fastening each tube length alternately at regular intervals first to the neighboring tube on one side of it and then to the neighboring tube on the other side of it, thus giving each tube a zig-zag course and producing an elongated X-shaped grid pattern of the preassembled tube lengths in each grid, c. covering said area with said grids laid side-to-side, d. connecting such tube lengths at their ends at the border of such area to supply and return header means leading from and to pumping means for circulating anti-freeze liquid through said headers and tubes with the flow of liquid in neighboring tubes being in opposite directions, e. pumping the anti-freeze liquid at a flow rate of less than 1/50 gallon per minute per square foot of said area, f. refrigerating said anti-freeze liquid to a temperature of no more than 10*F, g. depositing a layer of water over said grid of plastic tubing and adding subsequent layers after the previous layer has frozen until a slab of ice is created having a thickness exceeding three-fourths of an inch, whereby the large temperature difference between the anti-freeze liquid in alternate tubes is averaged out within the ice slab, providing substantially uniform temperature at the ice surface.
Claim 16
Dependent Claim
97 words
The method of creating a uniform slab of ice for skating as claimed in claim 6 in which said small diameter flexible plastic tubing is preassembled into mats having a width of only a few feet with a length of many times said width and the ends of said lengths of tubing near said border are connected to supply and return sub-headers having a length approximately equal to the width of said mats, and in which said sub-headers in turn are respectively connected to supply and return main headers extending along said border near the ice slab.
Claim 17
Dependent Claim
98 words
The method of creating a uniform slab of ice for skating as claimed in claim 8, in which said co-extruded pairs of plastic tubing lengths are assembled into flexible mats having a width of only a few feet and having a length of many times said width and including the steps of connecting said pairs of tubing lengths at their ends to supply and return sub-headers having lengths approximately equal to the widths of the mats and in turn connecting said sub-headers, respectively, to main supply and return headers extending along said border area near the ice slab.
Claim 18
Dependent Claim
68 words
The method of creating a uniform slab of ice for skating as claimed in claim 6, including the step of refrigerating said anti-freeze coolant to a temperAture of no more than 5*F and in which the temperature of the antifreeze coolant after circulating through said tubing mats is at a temperature at least 15*F and preferably at least 20*F greater than the temperature to which it is refrigerated.
Claim 19
Independent Claim
234 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats having a width of only a few feet with a length of many times said width wherein the lengths of tubing are secured in a closely spaced grid relationship with average center-to-center spacing distances of from 1/2 of an inch to 1 1/2 inches, c. laying said mats side by side upon said area, d. connecting the lengths of tubing at their ends to supply and return headers, e. providing anti-freeze liquid capable of being refrigerated colder than 5*F without freezing, f. circulating such anti-freeze liquid through said tubing mats with the liquid flow direction being in opposite directions in successive neighboring tube lengths, g. refrigerating said anti-freeze liquid to a temperature of approximately 10*F, h. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant in successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperatures at the ice surface.
Claim 20
Independent Claim
234 words
The method of creating a uniform slab of ice for skating comprising the steps of: a. providing a level and approximately rectangular area, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats having a width of only a few feet with a length of many times said width wherein the lengths of tubing are secured in a closely spaced grid relationship with average center-to-center spacing distances of from 1/2 of an inch to 1 1/2 inches, c. laying said mats side by side upon said area, d. connecting the lengths of tubing at their ends to supply and return headers, e. providing anti-freeze liquid capable of being refrigerated colder than 5*F without freezing, f. circulating such anti-freeze liquid through said tubing mats with the liquid flow direction being in opposite directions in successive neighboring tube lengths, g. refrigerating said anti-freeze liquid to a temperature of approximately 10*F, h. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant in successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperatures at the ice surface.
Claim 21
Independent Claim
251 words
The method of creating a sloping area of ice for sliding by toboggan, sled, ski or other sliding device comprising the steps of: a. providing a mostly sloping area of generally smooth contour, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats having a width of only a few feet with a length of many times said width wherein the lengths of tubing are secured in a closely spaced grid relationship with average center-to-center spacing distances of from 1/2 of an inch to 1 1/2 inches, c. laying said mats end to end upon said area, d. connecting the lengths of tubing at their ends near the beginning of the next mat to supply and return headers, e. providing anti-freeze liquid capable of being refrigerated colder than 5*F without freezing, f. circulating such anti-freeze liquid through said tubing mats with the liquid flow direction being in opposite directions in successive neighboring tube lengths, g. refrigerating said anti-freeze liquid to a temperature of approximately 10*F. h. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant is successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperatures at the ice surface.
Claim 22
Independent Claim
251 words
The method of creating a sloping area of ice for sliding by toboggan, sled, ski or other sliding device comprising the steps of: a. providing a mostly sloping area of generally smooth contour, b. preassembling lengths of small diameter flexible plastic tubing having an inside diameter of between one-eighth and three-eighths of an inch into flexible mats having a width of only a few feet with a length of many times said width wherein the lengths of tubing are secured in a closely spaced grid relationship with average center-to-center spacing distances of from 1/2 of an inch to 1 1/2 inches, c. laying said mats end to end upon said area, d. connecting the lengths of tubing at their ends near the beginning of the next mat to supply and return headers, e. providing anti-freeze liquid capable of being refrigerated colder than 5*F without freezing, f. circulating such anti-freeze liquid through said tubing mats with the liquid flow direction being in opposite directions in successive neighboring tube lengths, g. refrigerating said anti-freeze liquid to a temperature of approximately 10*F. h. depositing a layer of water above said tubing mats and adding subsequent layers after the previous layer has been frozen, until a slab of ice is created having a thickness exceeding the average center-to-center spacing of the lengths of tubing in said mats, whereby the large temperature difference between the anti-freeze coolant is successive neighboring tubes is averaged out within the ice slab providing substantially uniform temperatures at the ice surface.
References Cited (Backward Citations)
US2878651A
Cited
US3295594A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |