US3299659A

US3299659A - Fluid seal for freezing chamber openings

Info

Publication number: US3299659A
Application number: US444712A
Authority: US
Inventors: Moshe Y Dreksler; Thomas F Sloan
Original assignee: Frick Co Inc
Current assignee: Frick Co Inc
Priority date: 1965-04-01
Filing date: 1965-04-01
Publication date: 1967-01-24
Anticipated expiration: 1984-01-24

Description

Jan. 24, 1967 M. Y. DREKSLER ET AL FLUID SEAL FOR FREEZING CHAMBER OPENINGS Filed April l, 1965 5 Sheets-Sheet l INVENTORS MOSHE Y. DREKSLER THOMAS F. SLOAN ATTORNEY g Jan. 24, 1967 M, Y, DREKSLER ET AL 3,299,659

FLUID SEAL FOR FBEEZING CHAMBER OPENINGS 5 Sheets-Sheet 2 Filed April 1, 1965 MOSHE Y. DREKSLER THOMAS F. SLOAN ,V /w/ /H/ ATTORNEY Jan. 24, 1967 M. Y. DREKsLER ET AL 3,299,659

FLUID SEAL FOR FREEZING CHAMBER OPENINGS 3 Sheets-Sheet 5 Filed April 1, 1965 INVENIORS MOSHE Y. DQEKSLER THOMAS F SLOAN ATTORNEY United States Patent O 3,299,659 FLUID SEAL FOR FREEZING CHAMBER OPENINGS Moshe Y. Dreksler, Waynesboro, and Thomas F. Sloan,

Znllinger, Pa., assignors to Frick Company, Waynesboro, Pa., a corporation of Pennsylvania Filed Apr. 1, 1965, Ser. No. 444,712 8 Claims. (Cl. 62-266) The present invention relates to fluid means and more particularly means for sealing openings in a freezing chamber through which material is carried into and from the chamber by a conveyor.

In freezing chambers having openings through which material is carried by a conveyor into or from the chamber, it has been found necessary to enclose or seal the openings from the ambient atmosphere surrounding the chamber to reduce the rate of accumulation of frost on the evaporator coils or other heat exchange surfaces of the refrigerating system. The problem of reducing frost accumulation on the evaporator coil-s is a particularly vexing problem when the freezing chamber is provided with openings disposed one above the other. In such installations, the cold air passes from the lower opening into the ambient atmosphere because of the differential in pressure existing by virtue of the dense cold, air inside the chamber and the less dense, warm lair outside the chamber. The cold air passing from the inside of the chamber is replaced by warm, moist ambient air entering the upper opening. This situation creates a continuous circulation and loss of cold air from the chamber and entry of warm moist air into the chamber which may be characterized as a reverse chimney effect. Since the warm, ambient air is laden with moisture which rapidly solidifes in the chamber in the form of frost on the interior surfaces of the chamber and, particularly, on the surfaces of the evaporator tube bank, the installation has a relatively short operative life before shutdown of the unit for defrosting.

To solve the problem, various types of flexible mechanical seals have been devised, but none is capable of providing an effective enough seal to prevent passage of air through the opening through a wide range of shapes and sizes of material transported by the conveyor.

It also has been sought to solve the aforementioned problem by inclosing at least the upper openings with insulated vwalls to form an anteroom or chamber adjacent the openings in which chamber dehumidifying devices are installed so that a relatively dry air enters the freezing chamber through the upper opening. While this apparatus solves the problem of rapid frost accumulation within the freezing chamber, it is an expensive solution to the problem. Also, if a similar anteroom is not provided adjacent the lower opening, cold air is lost through that opening, thus reducing the efficiency of the installation.

Accordingly, it is an object of this invention to provide a relatively inexpensive and effective means for sealing the openings of a freezing chamber against the passage of air through those openings.

It is another object of this invention to provide a sealing means adjacent at least the lowermost of two openings in a freezing chamber to prevent air circulation through the freezing chamber in the nature of a reverse chimney effect.

A further object of the present invention is to provide a fluid sealing means adjacent an opening in a freezing chamber cooperatively associated with a mechanical sealing means to effectively prevent the passage of air from the chamber.

It is, therefore, contemplated by this invention to provide a seal for the openings of a freezing chamber, which openings have a conveyor extending therein transporting material through the openings, comprising a mechanical sealing means disposed in the openings cooperatively associated with a uid means for discharging a continuous stream of gaseous fluid, such as air, across the entire opening so as to impinge the conveyor and the material carried on the conveyor to thereby provide a static pressure substantially equal to the air pressure within the freezing chamber. The mechanical seal means, according to this invention, comprises a plurality of spaced, flexible walls which resiliently engage the conveyor and the material transported by'the conveyor. The novel fluid seal means comprises a blower having an elongated, relatively narrow discharge outlet for emitting air in front of and across the entire opening and against the conveyor and/or the material carried on the conveyor.

The invention will be more fully understood from the following detailed description thereof when considered in connection with the accompanying drawings in which:

FIG. 1 is an elevational view of a freezing chamber having two openings therein and with the conveyor omitted for illustrative purposes;

FIG. 2 is a view in section taken substantially along line 2 2 of FIG. l;

FIG. 3 is a fragmentary View in section and on an enlarged scale of one of the openings of the freezing chamber shown in FIGS. l and 2;

FIG. 4 is a fragmentary sectional view taken along line 4--4 of FIG. 3 with a portion of the blower assembly broken away;

FIG. 5 is a sectional view taken substantially along line 5-5 of F IG. 4;

FIG. 6 is a fragmentary view in section showing the inlet central means of the blower assembly; and

FIG. 7 is an exploded view in perspective of the exible wall means of the mechanical seal assembly according to this invention.

Now referring to the drawings and more particularly to FIG. 1, 10 generally designates a freezing chamber installation formed by contiguous, heat insulated walls, including a roof 12 and an end wall 14. The interior 16 of the freezing chamber installation 10 has an evaporation coil (not shown) which may comprise a bank of finned tubes disposed within the freezing chamber and connected to the other suitable refrigerating components of a refrigerating system disposed within or outside of interior 16 of the freezing chamber installation 10. An access port controlled by a door 18 is disposed in end wall 14 to enable an operator to gain access to interior 16 for purposes of inspection and/or repair. Also, in wall 14 is provided two

openings

20 and 22, one of which is for the entry `of material to be frozen while the other opening provides for removal of the frozen material.

As best shown in FIG. 3, each opening is lined or framed by a rectangular shaped duct 24, which comprises a top 26, a bottom 28 and

opposite side walls

30 and 32. Partially extending into each duct 24 are the ends of two

conveyor assemblies

34 and 36, each of which comprises an endless conveyor in the form of a

foraminous belt

38 and 40, rollers 42 and 44, respectively, and a suitable belt driving means (not shown). The material, such as package 46, is carried on the upper course of each of the

foraminous belts

38 and 40 through the duct 24. Each of the ducts 24 may be positioned and secured within the

respective openings

20 and 22 by means of flanges 48 projecting from the top 26 and bottom 28 of the duct and spaced to engage opposite sides of wall 14 adjacent the periphery of the openings. i

A mechanical sealing assembly is disposed within duet 24, which assembly comprises a plurality of flexible walls 50 extending across the width of each

belt

38 and 40 and spaced from each other along the longitudinal axis of the belts to form air locks or chambers therebetween. The spacing of the walls 50 is determined upon the size of the material conveyed, such as a package 46, and the predetermined loading of the conveyor belt so that at least one wall 50 throughout its length is in engagement with a conveyor. Each wall 50 is secured to the inner surface of the top wall 26 of duct 24. As best shown in FIG.` 7, each wall 50 comprises a pair of flexible members or sheets 52, each of which is provided with a plurality of spaced slits extending from one end edge thereof to a point spaced from the opposite end edge to form a plurality of resilient fingers 54. The flexible sheets 52 are held in side-by-side relationship to each other by a U-shaped frame 56 in such manner that the slits of one flexible sheet are laterally offset from the slits of the other flexible sheet so that a finger of one flexible sheet overlaps the slit between adjacent fingers 54 of the other flexible sheet. The frame 56 is secured, as by welding or in some other suitable manner, to the inner surface of top wall 26 of duct 24 so that the distal end of fingers 54 engage the

conveyor belts

38 and 40. The mechanical seal also includes flexible sealing members 58 which are secured to the inner surface of bottom wall 28 of duct 24 and project upwardly so that the distal ends of members 5S engage the return course of

belts

38 and 40. The flexible sealing members 58 are required to prevent the flow of air from interior 16 as will be more fully explained hereinafter. To further seal the openings, each mechanical sealing assembly may include a sealing wall 60 supported by

end walls

30 and 32 of duct 24 between the supply and return course of belt 40. Flexible strips 62 are secured along the upper and lower edges of wall 60 to engage belt 40.

To support packages 46 while being transferred from one

conveyor

34 or 36 to the other, a plurality of support rods 64 are disposed to extend across duct 24 in the space between conveyors.

In addition to the mechanical sealing assembly, the

The blower 66 is arranged and adjusted to provide a stream of .air which upon impingement `against conveyor belt 40 and/ or packages 46 creates a fluid static pressure across the flow area of duct 24 which is substantially equal to the air pressure within freezing chamber 10 adjacent the associated duct 24. To provide this desired static pressure below the return course of conveyor belt 40, bottom wall 28 of duct 24 is extended at 28A to pro'- vide a surface against which the air passing through the lower or return course of the conveyor belt can impinge.

The flexible sealing members 58 of the mechanical sealing assembly functions to minimize air leakage in the areas across the width of duct 24 which from time to time does not have the benefit of the static fluid pressure -seal because of packages which block flow of air` the conveyor belt.

While the apparatus is shown with the ends of two

conveyors

34 and 36 projecting into duct 24, it is to be understood that the invention is applicable to a` structure wherein a single conveyor extends into and through duct 24 without departure from the scope and spirit of this invention. In addition, while the fluid seal and mechanical seal according to this invention have been shown and described for the lower opening in freezing chamber 10, it is within the purview of the present invention to provide af-lblower 66 adjacent the upper opening within the freezing chamber, as shown in broken lines in FIGS. 1 and 2, and cooperatively associated with the novel mechanical seal assembly similar to that described for the lower opening. This blower 66 provides a static pressure withinA the freezing chamber to prevent ambient air from being sucked through the opening into the chamber.

Although but one embodiment of the invention has been illustrated and described in detail, it s to be expressz in the art.

present invention includes an air blower 66 arranged to i cooperate with the flexible walls 50 and 58 of the mechanical sealing assembly and belt 40 to reduce air leakage through duct 24 to a negligible amount over a wide variety of shapes and sizes of material being conveyed through the ducts and a wide range of load on the conveyors.

As best shown in FIGS. 3, 4, 5 and 6, the blower 66 comprises a housing 68 in which Ia motor 70 is mounted to drive two impellers or fans '72 mounted on the rotor of the motor. Each of the fans 72 is disposed adjacent a screened inlet port 74 in the opposite end walls of housing 68 to draw ambient air into the housing and discharge the same through an elongated, discharge port 76 in the bottom of housing 68. The entire blower assembly is secured to wall 14 of freezing chamber l@ by means of a plurality of spaced mounting bolts 78 so that the discharge port 76 in housing 68 is disposed above and adjacent duct 24. The discharge port 76 may be provided with guide vanes 80 to distribute and direct the air discharge downwardly and substantially normal to conveyor belt 40. The capacity of blower 66 may be regulated by angular adjustment of the slotted discs 82 relative to each other, which discs are mounted in each inlet port 72.

Since the construction of the blower forms no part of the invention, any blower capable of discharging a continuous stream of air across the entire width of Aconveyor belt 40 and substantially normal to the latter will be applicable t-o the present invention without departing from the scope and spirit of the present invention. One such blower applicable to this invention is disclosed in the U.S. patent to Morrison, No. 3,145,641.

What is claimed is:

1. In a freezing chamber defined by wall means having at least one opening in said wall means communicating the chamber with the ambient atmosphere' and having a foraminous conveyor. extending into said opening to transport material through the opening; the combination of a mechanical seal means comprising, a plurality of spaced flexible ,walls disposed within the opening and engaging the conveyor and said material transported by the conveyorto provide atleast a partial sealing of-the opening, and a fluid seal means comprising blowermeans for discharging a stream of gaseous fluid across said opening so as to impinge said conveyor and the material on said conveyor andthereby create a static fluid pressure adjacent said opening to prevent passage of air through the opening, and a baille means disposed adjacent said opening on the side of the foraminous conveyor opposite from the blower lmeans and projecting from the chamber wall means so that the fluid stream passing through the foraminous conveyor impinges thereon to create a fluid static pressure adjacent the opening on the side of the conveyor opposite from the blower means.

2. In a freezing chamber having at least one opening disposed in one of the walls defining the freezing chamber and a foraminous conveyor extending through the opening for transporting material through the opening, the combination of a mechanical seal means comprising a plurality of spaced flexible walls disposed within each of the openings and engaging the conveyor and the material carried on the conveyor to provide at least a partial seal as the material is transported through the opening, a blower disposed adjacent the opening and exteriorly of the wall to discharge a continuous stream of air across the opening and in impingement against the conveyor and the material carried on the conveyor to thereby-provide a static pressure adjacent the opening above the belt substantially equal to the pressure in the freezing chamber adjacent the opening and prevent the passage of air from inside the chamber to the ambient atmosphere through the opening, and means disposed below said conveyor and in the path of the air stream against which the latter impinges to provide a static pressure across the opening and below the conveyor substantially equal to the pressure of the air within the freezing chamber adjacent said open- 3. Thelapparatus of claim 2 wherein each of the llexible walls comprises two rows of a plurality of adjacent fingers with the fingers in one row offset from the ngers of the other rowso that one row of fingers covers the space between the fingers of the other row.

4. Therapparatus of claim 2 wherein said blower has an elongated, relatively narrow air discharge outlet.

5. The apparatus of claim 2 wherein said impinging means comprises a projecting member which forms part of a lining of the opening in the freezing chamber wall.

6. A mechanical seal assembly for an opening in a wall of a plurality of walls forming a chamber and through which opening an endless foraminous conveyor belt means extends to carry material through the opening, said assembly comprising a plurality of spaced first flexible walls depending from the top wall of the opening and engaging at their distal ends the top of the conveyor means, a plurality of spaced second flexible walls projecting from the bottom wall of said opening and engaging at the distal ends thereof the underside of said conveyor means, each of said first walls comprising a plurality of adjacent ilexible sheets, each of the flexible sheets having a plurality of parallel slits to form fingers capable of independent ilexure, each of the ilexible sheets being disposed in abutting s ide by side relationship with the lingers of one sheet offset from the fingers of the next adjacent sheet.

7. In a freezing chamber having at least one opening in a wall defining said chamber and a foraminous conveyor extending into said opening to transport material through the opening, a sealing means for said opening comprising a fluid seal means secured to said wall for discharging a stream of gaseous tluid across said opening so as to impinge said conveyor and the material on said conveyor and thereby create a static fluid pressure adjacent said opening, and a baille means adjacent said opening on the side of the conveyor opposite from the fluid seal means and projecting from said chamber wall so that the gaseous fluid stream passing through the conveyor impinges thereon to create a fluid static pressure adjacent the opening on the side of said conveyor opposite from the fluid seal means.

8. A mechanical fluid seal assembly for an opening in a wall of a plurality of walls defining a chamber and through which opening a conveyor means extends to carry material through the opening, said assembly comprising a plurality of spaced first flexible walls depending from the top wall of the opening and engaging at their distal ends the top of the conveyor means and a plurality of spaced second ilexible walls projecting from the bottom wall of said opening to engage the underside of the conveyor means, each of said first and second ilexible walls comprising a flexible sheet having a plurality of spaced slits extending from the distal end to a point in spaced relationship with the opposite end to thereby form a plurality of llexible fingers, and each of said irst walls comprises a plurality of ilexible sheets, each of the flexible sheets being provided with a plurality of spaced sheets extending from the distal end thereof to a point spaced from the opposite end to thereby form ya plurality of flexible ngers, each of said plurality of flexible sheets being disposed side by side with the fingers of one sheet being offset from the fingers of the next adjacent sheet.

References Cited by the Examiner UNITED STATES PATENTS 1,361,977 12/1920 Fuller 263-50 2,300,229 10/1942 Knowles 62-380 X 2,620,573 12/1952 McMahon 34-242 X 3,114,248 12/1963 Morrison 62`380 X 3,200,776 8/1965 Simpson 263-50 X 3,255,608 6/1966 Macintosh 62-380 X ROBERT A. OLEARY, Primary Examiner.

MEYER PERLIN, Examiner.

W. E. WAYNER, Assistant Examiner.

Claims

1. IN A FREEZING CHAMBER DEFINED BY WALL MEANS HAVING AT LEAST ONE OPENING IN SAID WALL MEANS COMMUNICATING THE CHAMBER WITH THE AMBIENT ATMOSPHERE AND HAVING A FORAMINOUS CONVEYOR EXTENDING INTO SAID OPENING TO TRANSPORT MATERIAL THROUGH THE OPENING; THE COMBINATION OF A MECHANICAL SEAL MEANS COMPRISING, A PLURALITY OF SPACED FLEXIBLE WALLS DISPOSED WITHIN THE OPENING AND ENGAGING THE CONVEYOR AND SAID MATERIAL TRANSPORTED BY THE CONVEYOR TO PROVIDE AT LEAST A PARTIAL SEALING OF THE OPENING, AND A FLUID SEAL MEANS COMPRISING BLOWER MEANS FOR DISCHARGING A STREAM OF GASEOUS FLUID ACROSS SAID OPENING SO AS TO IMPINGE SAID CONVEYOR AND THE MATERIAL ON SAID CONVEYOR AND THEREBY CREATE A STATIC FLUID PRESSURE ADJACENT SAID OPENING TO PREVENT PASSAGE OF AIR THROUGH THE OPENING, AND A BAFFLE MEANS DISPOSED ADJACENT SAID OPENING ON THE SIDE OF THE FORAMINOUS CONVEYOR OPPOSITE FROM THE BLOWER MEANS AND PROJECTING FROM THE CHAMBER WALL MEANS SO THAT THE FLUID STREAM PASSING THROUGH THE FORAMINOUS CONVEYOR IMPINGES THEREON TO CREATE A FLUID STATIC PRESSURE ADJACENT THE OPENING ON THE SIDE OF THE CONVEYOR OPPOSITE FROM THE BLOWER MEANS.