US3580644A

US3580644A - Pneumatic feed system for uniform supply of tobacco to cigarette making machines

Info

Publication number: US3580644A
Application number: US804071A
Authority: US
Inventors: Francis J Ballard Jr
Original assignee: Brown and Williamson Tobacco Corp
Current assignee: Brown and Williamson Holdings Inc
Priority date: 1969-03-04
Filing date: 1969-03-04
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25

Abstract

A tobacco discharger associated with a cigarette making machine and an automatic tobacco conveying system for pneumatically conveying tobacco from a storage area to the cigarette machine wherein the conveying system includes a main feed pipe coupled with the source of the stored tobacco and the discharger, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for feeding the tobacco into the main feed pipe, and air pressure sensitive means for sensing the air pressure in the main pipe and actuating the operation of the feeder upon attainment of the predetermined conveying velocity of the air to the discharger. The discharger includes a housing having an air inlet end coupled with the main feed pipe and an air discharge end. It also contains tobacco separating means within the housing for separating tobacco carried by air entering the inlet end so that the separated tobacco is uniformly distributed within the housing. Means are also included for causing the uniformly separated tobacco to be discharged into the cigarette making machine in a constantly uniform manner due to the uniform positioning of the separated tobacco within the housing.

Description

United States Patent Primary Examiner-Andres I-I. Nielsen Attorney-Kane, Dalsimer, Kane, Sullivan and Kurucz 2-11 Appl. No.

Filed Mar. 4, 1969 ABSTRACT: A tobacco discharger associated with a cigarette [45] Patented May25,l971

Assignee making machine and an automatic tobacco conveying system Brown & Williamson Tobacco Corporation Louisville, Ky.

for pneumatically conveying tobacco from a storage area to the cigarette machine wherein the conveying system includes a main feed pipe coupled with the source of the stored tobacco and the discharger, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for [54] PNEUMATIC FEED SYSTEM FOR UNIFORM f SUPPLY OF TOBACCO To CIGARETTE MAKING ceding the tobacco into the main feed pipe, and air pressure MACHINES sensitive means for sensing the air pressure in the main pipe 2 Claims, 2 Drawing Figs and actuating the operation of the feeder upon attainment of [52] U 8 Cl the predetermined conveying velocity of the air to the discharger. The discharger includes a housing having an air inlet end coupled with the main feed pipe and an air discharge end. It also contains tobacco separating means within the housing for separating tobacco carried by air entering the inlet [50] Field of end so that the separated tobacco is uniformly distributed within the housing. Means are also included for causing the uniformly separated tobacco to be discharged into the cigarette making machine in a constantly uniform manner due 302/59 to the uniform positioning of the separated tobacco within the 302/28 housing.

Smm mm Nn" mm Tn" mm Pu mh ASd T w m D WGB mm 99 n 06 03 47 36 38 3 PNEUMATIC FEED SYSTEM FOR UNIFORM SUPPLY OF TOBACCO TO CIGARETTE MAKING MACHINES CROSS REFERENCE TO RELATED APPLICATIONS Reference is made to my previous U.S. Pat. No. 3,386,773 issued on June 4, 1968 for Pneumatic Feed System For Cigarette Making Machines, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Initially it should be noted that the above mentioned patent provided a significant contribution to the art of cigarette manufacturing by providing a significantly improved pneumatic feed system for cigarette making machines. Naturally as the art advances further developments are made in this area and it is a further improvement for use with a system of the type described in the above patent with which this disclosure is concerned.

It has been observed in certain instances where a pneumatic feed system in accordance with the above patent is being used that, even though the differential pressure sensing device was properly adjusted and the discharger units were filling properly, there existed a definite tendency for the making machine hopper to fill unevenly. This unevenness followed a very definite pattern with the underfill always occurring on the side of the hopper beneath the tobacco and air combination inlet side of the discharger. Study of this phenomenon has revealed that this is a function of the system itself even though everything is adjusted properly. To retrogress a moment, to properly understand and explain this uneven filling, one must first understand the manner in which a discharger separates the tobacco from the air stream and the manner in which the separating chamber fills. When the suction valve opens, air drawn through the discharger first closes the discharger door and then starts drawing air through the feed pipe. When conveying velocity is reached, the tobacco feeder starts and tobacco is fed into the system. The first tobacco, separated by the screen and air currents in the discharger, is deposited in the lower comer of the separating chamber on the side beneath the air discharge. The filling then proceeds at approximately a 45 angle toward the feed end of the discharger. When the differential pressure sensing unit stops the cell on the system, the chamber is approximately 95 percent full. To fill this last 5 percent of the chamber, the probability of blocking the check valve becomes a problem. Therefore it is preferable not to even attempt to completely fill the chamber.

The 5 percent empty area coupled with the compressive packing of the first tobacco separated, caused by the air velocity and weight of the material as it is progressively deposited across the width of the discharger, are the factors causing the uneven hopper filling beneath the tobacco and air inlet end of the discharger. Due to the manner in which the making machine feeds cut tobacco from the hopper onto the cigarette forming feed belt, a nonuniformity in the hopper level causes a periodic noncontrollable low density spot in the continuous cigarette rod formed on the machine. This light spot is then sensed by the weight controls on the machine causing them to put out a correction for something that it cannot correct and thereby possibly further upsetting the weight control of the machine. Thisall contributes to a greater nonuniformity in the cigarette weights which are a quality concern. Therefore, although the system of the above patent has provided a great contribution to the art, to compensate for this additional newly discovered problem, it would be helpful if a means could be provided in the system for alleviating this particular drawback.

SUMMARY OF THE INVENTION ing area from the air discharge side to the tobacco and air inlet side. The sloping of the screen has greatly increased the uniformity of the feed roll in the making machine hopper and eliminated the uneven filling on a properly adjusted system.

In summary, the general concept embodied in this invention is to provide an improved tobacco discharger associated with a cigarette making machine and an automatic tobacco conveying system for pneumatically conveying tobacco from a storage area to the cigarette machine wherein the conveying system includes a main feed pipe coupled with the source of the stored tobacco and the discharger, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for feeding the tobacco into the main feed pipe, and air pressure sensitive means for sensing the air pressure in the main pipe and actuating the operation of the feeder upon attainment of the predetermined conveying velocity of the air to the discharger. The discharger includes a housing having an air inlet end coupled with the main feed pipe and an air discharge end. It also contains tobacco separating means within the housing for separating tobacco carried by air entering the inlet end so that the separated tobacco is uniformly distributed within the housing. Means are also included for causing the uniformly separated tobacco to be discharged into the cigarette making machine in a constantly uniform manner due to the uniform positioning of the separated tobacco within the housing.

With the above and other objects in mind, reference is had to the attached drawing of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a longitudinal sectional view of the novel tobacco separator of the system for pneumatically conveying cut tobacco from a storage area to a cigarette making machine of this invention associated with the hopper of a cigarette making machine; and

FIG. 2 is a sectional view thereof taken along the line 2-2 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT So that the structure and operation of the majority of the system is identical to that of the above referenced patent application, a detailed picture of the common elements is not necessary nor is it necessary to include a detailed description of these elements. The difference in structure lies in the tobacco discharger portion of the system and it is that portion which is depicted in FIGS. 1 and 2 and which will be described in detail below.

However, to put the tobacco discharger in its proper environment, a general overall .description of the system will be included herein to orient that reader as to the particular location and function of the unique subject matter within the overall system as particularly defined in the above referenced patent. The overall purpose of the pneumatic system of the invention is to convey cut tobacco from the cut tobacco storage areas to the making machines automatically, as required by the making machines. A sensing device in each making machine hopper operates to detect a low level of tobacco to initiate the prescribed series of events. The system is designed to feed only one of a given number of making machines at a time upon request for cut tobacco.

When a request is made by a particular cigarette making machine, a control unit operates to select the proper making machine and opens the suction side of a separator incorporating the teachings of the present invention, located at the top of the selected making machine hopper. At the same time, the control unit initiates a cycle timing device. Thereafter, a trapped door on the tobacco separator is drawn closed and check valves on all of the other separators in the system are closed and drawn into their respective seats by the suction valve present in the tobacco feed pipe. Air flow is now established in the system from the cut tobacco to the exhaust of the suction producing device through the selected separator of the making machine requiring tobacco.

When the air flow in the feed pipe or duct reaches the prescribed conveying velocity, a differential pressure switch located in proximity of the feeder senses this condition and causes the feeder to be energized independently and without any connection to the balance of the system other than the feed pipe. Tobacco flow is now established between the storage area and the selected making machine. At the particular separator, the tobacco is separated from the air stream by means of a screen installed between the inlet and discharge and of the separator.

As the air conveyed cut tobacco fills the separator, the pressure drop across the separator progressively increases. When this pressure drop reaches a preset level or value, the control unit closes the suction side of the separator. The desired amount of cut tobacco collected on the separator screen is correlated to pressure drop to thereby assure the optimum amount of tobacco to be loaded into the selected cigarette making hopper, with the cycle timing device operating to serve as a safety factor in preventing overloading of the separator.

The loss of conveying velocity in the feed pipe will now be sensed by the differential pressure switch located near the feeder to thereby cause deenergization of 'the feeder. The trapped door of the separator will now swing open under the influence of gravity and the collected cut tobacco falls into the selected making machine hopper. When this occurs, the low level circuit on the making machine is deenergized. Provision is made in the control unit to prevent an immediate recall on a maker before the tobacco drops into the hopper in the event there is no other maker with a low level indicated.

Also contemplated is a control unit set up either on a random memory network or a sequential demand network. In any event, the master control unit is at rest when no maker is showing a low level.

In addition, controlled air bleeds are incorporated into the feed line of the last maker located on the feed line to prevent an accumulation type buildup which eventually might cause a stop-up in the system. A controlled air bleed in the suction line 1 of the blower is used in systems where multiple feed systems are taken off a single blower. This air bleed is controlled by the motor load to prevent the blower from pulsating on no load conditions by bleeding air into the system and from overloading on full load conditions by closing off the air bleed.

In addition to the above general reiteration of the improved system for conveying cut tobacco from a storage area to a cigarette making machine as defined particularly in the above referenced patent, details of the cut tobacco separator associated with each making machine hopper are of a novel and improved nature which will be disclosed in considerable detail as follows. Referring now to the particular details of the novel separator 20, the separator is advantageously mounted over the hopper 21 of a cigarette making machine only fragmentarily shown in the drawings. This machine may assume the form of any one of a number of commercially available cigarette making machines. When necessary, hopper 21 of commercial equipment may require that its capacity be decreased. Be that as it may, hopper 21 includes Sonac relay sensors (not shown) or other suitable means for responding to the level of tobacco in the hopper to register the call or request for tobacco from the pneumatic conveying system of the invention. When this occurs, cut tobacco will eventually enter the separator 20 through the check valve 22 and fill the compartment 23 immediately below the separating screen 24 with the air stream passing on through the open suction valve 25. When the compartment 23 is nearly full, screen 24 is very nearly blocked thereby causing a relatively high differential pressure across the screen. Advantage is taken of the develop-' ment of this pressure drop by employing a differential pressure switch 26 communicating with both the upstream and downstream side of the separator and across screen 26. Upon the attainment of the desired predetermined pressure drop or pressure differential, switch 26 is actuated to cause the suction valve 25 to be closed. Subsequently, the trap or discharge door 27 at the base of separator 20 will open and release the accumulated tobacco into the cigarette making machine hopper 21. The check valve 22, in accordance with a success ful and somewhat preferred embodiment of the invention, embodies a soft, tough, resilient material contained between a pair of metal discs. The small disc is merely a retainer for holding the larger outer discs. In the closed position, valve 22 is sucked into the inlet end 28 of the feed pipe and will close and seal over any particles of tobacco that may be found on the valve seat, thereby preventing any backfl ow air leakage. The suction valve 25 is shifted from a fully opened to fully closed position by means of a piston cylinder 29. Cylinder 29 operates preferably off a four-way solenoid air valve (not shown).

Particular attention should be paid to separator screen 24 which is sloped upwardly in location in separator 20. The lower side of screen 24 is adjacent the discharge passage of the separator and the upper side of screen 24 is adjacent the inlet passage. As previously described in detail, this is necessary in order to achieve a particular uniform distribution of tobacco within the separator 20 which is later to be discharged through discharge door 74 into the cigarette making machine. This positioning of screen 24 is advantageous due to the tendency for the separator to fill unevenly. This is true even though the differential pressure sensing device is properly adjusted and the discharging unit is filling properly. With a horizontal screen, the uneveness will follow a very definite pattern with the underfill always occurring on the side of the hopper beneath the tobacco and air inlet side of the separator 20.

As previously discussed, observation of this phenomenon has revealed that this will occur with a horizontal screen even though everything is adjusted properly. To explain this uneven filling, one must first understand the manner in which a discharger separates the tobacco from the air stream and the manner in which the separating chamber fills. When the suction valve 25 opens, air drawn through the discharge first closes the discharge door 27 and then starts drawing air through the feed pipe. When conveying velocity is reached, the tobacco feeder starts and tobacco is fed into the system. The first tobacco, separated by a horizontal type of screen and air currents in the separator, is deposited in the lower corner of the separating chamber on the side beneath the air discharge. The filling then proceeds at approximately a 45 angle toward the feed end of the separator. When the differential pressure sensing unit stops the call on the system, the chamber is approximately percent full. To fill this last 5 percent of the chamber, the probability of blocking the check valve 22 becomes a problem. Therefore, it is generally not ever attempted to completely fill the chamber.

The 5 percent empty area coupled with the compressive packing of the first tobacco separated, caused by the air velocity and weight of the material as it is progressively deposited across the width of the separator, are factors contributing to the uneven hopper filling beneath the tobacco and air inlet ends 76 of the separator 20. Due to the manner in which the making machine feeds cut tobacco from the hopper onto the cigarette forming feed belt, a nonuniformity in the hopper level causes a periodic noncontrollable low density spot and the continuous cigarette rod formed on the machine. This light spot is then sensed by the weight controls on the machine causing them to put out a correction for something that it cannot correct and thereby further upsetting the weight control of the machine. This all contributes to a greater nonuniformity in cigarette weights which are a major quality concern. To compensate for this, separating screen 24 in separator 20 has been raised on the inlet side. This provides a progressively increasing area from the air discharge side to the tobacco and air inlet side.

Thus, sloping of screen 24 has greatly increased the uniformity of the feed roll in the making machine hopper and has virtually eliminated the occurrence of uneven filling on a properly adjusted system.

Thus, the above mentioned objects of the invention, among others, are achieved.

lclaim:

1. An automatic tobacco conveying system for pneumatically conveying tobacco from a storage area to at least one cigarette making machine, said system including a main feed pipe coupled with the source of the stored tobacco and the cigarette making machine, a tobacco discharger associated with said cigarette making machine and having a housing with an inlet coupled with the main feed pipe and an air discharge end and means for causing the separated tobacco to be discharged into the cigarette making machine, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for feeding the tobacco into the main feed pipe, and air pressure sensitive means for sensing the air pressure in the main pipe and actuating the operation of the feeder upon attainment of the predetermined conveying velocity of the air to the cigarette making machine, the improvement comprising: tobacco separating means within the housing for separating tobacco carried by air entering the inlet in a uniform manner so that the separated tobacco is distributed uniformly within the housing so that when the separated tobacco is discharged into the cigarette making machine it will be discharged in a uniform manner, said tobacco separating means in said housing including a tobacco separating screen arranged within the housing intermediate the inlet and discharge ends which are located on opposing sides of the housing for separating tobacco carried by air entering the inlet end, said separating screen being sloped angularly upward from the discharge end side of the housing toward the inlet end side of the housing thereby providing a progressively increasing area beneath the screen within the housing from the air discharge side to the air inlet side to assist in providing uniform discharge of the tobacco into the cigarette making machine.

2. A tobacco discharger associated with a cigarette making machine and an automatic tobacco conveying system for pneumatically conveying tobacco from a storage area to the cigarette making machine with the system including a main feed pipe coupled with the source of the stored tobacco and the tobacco discharger, air differential pressure means for forcing air through the pipe at a predetermined conveying velocity, a tobacco feeder at the source of stored tobacco for feeding the tobacco into the main feed pipe, air pressure sensitive means for sensing the air pressure in the main pipe and actuating the operation of the feeder upon attainment of the predetermined conveying velocity of the air to the tobacco discharger comprising; a housing having an air inlet and coupled with the main feed pipe and an air discharge end, tobacco separating means within the housing for separating tobacco carried by air entering the inlet end in a manner which distributes the tobacco within the housing in a uniform manner, and means for causing the uniformly distributed separated tobacco to be discharged into the cigarette making machine in a manner which greatly alleviates the danger of uneven filling during the following cigarette making process, the tobacco separating means including a tobacco separating screen arranged within the housing intermediate the inlet and discharge ends which are located on opposing sides of the housing for separating tobacco carried by air entering the inlet end, said screen sloping upwardly from adjacent the discharge end of the housing toward the inlet end of the housing thereby uniformly separating and distributing tobacco carried by air entering the inlet end within the housing to greatly increase the uniformity of the separated tobacco within the housing to be discharged into the cigarette making machine.