Gas flushing system for vertical form, fill and seal machines

Claim 2

In combination with a bag forming, filling and sealing machine including a vertical tube having communicating therewith product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube and operative to discharge flushing gas into the tube for purging atmospheric oxygen from product supplied through the tube into bags formed below said discharge end; means for supplying said nozzle with flushing gas through the wall area of said tube between said head structure and said folding means; a gas sampling duct having an inlet end extending below said discharge end of the tube to be effective within the next formed bag under said discharge end; a suction line connected to said duct above said forming means including a valve; and means connecting said valve with flushing gas supply for alternatively supplying gas into the next filled bag or for withdrawing a gas sample from such bag, under the control of said valve.

Claim 3

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: means for supplying flushing gas adjacent to the lower end of said passage including a nozzle and a duct leading thereto; means for supplying flushing gas; gas monitoring means; and means for alternatively connecting said duct with said gas supplying means and with said monitoring means.

Claim 4

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: means for supplying flushing gas adjacent to the lower end of said passage including a nozzle and a duct leading thereto; means for supplying flushing gas; gas monitoring means; and means for alternatively connecting said duct with said gas supplying means and with said monitoring means.

Claim 5

A combination according to claim 2, said means for connecting being also operative to open said duct to atmosphere.

Claim 6

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and having a number of distribution holes along its length within said passage operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product as the product moves down through the passage and before the product drops from the discharge end into the bags that have been formed below said discharge end; and means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means including a gas source and supply line duct means connecting the source with said nozzle and having therein a shut-off valve adapted to be controlled in coordinated relation with the machine, and flow-controlling means as well as pressure-regulating means and flow-metering means in said line duct means downstream from said valve.

Claim 7

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and having a number of distribution holes along its length within said passage operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product as the product moves down through the passage and before the product drops from the discharge end into the bags that have been formed below said discharge end; and means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means including a gas source and supply line duct means connecting the source with said nozzle and having therein a shut-off valve adapted to be controlled in coordinated relation with the machine, and flow-controlling means as well as pressure-regulating means and flow-metering means in said line duct means downstream from said valve.

Claim 8

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas meanS communicating with an upper portion of the tube passage; a gas sampling duct having an inlet end extending below said discharge end; and a suction line connected to said duct above said forming means.

Claim 9

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas meanS communicating with an upper portion of the tube passage; a gas sampling duct having an inlet end extending below said discharge end; and a suction line connected to said duct above said forming means.

Claim 10

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from the product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas means communicating with an upper portion of the tube passage; a combination prepurge and gas sampling duct having a discharge inlet end extending below said discharge end of the tube to be effective within the next formed bag under said discharge end; and means for alternatively connecting said duct with said means for supplying gas and with a suction line.

Claim 11

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from the product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas means communicating with an upper portion of the tube passage; a combination prepurge and gas sampling duct having a discharge inlet end extending below said discharge end of the tube to be effective within the next formed bag under said discharge end; and means for alternatively connecting said duct with said means for supplying gas and with a suction line.

Claim 12

A combination according to claim 6, including a filter on and across said inlet end of the duct.

Claim 13

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas means communicating with an upper portion of the tube passage; an initial purging gas supply line communicating with the upper end portion of said tube passage below said head means; and a combination prepurging and gas sampling duct communicating with the next formed bag below said discharge end.

Claim 14

In combination with a bag forming, filling and sealing machine including a vertical tube having a product passage therein communicating with product receiving head means, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the lower discharge end of the tube: an elongated nozzle member extending downwardly within said tube passage and operative to discharge flushing gas into the tube passage for purging atmospheric oxygen from product supplied through the tube passage into bags formed below said discharge end; means for supplying said nozzle member with flushing gas through the wall area of said tube between said head means and said folding means; initial purge gas means communicating with an upper portion of the tube passage; an initial purging gas supply line communicating with the upper end portion of said tube passage below said head means; and a combination prepurging and gas sampling duct communicating with the next formed bag below said discharge end.

Claim 15

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means located near the discharge end of said passage for supplying initial purging gas; and means for effecting withdrawal through said additional means of atmosphere monitoring samples of the atmosphere adjacent to the discharge end of said passage.

Claim 16

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means located near the discharge end of said passage for supplying initial purging gas; and means for effecting withdrawal through said additional means of atmosphere monitoring samples of the atmosphere adjacent to the discharge end of said passage.

Claim 17

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing mEans cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means located near said product entry end of the tube for supplying initial purging gas; and yet additional means are operative to introduce preflushing gas near said discharge end of the passage.

Claim 18

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing mEans cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means located near said product entry end of the tube for supplying initial purging gas; and yet additional means are operative to introduce preflushing gas near said discharge end of the passage.

Claim 19

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means for supplying initial purging gas at a position near one of said tube ends; and means alternatively operable to secure a sample of gas for analysis adjacent to the discharge end of said passage and to introduce preflushing gas.

Claim 20

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means for supplying initial purging gas at a position near one of said tube ends; and means alternatively operable to secure a sample of gas for analysis adjacent to the discharge end of said passage and to introduce preflushing gas.

Claim 21

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means for supplying initial purging gas at a position near one of said tube ends; control valve means for disconnecting said additional means from purging gas supply; and gas analyzing means including a suction pump alternatively connectable with said additional means by operation of said control valve means.

Claim 22

In combination with a bag forming, filling and sealing machine including a vertical tube having an upper entry end and a lower discharge end and a product passage therein with the entry end thereof communicating with head means for delivering product to be bagged into the passage, means spaced below said head means for forming bag sheet material about the tube, seam sealing means cooperative with the tube below the forming means, and combination bag sealing, cut-off and pull-down means operative below the discharge end of the passage: means entering the tube from adjacent to said entry end for supplying product-flushing gas into said tube passage; additional means for supplying initial purging gas at a position near one of said tube ends; control valve means for disconnecting said additional means from purging gas supply; and gas analyzing means including a suction pump alternatively connectable with said additional means by operation of said control valve means.