Hot melt feed system

Patent metadata

Field	Value
Publication number	US-2024391711-A1
Application number	US-202418668820-A
Country	US
Kind code	A1
Filing date	May 20, 2024
Priority date	May 22, 2023
Publication date	Nov 28, 2024
Grant date	—

Abstract

A hot melt system is configured to generate liquid adhesive from solid adhesive pellets. The liquid adhesive is applied to components, such as box tops, to fix components together. A melter is configured to melt the adhesive pellets into the liquid adhesive. Adhesive pellets are periodically fed from a hopper to the melter to maintain a constant supply of liquid adhesive. An adjustable flow restrictor is disposed upstream of a feeder that displaces the adhesive pellets from the hopper to the melter. The adjustable flow restrictor is adjustable to change a flow of the compressed gas flow to the feeder. Adjusting the flow of the compressed gas flow adjusts the feed rate of the adhesive pellets from the hopper to the melter.

First claim

1 . A hot melt system comprising:
a hopper configured to hold a supply of adhesive pellets; a melter configured to melt the adhesive pellets to form a liquid adhesive; a pump configured to pump the liquid adhesive from the melter; a venturi feed configured to draw the adhesive pellets from the hopper and drive the adhesive pellets to the melter; a feed line configured to provide compressed gas to the venturi feed to operate the venturi feed; and a adjustable flow restrictor disposed on the feed line upstream of the venturi feed, wherein the adjustable flow restrictor is configured to regulate a flow of the compressed gas provided to the venturi feed, and wherein the adjustable flow restrictor is adjustable to change the flow.

2 . The hot melt system of claim 1 , further comprising:
a vibrator connected to the hopper, the vibrator configured to vibrate the hopper to agitate the adhesive pellets.

3 . The hot melt system of claim 2 , wherein the vibrator is fluidly connected to the feed line to receive the compressed gas from the feed line, and wherein the vibrator is pneumatically operated.

4 . The hot melt system of claim 3 , wherein a splitter divides the feed line into a first branch path and a second branch path, the first branch path fluidly connected to the vibrator to provide a first portion of the compressed gas to the vibrator, and the second branch path fluidly connected to the venturi feed to provide a second portion of the compressed gas to the venturi feed.

5 . The hot melt system of claim 4 , further comprising:
a feed valve, the feed valve operable between an open state to allow the compressed gas to flow downstream through the feed valve and a closed state to prevent the compressed gas from flowing downstream through the feed valve; wherein the feed valve is disposed upstream of the splitter.

6 . The hot melt system of claim 4 , wherein the adjustable flow restrictor is disposed on the second branch path downstream of the splitter.

7 . The hot melt system of claim 4 , further comprising:
a first feed valve disposed on the first branch path and operable between a first open state and a first closed state; and a second feed valve disposed on the second branch path and operable between a second open state and a second closed state.

8 . The hot melt system of claim 7 , wherein the adjustable flow restrictor is disposed downstream of the second feed valve.

9 . The hot melt system of claim 7 , further comprising:
a controller configured to cause the first feed valve to open prior to causing the second feed valve to open.

10 . The hot melt system of claim 1 , further comprising:
a controller operatively connected to the adjustable flow restrictor, the controller configured to control opening of the adjustable flow restrictor to control flow of compressed gas to the venturi feed.

11 . The hot melt system of claim 1 , further comprising:
a controller configured to:
determine a target feed rate for feeding the adhesive pellets to the melter;
compare the target feed rate to an actual feed rate of the adhesive pellets; and
generate and output an adjust signal based on the comparison indicating that the actual feed rate does not match the target feed rate, wherein the adjust signal is provided to a user interface to cause the user interface to output an indication regarding mismatch between the actual feed rate and the target feed rate.

12 . The hot melt system of claim 11 , wherein the indication includes an instruction regarding adjustment of the adjustable flow restrictor.

13 . The hot melt system of claim 12 , wherein the instruction includes adjusting the adjustable flow restrictor to increase flow through the venturi feed based on the comparison indicating that the actual feed rate is below the target feed rate.

14 . The hot melt system of claim 12 , wherein the instruction includes adjusting the adjustable flow restrictor to decrease flow through the venturi feed based on the comparison indicating that the actual feed rate is above the target feed rate.

15 . The hot melt system of claim 11 , wherein the target feed rate is a range between an upper range end and a lower range end.

16 . The hot melt system of claim 1 , further comprising:
a controller configured to:
determine a target feed rate for feeding the adhesive pellets to the melter;
compare the target feed rate to an actual feed rate of the adhesive pellets; and
generate and output an adjust signal based on the comparison indicating that the actual feed rate does not match the target feed rate, wherein the adjust signal is provided to the adjustable flow restrictor to actuate the adjustable flow restrictor to adjust flow to the venturi feed.

17 . The hot melt system of claim 1 , further comprising:
a level sensor configured to generate level information regarding a level of adhesive in the melter; and a controller configured to:
open a feed valve disposed upstream of the feed line to cause pneumatic flow to the venturi feed based on the level information indicating the level of adhesive reaching a lower level threshold; and
close the feed valve to stop pneumatic flow to the venturi feed based on the level information indicating the level of adhesive reaching an upper level threshold.

18 . The hot melt system of claim 1 , further comprising:
a controller configured to:
monitor a dispense rate at which adhesive is drawn from the melter; and
adjust a feed frequency at which the adhesive pellets are fed from the hopper to the melter by the venturi feed based on the dispense rate.

19 . A hot melt system comprising:
a hopper configured to hold a supply of adhesive pellets; a melter configured to melt the adhesive pellets to form a liquid adhesive; a pump configured to pump the liquid adhesive from the melter; a vibrator connected to the hopper, the vibrator configured to vibrate the hopper to agitate the adhesive pellets; a venturi feed configured to draw the adhesive pellets from the hopper and drive the adhesive pellets to the melter; a feed line configured to provide compressed gas to the venturi feed to operate the venturi feed; a first feed valve actuatable between an open state and a closed state, the first feed valve disposed upstream of the venturi feed such that the first feed valve allows pneumatic flow to the venturi feed when in the open state and the first feed valve prevents pneumatic flow to the venturi feed when in the closed state; a adjustable flow restrictor disposed on the feed line upstream of the venturi feed, wherein the adjustable flow restrictor is configured to regulate a flow of the compressed gas provided to the venturi feed, and wherein the adjustable flow restrictor is adjustable to change the flow; and a controller configured to:
cause the first feed valve to open to cause the venturi feed to drive the adhesive pellets from the hopper to the melter; and
cause the first feed valve to close to prevent adhesive pellets from being carried to the melter from the hopper.

20 . A method of feeding adhesive pellets within a hot melt system, the method comprising:
receiving, at a controller, a call for additional adhesive pellets to be fed to a melter, the melter configured to melt the adhesive pellets into a liquid adhesive; opening, by the controller, a first feed valve to allow compressed gas to flow downstream through a feed line to a venturi feed, the compressed gas through the venturi feed picking up the adhesive pellets from within a hopper

Assignees

• Graco Minnesota Inc

Inventors

• Friedrich Adam R
• Mcgonnell John A

Classifications

• B65G53/66

  Use of indicator or control devices, e.g. for controlling gas pressure, for controlling proportions of material and gas, for indicating or preventing jamming of material {(controlling the flow of coal firing systems C21B5/003)} · CPC title

• B05C11/1042

  provided with means for heating or cooling the liquid or other fluent material in the supplying means upstream of the applying apparatus · CPC title

• B65G53/26 Primary

  operating with fluidisation of the materials · CPC title

• B05C11/1026 Primary

  Valves (in general F16K; B05C5/0225 takes precedence) · CPC title