Product Metering Device

Patent metadata

Field	Value
Publication number	US-2018200748-A1
Application number	US-201615748319-A
Country	US
Kind code	A1
Filing date	Aug 17, 2016
Priority date	Aug 17, 2015
Publication date	Jul 19, 2018
Grant date	—

Abstract

A metering device is disclosed for regulating the depth of flowable product coating a surface movable relative to the metering device by directing an air curtain towards the surface. The metering device comprises a body ( 10 ) having an interior chamber ( 12 ), an inlet for connecting the chamber to a source of gas under super-ambient pressure; and an opening ( 16 ) communicating with the chamber and having a mouth through which gas is discharged from the chamber towards the surface to form the air curtain. A porous or reticulated membrane ( 18 ) is secured to, or formed integrally with, the body of the device to lie in the path of the gas discharged through the mouth of the opening.

First claim

1 . A product metering device for regulating the depth, or leveling, of a flowable product coating a surface that is movable relative to the metering device by directing an air curtain towards the surface, the metering device comprising a body having an interior chamber, an inlet for connecting the chamber to a source of gas under super-ambient pressure; and an opening communicating with the chamber and having a mouth through which gas is discharged from the chamber towards the surface to form the air curtain; wherein a porous or reticulated flow regulating membrane is secured to, or formed integrally with, the body of the device to lie in the path of the gas discharged through the mouth of the opening.

2 . A product metering device as claimed in claim 1 , wherein said membrane is designed and configured such that in an ambient mode (T=25° C., the gas is air, the distance between the metering device and the surface is substantially infinite), said membrane exerts a minimum back-pressure with respect to said chamber, such that a pressure differential ΔP−am defined by
2ΔP−am=Pchamber−am−Pambient;

wherein Pchamber−am is the pressure in the chamber and Pambient is the ambient pressure, is at least 0.2 bar, at least 0.4 bar, at least 0.7 bar, at least 1 bar, at least 1.5 bar, at least 2 bar, at least 3 bar, at least 5 bar, at least 10 bar, or at least 20 bar.

3 . A product metering device as claimed in claim 2 , wherein, with the metering device in said ambient mode and with said membrane detached from the product metering device, a membraneless pressure differential ΔPml is defined by:
ΔPml=Pchamber−ml−Pambient;

wherein Pchamber−ml is the back pressure in the chamber in the absence of a membrane, and a differential pressure ratio RΔP is defined by:
RΔP=ΔP−am/ΔPml

said differential pressure ratio is at least 7, at least 10, at least 15, at least 20, at least 30, at least 50, or at least 100.

4 . A product metering device as claimed in claim 1 , when positioned opposite a surface carrying a layer of the product, wherein the distance between the mouth of opening and the surface is less than 2 mm, or less than 1.5 mm, or less than 1 mm or less than 0.5 mm.

5 . A product metering device as claimed in claim 4 , wherein the air curtain flows substantially without turbulence in a gap between the metering device and the surface in order to achieve an even depth of product coating on the surface on the downstream side of the device, variations in coating depth being optionally less than 10%, or less than 5%, or less than 2% or less than 1% of the average depth of the coating.

6 . A product metering device as claimed in claim 1 , wherein the membrane is formed of a sheet made of at least one of a metal, ceramic, silica or plastic material, the sheet comprising fine holes having a diameter of 50 μm or less, 30 μm or less, or 20 μm or less.

7 . A product metering device as claimed in claim 1 , wherein the membrane is a mesh formed of at least one of metal, ceramic, silica or plastic fibers, a density of said fibers being such that an aperture between adjacent fibers is of 50 μm or less, 30 μm or less, or 20 μm or less.

8 . A product metering device as claimed in claim 1 , wherein the membrane is formed of a pressure resistant micro-porous membrane having micro pores of less than 50 μm, less than 30 μm, or less than 20 μm in diameter, the membrane being made of at least one of a metal, ceramic, silica or plastic material.

9 . A product metering device as claimed in claim 6 , wherein said fine holes diameter, aperture between adjacent fibers, and micro pores diameter, is of 10 μm or less, and of 10 nm or more, or 100 nm or more.

10 . A product metering device as claimed in claim 1 , wherein the membrane is formed of a hydrophobic material

11 . A product metering device as claimed in claim 1 , wherein the membrane is formed of a hydrophilic material.

12 . A product metering device as claimed in claim 1 , wherein the membrane is formed of a plastic material, selected from the group comprising at least one of ethylene vinyl acetate (EVA), high-density polyethylene (HDPE), polyamide (PA), polycarbonate (PC), polyethylene (PE), polyethersulfone (PES), polyester (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyurethane (PU or TPU), polyvinylidene fluoride (PVDF), and ultra-high molecular weight polyethylene (UHMWPE).

13 . A product metering device as claimed in claim 1 , wherein the membrane has a thickness in the range of 300-600 μm, or in the range of 300-450 μm.

14 . A product metering device as claimed in claim 1 , wherein the weight of the membrane is in the range of 100-1200 g/m 2 , 100-300 g/m 2 or 140-180 g/m 2 .

15 . A product metering device as claimed in claim 1 , wherein the density of the membrane is in the range of 0.3-8 g/cm 3 , 0.3-5 g/cm 3 , or 0.33-0.38 g/cm 3 .

16 . A product metering device as claimed claim 1 , wherein the flow resistance of the membrane is such that, when the pressure differential across the membrane is about 1,000 kPa, the gas flow rate is in the range of 0.01 to 5 liters/minute/mm 2 , 0.1 to 3 liters/minute/mm 2 or 1 to 2 liters/minute/mm 2 .

17 . A product metering device as claimed in claim 1 , wherein the membrane is preformed to conform to the shape of the outer surface of the body and is secured to the body mechanically or by means of an adhesive.

18 . A system for applying to a surface an even coating of a flowable product, in which system an excess of the product is placed on the surface and the surface is moved beneath a metering device that directs an air curtain towards the surface in order to spread the product evenly over the surface in order to achieve a desired coating depth, wherein the metering device comprises a body having an interior chamber, an inlet connecting the chamber to a source of gas under super-ambient pressure; and an opening communicating with the chamber and having a mouth through which gas is discharged from the chamber towards the surface to form the air curtain, and wherein a porous or reticulated flow regulating membrane is secured to, or formed integrally with, the body of the device to lie in the path of the gas discharged through the mouth of the opening.

19 . A system as claimed in claim 18 , wherein the distance between the mouth of opening and the surface is less than 2 mm, or less than 1.5 mm, or less than 1 mm or less than 0.5 mm.

20 . A system as claimed in claim 18 , wherein the air curtain flows substantially without turbulence in a gap between the metering device and the surface in order to achieve an even depth of product coating on the surface on the downstream side of the metering device, variations in coating depth being optionally less than 10%, or less than 5%, or less than 2% or less than 1% of the average depth of the coating.

Assignees

• Landa Labs 2012 Ltd

Inventors

• Landa Benzion
• Krassilnikov Anton

Classifications

• F26B21/50

  Ducting arrangements from the source of air or other gases to the materials or objects being dried · CPC title

• D21H25/16

  with a blast of vapour or gas, e.g. air knife · CPC title

• B05C11/023

  Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface (B05C11/021, B05C11/04 take precedence) · CPC title

• B05C11/06 Primary

  with a blast of gas or vapour · CPC title

• D21H5/007

  with a blast of gas or vapour, e.g. air knife · CPC title