US3870070A

US3870070A - Air system control

Info

Publication number: US3870070A
Authority: US
Inventors: Gerald A Kraft
Original assignee: Philip Morris USA Inc
Current assignee: Philip Morris USA Inc
Priority date: 1974-01-31
Filing date: 1974-01-31
Publication date: 1975-03-11
Anticipated expiration: 1992-03-11

Abstract

There is disclosed improvements in an exhaust system wherein the tip end of a branch exhaust duct makes juncture with a transition duct leading to a main exhaust duct is provided with a sleeve which collapses in the absence of air flow through the branch to permit a compensating flow of outside air to be drawn into the transition duct around the periphery of the collapsed duct.

Description

United States Patent 11 1 1111 3,870,070

Kraft Mar. 11, 1975 AIR SYSTEM CONTROL 1,633,189 6/1927 P611161 137/526 x 2,812,061 11/1957 Pfister 294/64 R X [75] Inventor: Gerald R'chmondi 3,200,765 8/1965 Amb1i 98/43 PS x 73 Assignee; Philip Morris Incorporated New 3,509,911 5/1970 Carsey 137/602 York, NY. 3,830,241 8/1974 Dye 137/526 x [22] Filed: 1974 Primary Examiner-Robert G. Nilson [21] N 43 403 Attorney, Agent, or Firm-Watson Leavenworth Kelton & Taggart [52] U.S. Cl. 137/512, 98/43 PS, 131/23 R,

137/526, 302/27, 417/306 [57] ABSTRACT [51] Int. Cl. Fl6k 15/14 There is disclosed impro ments in an exhaust system [58] Field of Sear h 55/419, 420; 98/43, 43 R, wherein the tip end of a branch exhaust duct makes 98/43 PS, 116, DIG, 7; 104/52; 137/512, juncture with a transition duct leading to a main ex- 526, 602, 525; 294/64 R, 64 A, 64 B; haust duct is provided with a sleeve which collapses in 417/306; 302/27, 39, 40; 131/23 R, 110 the absence of air flow through the branch to permit a compensating flow of outside air to be drawn into the [56] Reference Cit d transition duct around the periphery of the collapsed UNITED STATES PATENTS duct 1,552,316 9/1925 Krieg 302/27 5 Claims, 4 Drawing Figures CIGARETTE MAKER WITH BLOWER 1 AIR SYSTEM CONTROL BACKGROUND or THE INVENTION The operation of certain manufacturing machinery requires that an exhaust flow of air be drawn through such machinery principally to remove any residue generated during the manufacturing operation and prevent settlement of matter such as dust in the machinery which could affect or impair proper machine functioning. To that end, it is common to provide each operating machine or device, in the case where plural devices are being operated, with its own exhausting means or blower, the output from such blower being delivered through a branch exhaust duct associated with the device to a main exhaust duct. The main exhaust duct also is provided with exhausting means or a fan which is designed to have an operating capacity greater than the sum total capacity of the individual device blower units exhaust delivery to the main exhaust duct, with the system further being designed such that a constant volume and velocity exhaust flow is maintained in the main exhaust duct. Maintenance of constant volume and velocity of exhaust flow in the main exhaust duct is desirable for two reasons:

I. to prevent a drop in exhaust flow volume and velocity as might allow dust to settle in the system and plug the same 2. a drop in volume of air admitted into the system could cause overloading of the main exhaust duct fan unit.

To insure that a full volume of air can flow through the main exhaust duct, the branch exhaust duct of each operating device generally makes exhaust delivery thereto through a transition duct, the juncture of each such branch exhaust duct with the associated transition duct being such that an end of the branch exhaust duct is received in an enlarged skirt at a tip end of the transition duct. This arrangement is such that only a certain portion of skirt enclosed cross-sectional area of the transitional duct is occupied by the end of the branch exhaust duct. Thus a compensating air flow from the environment external to the branch exhaust duct can be drawn into the transition duct, and hence the main exhaust duct, from around the periphery of the branch exhaust duc t.

If an operating device is required to be shut down and thus no exhaust therefrom is being delivered into the main exhaust by its blower, it is necessary to increase the air inlet size to the main exhaust duct from the. external environment in order to maintain the volume demand of the system constant. In order to accomplish this change in external environment air inlet area, there is usually provided a damper in the transition duct which must be adjusted toward greater volume at the time of shutdown of the corresponding blower, or toward less volume at blower start-up. In the past this has customarily been done manually, although it could be accomplished by automatic controls coupled with suitably designed sensors, e.g., located in the blower ducts or the like. However, this control arrangement would be expensive and space-consuming.

One class of operating devices which require continuous exhausting of air and dust therefrom to a central or main exhaust duct are cigarette makers. Operation of these high speed, high capacity devices demands that no dust or like residue settle therein so that maintenance of constant volume and velocity flow conditions in these devices and their main exhaust duct system is highly important.

SUMMARY OF THE INVENTION The present invention has for a purpose the improvement in an air system for exhausting a plurality of operating devices in which the exhaust, for example, air and dust from each individual operating device is delivered to a main exhaust duct which in turn is provided with its own fan unit to maintain a constant volume and velocity exhaust flow in the main exhaust duct. In particular, the inventionis concerned with providing improvements such that if one of the operating devices is closed down so that the absence of exhaust flow therefrom to the main exhaust duct would alter or affect the constant volume and velocity conditions in said main exhaust duct, there will be provided an automatic compensation or inflow of air from the environment external to the particular operating device and its associated branch exhaust duct through the associated transition duct and to the main exhaust duct.

In accordance with the present invention, the foregoing is effected by fitting a flexibly structured sleeve to the tip end of each branch exhaust duct of an operating device where it, the branch exhaust duct, enters the transition duct member associated therewith. The flexibly structured sleeve is provided of a material which is sufficiently flexible as to enlarge radially under the influence of air flow delivered from the blowing means of the operating device through the branch exhaust duct with the sleeve being dimensioned such that in its enlarged condition it occupies only a certain portion of the skirt enclosed cross-sectional area of the transition duct whereby compensating air flow is drawn into the transition duct around the periphery of the sleeve from the environment external to the branch exhaust duct. The sleeve further is sufficiently flexible to collapse from its expanded condition in the absence of air flow through the branch exhaust duct (as when the associated operating device is shut down) thereby to diminish the portion of skirt enclosed cross-sectional area occupied by the sleeve with there thus occurring a concomitant increase in the flow of compensating air drawn into the transition duct and to the main exhaust duct to maintain the flow in the last mentioned component at constant value. v

In accordance with the invention, the sleeve desirably is provided as a relatively thin element that is received exteriorly on and removably secured to the tip end of the associated branch duct. Desirably, the sleeve is secured to the branch exhaust duct with a clamp. The sleeve can be provided such that in its enlarged condition it presents the same configuration as the branch exhaust duct. Thus, if the exhaust duct is cylindrical, the sleeve in enlarged condition can present a hollow cylindrical configuration. When the operating device associated with a particular branch exhaust duct is shut down, the absence of air flow through the branch exhaust duct will result in the sleeve collapsing to permit increased flow of outside environmental air around the sleeve and into the transition duct leading to the main exhaust duct.

The sleeve can be provided from various materials as for example, cotton canvas, rubber and assorted thermoplastic materials.

The invention, accordingly, comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS A fuller understanding of the nature and objects of the present invention will be had from the following detailed description takenin conjunction with the accompanying drawing showing by way of example, a pre ferred embodiment of the inventive concept and in which:

FIG. 1 is a side elevational view of an exhaust system for exhausting a plurality of operating devices and embodying the principles of the present invention.

FIG. 2 is a fragmentary elevational view of the apparatus shown in FIG. 1 depicting the manner in which the branch exhaust duct of one of the operating devices is connected to the main exhaust duct through a transition duct, the rigid duct portion of the branch exhaust duct being fitted with a flexible sleeve in accordance with the present invention, the sleeve being shown in its enlarged position as when there is exhaust flow through the branch exhaust duct.

FIG. 3 is a side view of the flexible sleeve provided by the present invention, the sleeve being shown in its expanded condition.

FIG. 4 is an end view of FIG. 3.

Throughout the following description, like reference numerals are used to denote like parts in the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is concerned with improvements in an exhaust system associated with a plurality of operating devices which require continuous exhausting of air, dust and the like therefrom, with the exhaust of each individual unit being delivered from a blower unit associated with the device through a branch exhaust duct to a main exhaust duct, the main exhaust duct in turn having its own fan unit for drawing air through said main exhaust duct, the operation of the fan unit being such as to maintain constant volume and velocity flow conditions in the main exhaust duct. While the invention herein will be described in terms of its particular applicability to the operation of cigarette making machines, it will be understood that the invention has broader applicability to the problems associated with effecting exhaust from other types of operating devices.

Referring now to FIG. 1 of the drawings, there is depicted a main exhaust duct which is provided with its own exhausting means or fan unit 12 for the purposes of effecting an exhaust flow through the duct 10. Connected with the main exhaust duct 10 are a plurality of transition ducts 14a-14c each of which has associated therewith a respective branch exhaust duct l6a-16c, leading to an individual operating device, e.g., a cigarette maker 18, only one of the lastmentioned devices being depicted for convenience. As will be understood, each cigarette maker 18 is provided with its own exhausting means or blower to effect exhaust of air and dust from the cigarette maker and deliver it through its associated branch duct to the main exhaust duct 10. As will be noted in FIG. 1, each transition duct 14a14c is connected at one end to the main exhaust duct 10 and is provided at its other end with an outwardly flared encircling skirt which encloses a space of predetermined cross-sectional area defining an opening into which a tip end of the associated branch exhaust duct is received in coaxial disposition with the transition duct.

As will be noted in FIGS. 1 and 2, each branch exhaust duct l6a-l6c includes a rigid duct portion which has a tip end as at 24 which terminates spaced a distance from the radial flared skirt on the associated transition duct. Exteriorly on such tip end of the rigid duct portion, there is received a sleeve 22a-22c, with the sleeve being removably secured thereto by any suitable means, as for example by means of a clamp 26. The sleeve is provided as a flexibly structured component of a material sufficiently flexible to enlarge radially under the influence of air flow being delivered through the branch exhaust duct and occupy a certain portion of the transition duct skirt enclosed cross-sectional area. In this fashion when the cigarette maker is being operated, and air being exhausted therefrom for delivery to the main exhaust duct 10, there will occur additionally an intake of air from the environment external to the branch exhaust duct, such air entering around the periphery of the enlarged sleeve and following the entry course generally depicted by the arrows A in FIG. 2. Such additional and compensating air flow is intended to insure that adequate flow of air to the main exhaust duct 10 occurs to keep the volume and velocity of air flow through the main exhaust duct at constant level. This is done inasmuch as the capacity of fan unit 12 is generally greater than the sum total of the capacities of the blower units associated with the individual cigarette makers. As shown in FIG. 2, there may be provided a screen 40 surrounding the juncture of each branch exhaust duct with its associated transition duct.

When it is desired or necessary to shut down one of the operating devices (a cigarette maker) and in consequence thereof change the exhaust flow through the branch exhaust duct associated therewith so that there would otherwise occur a consequent alteration of the flow conditions in the main duct 10, the sleeve fitted to the tip end of the particular branch exhaust duct will collapse in the manner shown with respect to sleeve 22b in FIG. 1. Further in FIG. 2 the collapsed condition of the sleeve is shown in phantom lines as at 30. With the sleeve thus collapsed due to the absence of air flow through the associated branch exhaust duct, there results a diminishing of the portion of skirt enclosed cross-sectional area occupied by the sleeve with a concomitant increase in the flow of compensating air drawn into the transition duct.

FIGS. 3 and 4 depict one form of construction of sleeve in which the sleeve 22 is an assembled structure made from a thin sheet of flexible material, the depicted embodiment being a sheet of material formed such that in its expanded condition it is a hollow cylinder, the sleeve structure being formed by overlapping opposite ends of a sheet of the flexible material and securing such ends together as with adhesive 32. The sleeve 22 can be provided such that its configuration when in expanded condition of course will correspond with that of the rigid portion of the branch exhaust duct to which it is connected. Thus in respect of rectangular shaped ducts, the sleeve desirably will have a corresponding configuration when in its expanded condition, although it need not necessarily be such.

Other materials can be used for making the sleeve. For example, it can be made of soft rubber or of various types of thermoplastic material, as long as the essential properties that it have sufficient flexibility and thinness to collapse in the manner described above is possessed by the structure made therewith.

The present invention can be employed in both new and existing exhaust systems. If an existing system be modified by providing the exhaust branch ducts with sleeves, the dampers 42 commonly found in the transition ducts thereof can be retained although as pointed out earlier, the need for damper position adjustment at shut-down and start-up of the associated operating device is effectively eliminated by the present invention.

While there is disclosed above but one embodiment of air control system improvements according to the present invention, it is possible to produce still other embodiments without departing from the scope of the inventive concept herein disclosed, and accordingly, it should be understood that all matter contained in the above description and the accompanying drawing should be interpreted as illustrative and not in a limited sense.

What is claimed is:

1. ln apparatus for exhausting air and the like from a plurality of operating devices which during operation of the same require continuous removal of air and the like therefrom, which apparatus includes:

a main exhaust duct, and a fan unit for drawing air through said main exhaust duct;

a corresponding plurality of elongated transition ducts each connected at one end to said main exhaust duct and extending a distance therefrom;

an elongated separate branch exhaust duct associated with each device and connected at one end thereof with the associated device and extending therefrom to flow communicative juncture at its other end with the other end of one of said transition ducts, said other end of each transition duct having a radially outwardly flared encircling skirt enclosing a space of predetermined cross-sectional area defining an opening into which the said other end of an associated separate branch exhaust is received in coaxial disposition with said transition duct, there being embodied in each of said devices air blowing means for delivering air flow from each said device to the associated branch exhaust duct,

the improvement in which the said other end of each separate branch exhaust duct is provided as a flexibly structured sleeve of a material sufficiently flexible to enlarge radially under the influence of air flow delivered from the blowing means of said device through said branch exhaust duct and being dimensioned such that in enlarged condition it occupies only a certain portion of the skirt enclosed cross-sectional area whereby compensating air flow can be drawn by the action of said fan unit into said transition duct around the periphery of said sleeve from the environment external to the associated device and branch exhaust duct, said sleeve further being sufficiently flexible to collapse from its expanded condition in the absence of air flow through said branch exhaust duct to diminish the portion of skirt enclosed cross-sectional area occupied by said sleeve with concomitant increase in the flow of compensating air drawn into said transition duct.

2. Apparatus in accordance with claim 1 in which said sleeve is provided as a flexible structure presenting a hollow cylindrical configuration when in enlarged condition.

3. Apparatus in accordance with claim 1 in which each said separate branch exhaust duct includes a rigid duct portion having a tip end terminating spaced a distance from the radial flared skirt on the associated transition duct, the sleeve associated with each said branch exhaust duct being received exteriorly on and removably secured to the tip end of its associated branch duct.

4. Apparatus in accordance with claim 3 in which each sleeve is removably secured to its associated branch duct tip end with a clamp.

5. Apparatus in accordance with claim 1 in which said sleeve is made from one of cotton canvas, rubber and thermoplastic material.

Claims

1. In apparatus for exhausting air and the like from a plurality of operating devices which during operation of the same require continuous removal of air and the like therefrom, which apparatus includEs: a main exhaust duct, and a fan unit for drawing air through said main exhaust duct; a corresponding plurality of elongated transition ducts each connected at one end to said main exhaust duct and extending a distance therefrom; an elongated separate branch exhaust duct associated with each device and connected at one end thereof with the associated device and extending therefrom to flow communicative juncture at its other end with the other end of one of said transition ducts, said other end of each transition duct having a radially outwardly flared encircling skirt enclosing a space of predetermined cross-sectional area defining an opening into which the said other end of an associated separate branch exhaust is received in coaxial disposition with said transition duct, there being embodied in each of said devices air blowing means for delivering air flow from each said device to the associated branch exhaust duct, the improvement in which the said other end of each separate branch exhaust duct is provided as a flexibly structured sleeve of a material sufficiently flexible to enlarge radially under the influence of air flow delivered from the blowing means of said device through said branch exhaust duct and being dimensioned such that in enlarged condition it occupies only a certain portion of the skirt enclosed cross-sectional area whereby compensating air flow can be drawn by the action of said fan unit into said transition duct around the periphery of said sleeve from the environment external to the associated device and branch exhaust duct, said sleeve further being sufficiently flexible to collapse from its expanded condition in the absence of air flow through said branch exhaust duct to diminish the portion of skirt enclosed cross-sectional area occupied by said sleeve with concomitant increase in the flow of compensating air drawn into said transition duct.