US2718123A

US2718123A - Ice making apparatus

Info

Publication number: US2718123A
Application number: US300923A
Authority: US
Inventors: Jr James W Braswell
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-07-25
Filing date: 1952-07-25
Publication date: 1955-09-20
Anticipated expiration: 1972-09-20

Description

J. W. BRASWELL, JR

ICE MAKING APPARATUS Sept. 20, 1955 2 Sheets-Sheet 1 Filed July 25, 1952 INVENTOR I J \MBrasweN'J ATTORNEY Sept. 20, 1955 J. w. BRASWELL, JR

ICE MAKING APPARATUS 2 Sheets-Sheet 2 Filed July 25, 1952 J? W- Brasw lf, Jx

' dbmw ATTORNEY United States Parent 2,718,123 icE MAKING APPARATUS James W. Braswell, Jr., Midway Park, N. c. Application July 25, 1952, Serial'No. 300,923

Claims. c1. '62-106) My invention relates to a machine for making ice.

An important object of the invention is to provide a machine for making separate ice units in a'water mass, the ice units separating from the freezing means by partial melting, and then floating to the top of the water mass for harvesting.

A further object of the invention is to provide a machine of the above-mentioned character, having the combined freezing and melting elements arranged exteriorly of the watertank and contacting therewith at spaced intervals.

A further object of the invention is to provide means for alternately supplying a cold liquid refrigerant and a hot liquid refrigerant to the tubular elements for forming the ice units within the tank and partly melting the ice units to free them from the side wall of the tank.

A further object is to provide. means wherein the expansion or vaporization of the liquid refrigerant occurs exteriorly of the freezing and melting elements, for forming the cold liquid refrigerant and the gaseous refrigerant to be supplied to the compressor for producing the hot liquid refrigerant.

A further object is to provide in an ice making machine of the above-mentioned character a novel pressure regulating device used to establish a required pressure differential between the hot and cold liquids of the system, and compensating for variable conditions of the compressor.

A further object is to provide in a machine of the abovementioned character means for controlling the shape and size of the ice particles.

A further object is to provide in a machine of the abovementioned character automatic valve means for maintaining the necessary volume of liquid refrigerant within the system at all times.

A still further object of the invention is to provide a machine of the above-mentioned character which is highly simplified in construction, reliable and efiicient in operation and entirely automatic.

Other objects and advantages of the invention will bev apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts, throughout the same,

Figure l is a central vertical section, partly diagrammatic, through an ice making machine embodying my invention, parts in elevation, I v

Figure 2 is a horizontal cross section taken substantially on line 2-2 of Figure l,

Figure 3 is an enlarged central vertical section through a surge tank and refrigerant float valve, parts broken away,

Figure 4 is a similar section through a pressure regulating device of the machine,

Figure 5 is a similar section through a master valve, Figure 6 is a horizontal cross section on line 66 of Figure 5, Y

Figure 7 is an enlarged fragmentary side elevation of a 2,718,123 Patented Sept. 20, 1955 "ice valve disc in the master valve and showing an elongated port formed therein, and

Figure 8 is an enlarged vertical section through a header of the machine and showing a ball check valve arranged therein, parts in elevation.

In the drawings, Where for the purpose of illustration is shown a preferred embodiment of my invention, the numeral 10 designates a vertical tank or casing closed at its bottom and having an upper tapered end portion 11. The tank 10 holds water to be frozen in producing ice particles and the level of the water in the tank is indicated at L, Figure 1. The ice units or particles 12 formed by the machine are frozen upon the inner face of the tank 10, and when melted therefrom are released and float upwardly to the level L. At the surface, the ice particles 12 are scooped up by a horizontal conveyor 13 and fed lengthwise through the conveyor. The conveyor is driven by a motor and may be substantially the construction shown in my Patent Number 2,590,499.

The level of the water in the tank 10 is maintained constant byv a float operated valve 14, receiving water under pressure from a pipe 15. When the valve 14 opens to supply additional water to the tank 10, this water is discharged through a pipe 16. When the level of the water is re-' stored to normal, the valve 14 automatically closes. The pipe 16 extends above the conveyor 13 so that the incoming water is sprayed over the rotary conveyor. 'By thus spraying the incoming water, it is freed of air, and by so doing, prevents the formation of white ice particles. As shown in Figure l; the ice particles 12 may be circular discs of ice which are formed upon the inner surface of the tank 10 as previously stated, and as will be more fully described hereinafter.

Surrounding the vertical tank 10 are circumferentially spaced combined freezing and melting tubular elements 17. The elements 17 extend vertically, and are bent at intervals throughout the major portion of their lengths for providing inner U-shaped contacting portions18 which contact the outer surface of the tank 10 at vertically spaced points 19. The elements 17 may be soldered or otherwise secured to the tank. 10, and the elements 17 are preferably thirty in number, as indicated.

Each vertical tubular element 17 is provided at its top with a reduced pipe 20, having a small bore to serve as a liquid refrigerant restrictor port. The reduced pipes 20 are connected with and discharge into an enlarged annular header or pipe 21. When the liquid refrigerant, cold or hot, passes through the reduced pipes 20 having this header functions as an evaporator, and the liquid refrigerant is partly converted into a gas, and the expanding gas extracts heat from the remaining liquid refrigerant which has its temperature reduced in the header 21 to approximately 10 degrees F.

Arranged exteriorly of and near the tank 1%) is a vertical surge tank 22 having its bottom and top ends closed. A pipe 23 leads into the top of the surge tank 22 and into the evaporator header 21. The pipe 23 has a relatively large diameter, as compared to the elements 17. Also leading into the top of the surge tank 22 is a pipe 24 of relatively large diameter, leading to the intake side of a compressor 25. When the liquid refrigerant, cold or hot, passes through the restrictor pipes 20 and enters the evaporator header 21, the liquid refrigerant vaporizes in part, as stated, and the vaporizing refrigfrigerant passes upwardly through the pipe 24 and is sup plied to the intake side of the compressor 25.

Connected with the outlet side of the compressor 25 is a condenser coil 26, receiving hot compressed refrigerant vapor from the compressor, which is converted into liquid while passing through the condenser coil 26, before discharging into a receiver tank 27. The liquid refrigerant within the tank 27 is hot and has a temperature of approximately 110. degrees F. An outlet pipe 23 is connected with the receiver tank 27 and leads to a master valve 29, This master valve includes a vertical casing 30, having a top 31, Figure 5, provided with a tapered portion 32. A horizontal tapered valve disc 33 slidabl'y engages the tapered portion 32 and has a circumferentially elongated opening or slot 34 formed therein which extends through the top and bottom edges of the same, as shown in Figures 5 and 7. The valve disc 33 is rigsecured to a vertical shaft 35, mounted in a fixed bearing 36, and carrying a worm wheel 37. The shaft 35 is urged upwardly by a compressible coil spring 38 which serves to hold the valve disc 33 in sliding contact with the tapered portion 32. The worm wheel 37 is driven by a worm' 39, Figure 6, formed upon a horizontal shaft 40, carrying a second worm wheel 41, driven by a worm 42, carried by a vertical shaft 43 The shaft 43 is driven by a motor 44. The casing 3.3 may be partially filled with oil, which also enters the casing sec: tion 45, enclosing the gearing including the elements 42 and 43. The oil and air in the casing sections 30 and. 4.5 form'a seal between the motor 44 and the hot aiquid refrigerant entering the master valve 29 from the pipe 28. This arrangement prevents the refrigerant from causing any damage to the copper parts of the motor 44.

Arranged beneath the tank 10 is an annular horizontal tubular header 46, connected with a radial pipe 47, connected with the outlet side of a rotary pump 48, the intake side of which is connected with a pipe 49, leading to the lower end of the surge tank 22, which holds the cold liquid refrigerant. The hot liquid refrigerant is supplied to the lower end of each tubular element 17 through a pipe 50, and this pipe leads into a tubular header 51, connected with the lower end of the tubular element 17. The header 51 has a valve seat 52 adjacent to the pipe 50, and an inverted V-shaped deflector 53 is arranged upon one side of the valve seat. The element 54 is a ball check valve to engage the valve seat 52. Cold liquid refrigerant is supplied to the lower end of each tubular element 17 through a pipe 55, connected with the annular header 46 and the lower end of the particular tubular header 51. The tubular header 51 has a second valve seat 56 adjacent to. the pipe 55, Fig ure 8.

The ball check valve 54, is adapted to alternately engage the valve seats, 52 and 56. When the hot liquid refrigerant is being supplied from the master valve 29; to the lower end of one tubular element 17, the incoming hot liquid refrigerant, being at a higher pressure than the cold liquid refrigerant, unseats the ball check valve 54 which is thrown over the deflector 5 3 an engages the valve seat 56, thus preventing the hot liquid refrigerant from entering the pipe 55.. When the freezing cycle is occurring and the supply of hot liquid is cut oi by the valve disc 33, cold'liquid refrigerant passes through the pipe 55 and unseats the ball check valve 54, from the seat 56 and causes it to engage the seat 52, thus preventing the cold liquid refrigerant from entering the pipe 50.

Connected in the pipe 47 is a pressure regulating device or valve 57, having a valve element 58 which is regulated by a reciprocatory stem 59., secured to a flexe. di phr 0 i h e asin e o 61- A, ube 62 leads from the pipe-28 into the casing section 61 above the diaphragm 60, as shown, The pressure regulating valve 57 has an intermediate tubular casing section, 63 surrounding the stem 59 and spaced therefrom to, form a, passage 62', leading into, the casing section 61 below the diaphragm 60. The passage 62 also leads into. a

lower casing section 63 of the pressure regulating valve,

within which the valve elements 58 operate.

The pressure of the hot liquid from the tube 62 acts upon the top of the diaphragm 60, and tends to force the valve element 58 open, which allows more cold liquid from the pipe 47 to flow through the valve 58 and into the header 46. This elevates the pressure in the header 46, and this pressure acts against the bottom of the diaphragm 60, tending to cause the valve element 58 to throttle or close. This throttling action effects a predetermined pressure dilferential between the hot and cold liquid refrigerant flowing in the system. This is necessary because the hot liquid pressure must be slightly higher than the cold liquid pressure, so that it can force its way into the header 51 against the pressure of the cold liquid refrigerant. The pressure of the hot liquid will vary with the conditions under which the system must operate. Weather temperature, condenser water temperature, etc., will affect the operating pressures of the machine, and the valve device 57 maintains the proper differential in pressure between the hot and cold liquid in the system. The cold liquid from the casing section 63' passes through the passage 62, in order to reach the bottom of the diaphragm 60.

A float controlled valve 64 is mounted upon the side of the surge tank 22, and embodies a float 65. Should the level of the cold liquid refrigerant in they surge tank fall below the selected level, the float 65 will open the valve and hot liquid refrigerant will be supplied to the tank 22 through a pipe 66, connected with the pipe 28.

A valve 67 is connected inthe pipe 28 and is held open by a solenoid 68 when the solenoid is energized. The solenoid 68 is connected with

wires

69 and 70, as shown. Contacts 71, Figure 3, are connected in the wire 70, and when the level of the cold liquid refrigerant in the tank 22 rises above a selected point, the float 65 breaks the electrical connection between the contacts 71, and the solenoid 68 is deenergized, and the valve 67 closes.

The operation of the machine is as follows:

The freezing cycle of the machine takes place simultaneously in all of the tubular elements 17 except one, which is simultaneously defrosted by the action of the hot liquid refrigerant. Considering the freezing cycle, the cold liquid refrigerant passes from the header 46 through the pipes 55 and unseats the ball check valves 54 which will now engage the valve seats 52. The cold liquid refrigerant will now pass upwardly through all of the tubular elements 17 except the single element which is being defrosted. The cold liquid refrigerant has a temperature of about 10 degrees F., as previously stated, Since the portions 18 of the elements 17' are in thermal contact with the outer face of the tank 10, the ice particles or discs 12 will form upon the inner face of the tank 10 at the points 19, and surrounding the same. The surface of the inner face of the tank where the ice is formed remains relatively free of corrosion while the remainder of the surface corrodes to a certain extent and gathers foreign matter from the water. This corrosive action increases the heat insulating properties of the side wall of the tank and confines the non-corroded areas of the tank adjacent to the points 19, thereby limiting the size of the circular ice discs 12 formed by the machine. The ice discs 12 are thus maintained separate, and will not contact and freeze together into an integral mass, but will readily separate individually from the tank and float to the surface L, when partially melted by the defrosting of the individual elements 17.

While twenty-nine of the elements 17 are receiving the cold liquid refrigerant, and causing the formation of the ice. particles 12, one of the elements 17 is receiving hot liquid refrigerant and being defrosted thereby for releasing the adjacent ice particles 12 from the tank, so that they may float to hesurfaee L andxbe harvested. The defrosting cycle is regulated by the valve disc 33 which is turning very slowly, in order to provide a suitable time interval for any particular element 17. The speed of rotation of the valve disc 33 is preferabiy about four revolutions per hour.

When the single elongated port 34 of the valve disc 33 moves into registration with one pipe 50, the hot liquid refrigerant from the master valve 29 now passes through the particular pipe 50 and enters the particular header 51. The hot liquid refrigerant unseats the ball check valve 54, which is now transferred to the seat 56. The hot liquid refrigerant is under higher pressure than the cold liquid refrigerant, as controlled by thepressure regulator 57, so that the ball check valve 54 will remain seated upon the seat 56 during the defrosting cycle, which is defined by the circumferential length of the port 34, and speed of rotation of the valve disc 33. The hot liquid refrigerant flowing through the tubular element 17 heats the tank adjacent to the ice particles 12, and sufficiently melts the ice particles to free them from the side wall of the tank It The heated refrigerant of course forces the cold liquid refrigerant from the tubular element 17, and the cold and hot liquid refrigerant both discharge through the restrictor pipe 20 into the evaporator header 21. At the end of the defrosting cycle for the particular element 17, the port 34 moves out of registration with the particular pipe 50 and the cold liquid refrigerant is again supplied through the pipe 55 to the particular header 51 and tubular element 17, so that the freezing cycle may again start. The port 34 then movesinto registration with another of the pipes 50, so that the defrosting cycle may take place in another of the tubular elements 17, while the freezing cycle continues in the other twenty-nine elements 17.

The cold and hot liquid refrigerant discharging from the several elements 17 through the restrictor pipes 20, enters the annular evaporator header 21, where its pressure is reduced, and a portion of the liquid refrigerant vaporizes in the header 21, and this reduces the temperature of the remaining liquid refrigerant to approximately 10 degrees F. This cold liquid refrigerant is discharged downwardly into the surge tank 22, while the vaporized refrigerant passes through the pipe 24 to the compressor 25. The compressed refrigerant discharges into the condenser 26 and the hot liquid refrigerant is held in the receiver tank 27. The hot liquid refrigerant is supplied from the tank 27 to the master valve 29, by way of the pipe 28.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangements of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoine'd claims.

Having thus described my invention, I claim:

1. An ice making machine comprising a tank for holding water, a plurality of tubular elements arranged exteriorly of the tank and formed to contact the outer surface of the tank at a plurality of spaced points, means connected with corresponding ends of the tubular elements for alternately introducingcold and hot liquid refrigerant into the tubular elements and causing the liquid refrigerant to pass through the elements, restrictor pipes connected with the other corresponding ends of the tubular elements and having reduced restrictor bores receiving the liquid refrigerant from the tubular elements, and evaporator means including a common evaporator header connected with the restrictor pipes and having a relatively large bore for receiving the refrigerant from the restrictor pipes and effecting a partial vaporization of the same.

2. A machine for making ice comprising a tank adapted to hold water, automatic valve means connected with the tank for spraying water into the top of the tank and maintaining a substantially constant level of water near the top of the tank, a rotary conveyor element mounted upon the tank near the level of the water and adapted to harvest ice particles Which are formed within the tank and float to the top thereof, a plurality of tubular elements arranged exteriorly of the tank and being in thermal contact with the outer face of the tank at spaced points and adapted to receive a refrigerant, means connected with 5;; the tubular elements for alternately introducing cold and hot liquid refrigerant into the same, and evaporator means connected with the tubular elements and receiving the liquid refrigerant therefrom and partially vaporizing the same.

3. An ice making machine comprising a tank for bolding water, a plurality of tubular elements arranged exteriorly of the tank and contacting the outer surface of the tank at a plurality of spaced intervals, evaporator means connected with corresponding ends of the tubular elements for receiving a liquid refrigerant therefrom and effecting partial vaporization of the liquid refrigerant, a surge tank connected with said evaporator means and receiving liquid and vaporized refrigerant therefrom, means connected with the surge tank for receiving the vaporized refrigerant therefrom and compressing the same and subsequently condensing the vaporized refrigerant to form hot liquid refrigerant, headers connected with the other corresponding ends of the tubular elements and having two-way check valves for permitting hot or cold liquid refrigerant to enter the headers and tubular elements, conduit means connecting the surge tank and headers for conveying cold liquid refrigerant from the surge tank to the headers when the two way check valves of the headers are in one position, and separate conduit means connecting the headers and said means connected with the surge tank for conducting hot liquid refrigerant to the headers when the two way check valves are in the other position.

4. An ice making machine comprising a tank for holding water, a plurality of tubular elements arranged ex- 3 teriorly of the tank and contacting the outer surface of the tank at a plurality of spaced intervals, evaporator means connected with corresponding ends of the tubular elements and receiving liquid refrigerant therefrom and effecting partial vaporization of the liquid refrigerant, a

r surge tank connected with said evaporator means and receiving liquid and vaporized refrigerant therefrom, a

compressor connected with the surge tank and receiving the vaporized refrigerant therefrom and compressing the same, condenser means connected with the compressor 4 gpand receiving the compressed vaporized refrigerant therefrom and condensing the same to form hot liquid refrigerant, headers connected with the other corresponding ends of the tubular elements and having two Way check valves for permitting hot or cold liquid refrigerant to 5Q 6nlr the headers and tubular elements, conduit means connecting the surge tank and headers for conducting cold liquid refrigerant from the surge tank to the headers when the two way check valves of the headers are in one position, and a master valve connected with said condenser means and with all of said headers and receiving hot liquid refrigerant from the condenser means, the master valve including a movable metering part arranged to permit passage of the hot liquid refrigerant into one header only when the two way check valve of such header .;is in the other position and while the other headers are receiving cold liquid refrigerant from said conduit means.

5. An ice making machine comprising a tank for holding water, a plurality of tubular freezing elements arranged exteriorly of the tank and contacting the outer surface of the tank, evaporator means connected with corresponding ends of the tubular freezing elements and receiving liquid refrigerant therefrom and effecting partial vaporization of the liquid refrigerant, a surge tank connected with said evaporator means and receiving liquid ,and vaporized refrigerant therefrom, a compressor connected with the surge tank and receiving the vaporized refrigerant therefrom and compressing the same, condenser means connected with the compressor and receiving compressed vaporized refrigerant therefrom and condensing the same to form hot liquid refrigerant, headers connected with the other corresponding ends of the tubular freezer elements and having two way check valves permitting hot or cold liquid refrigerant to enter the headers and tubular freezing elements, conduit means connecting the surge tank and headers for conducting cold liquid refrigerant from the surge tank to the headers when the two way check valves of the headers are in one position, a pump connected in said conduit means to propel the cold liquid refrigerant therethrough, a master valve including a rotary metering part having port, a pipe connecting the master valve with said condenser means and conducting hot liquid refrigerant to the master valve, a plurality of pipes connecting the master valve and headers and adapted to alternately register with the port of the rotary metering part, whereby hot liquid refrigerant is introduced into one of said headers while the other headers are receiving cold liquid refrigerant from the conduit means, and a pressure regulating device connected with the conduit means and said pipe connecting the master valve and condenser means and maintaining a pressure differential between the hot and cold liquid refrigerant.

6. An ice making machine comprising a tank to hold water, a plurality of tubular freezer elements arranged exteriorly of the tank and contacting the outer surface thereof, evaporator means connected with the tubular freezer elements and receiving liquid refrigerant therefrom and partially vaporizing the refrigerant, a surge tank connected with said evaporator means and receiving liquid and vaporized refrigerant therefrom, the liquid refrigerant passing to the bottom of the surge tank and the vaporized refrigerant accumulating in the upper portion of the surge tank, a compressor connected with the upper portion of the surge tank and receiving the vaporized refrigerant therefrom and compressing the same, condenser means connected with the compressor and receiving the compressed vaporized refrigerant therefrom and condensing the same to form hot liquid refrigerant, valve devices connected with the tubular freezer elements for permitting hot or cold liquid refrigerant to enter the same, conduit means connected with the surge tank near its lower end connected with the valve devices for conducting cold liquid refrigerant to the same, a master valve including a movable metering part, having a port, a pipe connecting the master valve and said condensor means and conducting hot liquid refrigerant to the master valve, a plurality of pipes connecting the master valve and said valve devices and adapted to register with the port of the movable metering part, whereby hot liquid refrigerant is introduced into one of thetubular freezer elements while the other elements are receiving cold liquid refrigerant from the conduit means, and automatic valve means connected with the surge tank and said pipe for causing hot liquid refrigerant from the pipe to enter the surge tank and maintain a constant level of liquid refrigerant Within the surge tank.

7. In an ice making machine, a tank to hold water, tubular freezer elements arranged upon the outer surface of the tank and thermally contacting the outer surface of the tank at spaced intervals, evaporator means connected with the tubular freezer elements and receiving liquid refrigerant therefrom andpartially vaporizing the refrigerant, a surge tank connected with the evaporator means and receiving liquid and vaporized refrigerant therefrom, mechanical refrigeration means connected with the surge tank and receiving the vaporized refrigerant therefrom and compressing and condensing the same to form hot liquid refrigerant, conduit means connecting the surge tank and tubular freezer elements and conducting cold liquid refrigerant to the elements so that they may effect the freezing of ice particles upon the inner surface of' the tank, a master valve connected with the mechanical refrigeration means and receiving the hot liquid refrigerant therefrom, and a plurality of pipes connected with the master valve and tubular freezer elements, the master valve including a rotating disc having a single elongated opening formed therein for alternate registration with said pipes, whereby the hot liquid refrigerant is conducted to one of said tubular freezer elements while the other elements are receiving the cold liquid refrigerant.

8. An ice making machine comprising a tank to hold water, a plurality of elongated tubular elements arranged exteriorly of the tank and formed to contact the tank at a plurality of spaced points along their lengths, restrictor pipes connected with corresponding ends of the tubular elements for receiving liquid refrigerant therefrom, a substantially annular evaporator header connected with restrictor pipes and having a relatively large bore and receiving the liquid refrigerant from the restrictor pipes and effecting partial vaporization of the same, a surge tank connected with the evaporator header and receiving a mixture of liquid and vaporized refrigerant therefrom, mechanical refrigeration means connected with the surge tank and receiving vaporized refrigerant therefrom and compressing and condensing the vaporized refrigerant to form hot liquid refrigerant, headers having two way check valves connected with the other corresponding ends of the tubular elements, a substantially annular header arranged near said headers and connected with the surge tank and receiving cold liquid refrigerant therefrom, pipes connecting the last named annular header with said headers for conducting cold liquid refrigerant thereto, a master valve connected with the mechanical refrigeration means and receiving hot liquid refrigerant therefrom, and pipes connected with the master valve and with said headers for conveying the hot liquid refrigerant thereto.

9. An ice making machine comprising a tank for holding water, a plurality of tubular elements arranged adjacent to a wall of the tank and being in thermal contact with the wall of the tank, means connected with corresponding ends of the tubular elements for alternately introducing cold and hot liquid refrigerant into the tubular elements and causing the liquid refrigerant to pass through said elements, restrictor devices connected with the other corresponding ends of the tubular elements and receiving the liquid refrigerant from the tubular elements, and evaporator means connected with the restrictor devices and receiving the refrigerant from the restrictor devices and effecting partial vaporization of the same.

10. An ice making machine comprising a tank for holding water, a plurality of tubular elements arranged adjacent to a wall of the tank and being in thermal contact with said wall, means connected with corresponding ends of the tubular elements for alternately introducing cold and hot liquid refrigerant into the tubular elements and causing the liquid refrigerant to pass through said elements, restrictor pipes connected with the other corresponding ends of the tubular elements and having reduced restrictor bores receiving the liquid refrigerant from the tubular elements, and a common evaporator header connected with the restrictor pipes and receiving the refrigerant from the restrictor pipes and effecting partial vaporization of the same.

References Cited in the file of this patent UNITED STATES PATENTS 1,963,842 Gay u June 19, 1934 2,145,774 Muffly Jan. 31, 1939 2,145,775 Muffiy Jan. 31, 1939 2,145,777 Mufiiy Ian. 31, 1939 2,387,899 Gruner Oct. 30, 1945 2,538,097 Henderson Jan. 16, 195.1 2,544,394 Muffly Mar. 6, 1951 2,572,508 Mufiiy Oct. 23, 1951 2,628,479 Powers Feb. 17, 1953 2,641,109 Muffiy June 9, 1953 2,695,502 Muffiy Nov. 30, 1954 2,700,280 Heuser Jan. 25, 1955