Packaging machine for continuously producing sealed packages of a pourable food product, and having a capacitive level sensor

• US 6,684,609 B1
• Filed: 04/11/2000
• Issued: 02/03/2004
• Est. Priority Date: 05/14/1999
• Status: Expired due to Fees

• Current Assignee: Tetra Laval Holdings & Finance SA (Tetra Laval Holdings BV)
• Original Assignee: Tetra Laval Holdings & Finance SA (Tetra Laval Holdings BV)
• Inventors: Galavotti, Giorgio, Bassissi, Fabio
• Primary Examiner(s): Kim, Eugene
• Assistant Examiner(s): HARMON, CHRISTOPHER R
• Application Number:
  US09/546,521
• Time in Patent Office: 1,393 Days
• Field of Search: 535/03, 53/52, 53/55, 53/58, 535/04, 534/51, 534/50
• US Class Current: 53/503
• CPC Class Codes: B65B 37/00 Supplying or feeding fluent-solid, plastic, or liquid material, or loose masses of small articles, to be packaged methods of, or means for, filling individual containers with such materials or articles B65B1/04, B65B3/04
• CPC Class Codes: B65B 57/145 for fluent material
• CPC Class Codes: B65B 9/20 the webs being formed into tubes in situ around the filling nozzles

Abstract

A packaging machine (1) for continuously producing sealed packages (2) of a pourable food product from a tube (4) of heat-seal sheet packaging material fed along a vertical path (A) and filled continuously with the food product by means of a fill conduit (8) extending inside the tube (4). The packaging machine (1) has a capacitive level sensor (14) located outside the tube (4) and in turn having a plate element (20) made of conducting material, positioned facing the fill conduit (8), and defining, together with the fill conduit (8), a capacitive element (22) whose capacitance depends, among other things, on the amount of food product between its plates. The level sensor (14) also has a detecting circuit (24) connected to and for detecting the capacitance of the capacitive element (22), and generating a level signal (SL) indicating the level of the food product inside the tube (4).

Claims

1. A packaging machine for continuously producing sealed packages of pourable food product from a packaging tube of heat-sealable sheet packaging material, said packaging tube of heat-sealable sheet packaging material being fed along a vertical path within said packaging machine and said packaging tube of heat-sealable sheet packaging material being filled continuously with a food product thereby defining a level of food product inside said packaging tube of heat-sealable sheet packaging material, said packaging machine comprising:

a fill conduit disposed within said packaging machine, said fill conduit extending inside said packaging tube of heat-sealable sheet packaging material;

a capacitive level sensor means disposed within said packaging machine, said capacitive level sensor means being located outside said tube for detecting said level of food product inside said packaging tube of heat-sealable sheet packaging material;

a flow-regulating means for controlling flow of said food product through said fill conduit into said packaging tube of heat-sealable sheet packaging material

wherein said capacitive level sensor means comprises;

a plate element made of conducting material, said plate element being located outside said packaging tube of heat-sealable sheet packaging material, said plate element being separated from said fill conduit and facing said fill conduit;

a capacitive element defined by said plate element and said fill conduit, said capacitive element having a capacitance correlated to an amount of said food product inside said packaging tube of heat-sealable sheet packaging material between said plate element and said fill conduit;

a detecting means coupled with said capacitive element for detecting said capacitance, said detecting means having an output, said detecting means providing a level signal at said output indicating said level of food product inside said tube; and

a control circuit, said control circuit receiving said level signal from said output and generating a control signal, said control signal controlling said flow regulating means and said level of food product inside said packaging tube of heat-sealable sheet packaging material.

2. A packaging machine as recited in claim 1, wherein said plate element has a substantially trapezoidal shape for creating a linear relationship between speeds of increase of said level signal and said level of food product inside said packaging tube of heat-sealable sheet packaging material.

3. A packaging machine as set forth in claim 1, wherein the control signal controls said flow regulating means and said level of food product inside said packaging tube of heat-sealable sheet packaging material based on the level of food product inside the tube.

4. A packaging machine for continuously producing sealed packages of pourable food product from a packaging tube of heat-sealable sheet packaging material, said packaging tube of heat-sealable sheet packaging material being fed along a vertical path within said packaging machine and said packaging tube of heat-sealable sheet packaging material being filled continuously with a food product thereby defining a level of food product inside said packaging tube of heat-sealable sheet packaging material, said packaging machine comprising:

a fill conduit disposed within said packaging machine, said fill conduit extending inside said packaging tube of heat-sealable sheet packaging material;

a capacitive level sensor means disposed within said packaging machine, said capacitive level sensor means being located outside said tube for detecting said level of food product inside said packaging tube of heat-sealable sheet packaging material;

a flow-regulating means for controlling flow of said food product through said fill conduit into said packaging tube of heat-sealable sheet packaging material wherein said capacitive level sensor means comprises;

a plate element made of conducting material, said plate element being located outside said packaging tube of heat-sealable sheet packaging material, said plate element being separated from said fill conduit, said plate element facing said fill conduit and being shaped for creating a linear relationship between speeds of increase of said level signal and said level of food product inside said packaging tube of heat-sealable sheet packaging material;

a capacitive element defined by said plate element and said fill conduit, said capacitive element having a capacitance correlated to an amount of said food product inside said packaging tube of heat-sealable sheet packaging material between said plate element and said fill conduit;

a detecting means coupled with said capacitive element for detecting said capacitance, said detecting means having an output, said detecting means providing a level signal at said output indicating said level of food product inside said tube; and

a control circuit, said control circuit receiving said level signal from said output and generating a control signal, said control signal controlling said flow regulating means and said level of food product inside said packaging tube of heat-sealable sheet packaging material.

5. A combination according to claim 4, wherein said plate element has a substantially trapezoidal shape for creating said linear relationship between speeds of increase of said level signal and said level of said food product inside said packaging tube of heat-sealable sheet packaging material.

6. A packaging machine as set forth in claim 4, wherein the control signal controls said flow regulating means and said level of food product inside said packaging tube of heat-sealable sheet packaging material based on the level of food product inside the tube.