GN 20 Levelling feet Hygienic Design, with and without mounting holes


Description

Specification

Types

  • Type A: without mounting holes
  • Type B: with mounting holes
Spindle, adjustable sleeve, foot plate
  • Stainless Steel AISI 304
  • turned
Seals, blue, FDA compliant
Sealing ring
NBR, hardness 70 ±5 Shore A
Wiper
TPU, hardness 95 ±5 Shore A
Joint sealing ring
H-NBR, hardness 85 ±5 Shore A
Bottom seal
Silicon, hardness 85 ±5 Shore A

Information

GN 20 hygienic levelling feet are certified according to 3-A Sanitary Standard, Inc. guidelines and are intended for use in hygiene areas. In addition, the version with mounting holes (type B) is certified according to EHEDG guidelines.
The bottom seal protects the area beneath the foot plate from dirt. For this, the foot must be screwed on using the mounting holes and compressed accordingly. Hygienic fastenings and the correct position of the mounting holes are essential. The sealing ring above the adjustment sleeve enables fastening without dead space. Due to the wiper or the ball seal, the moving components are sealed against the environment.
The high quality finish prevents adherence of dirt and facilitates cleaning.
The values listed in the table for static load capacity refer to a purely vertical load in relation to the leveling foot. Under normal operating conditions bending loads or angular loads are not uncommon and result in a reduction of load capacity, which must be taken into consideration.

Technical Information

General instructions

Why Hygienic Design?

In the food industry, medical technology and the pharmaceutical industry, product safety and consumer protection are becoming increasingly important. Due to their specific properties, standard parts in Hygienic Design can assist the production process in these sensitive areas and facilitate the manufacture of products with a long shelf life, which are free from preservatives.

Advantages of Hygienic Design

Less and shorter cleaning work (this can be up to 25 % of the production time), therefore
  • more time available for production
  • less fresh water consumption
  • lower energy consumption
  • less cleaning agent required
  • less production of waste water
  • lower total costs and saving of resources

Legal basis of Hygienic Design

EN 1672-2:2009 “Food machinery”
Machines must be able to be cleaned, i.e. they must be designed and constructed so that dirt can be removed with the recommended cleaning methods.
Machinery directive 2006/42/EC
Machines must be designed so that
  • materials can be easily and fully cleaned before each use and
  • no risk of infections or illness is created.
DIN EN ISO 14519:2008-07
Hygiene requirements for the design of machines
DIN EN 1672:2009-07
Food machinery – General design principles – Part 2

Requirements, design principles

Design requirements for Hygienic Design

Material
  • Non-rusting Stainless Steels
  • FDA and EU compliant plastics and elastomers
Surfaces
  • Surfaces must be able to be cleaned
  • Steps due to appliance configurations which are not aligned must be avoided
  • Seals must be designed so that no gaps occur
  • O-ring grooves must be hygienically designed
  • Contact with the product to be manufactured must be ruled out
  • Corners should preferably have a radius of 6 mm or more
Design / Geometry
The interior and exterior areas of all appliances, components or piping must be self-draining or be able to be drained and easy to clean.
Surface properties and roughness
Easy to clean with Ra < 0.8 μm

Design principles for Hygienic Design

EHEDG
  • European Hygienic Engineering & Design Group
  • non-profit European consortium of machine and food manufacturers as well their suppliers, research institutes, universities and government health agencies
  • approximately 45 guidelines
  • examination of products and issue of certificates
3-A Sanitary Standard, Inc.
  • non profit and independent association in the USA
  • three interest groups:
  • public and governmental health agencies, machine and food manufacturers
  • over 70 Sanitary Standards
  • examination of designs and processes, issue of certificates

Seals, application example

Seals

For the standard parts which are listed in Hygienic Design, seals have the central function of protecting dead spaces, gaps and cracks from the penetration of cleaning fluids or product residues.
For this, a defined pre-tension or pressing of the seals and wipers is necessary for a reliable and permanent seal in the installed condition. Within the Hygienic Design product family, seal installation spaces and seal cross sections are calculated and designed with simulation software, so that the necessary surface compression is achieved on installation and the seal material is not subjected to excess pressure.
A fundamental differentiation can be made between static and moving seals:
Is the static seal, application examples shown below the top faces the mounting surface (sealing ring) and the bottom faces the contact surface (bottom seal), so that the corresponding pressure is achieved by tightening. It should be ensured that all surfaces which make contact with the seal have a surface finish of al least Ra 0.8 µm.
The moving seals on the adjustable sleeve (wiper) and the ball joint (joint sealing ring) of the foot are designed so that they allow adjustment in both height and angle. With these too, the installation space together with the cross section of the seal ensures a gap-free, pre-tensioned seal.
Depending on the version and the type of use, it may be the case that seals may need to be replaced in case of damage or for preventative maintenance. For this, Elesa+Ganter supplies the relevant seals as spare parts or offers these under GN 7600 as standard parts for spare parts.

Mounting example

With the example of a GN 20 Hygienic Design levelling foot, the illustrated design shows how the various seal configurations can be designed.

GN 20-A
Filter
Description d1 d2 l1 d3 l2 l3 A/F 1 A/F 2 Static load
in kN
Weight
GN 20-80-M16-175-A 80 M 16 175 28 19 35 18 22 30 904
GN 20-80-M16-225-A 80 M 16 225 28 19 35 18 22 30 983
GN 20-80-M20-185-A 80 M 20 185 32 24 35 24 27 47 1115
GN 20-80-M20-235-A 80 M 20 235 32 24 35 24 27 47 1243
GN 20-80-M24-185-A 80 M 24 185 36 29 35 24 30 67 1284
GN 20-80-M24-235-A 80 M 24 235 36 29 35 24 30 67 1458
GN 20-100-M16-175-A 100 M 16 175 28 19 35 18 22 30 1171
GN 20-100-M16-225-A 100 M 16 225 28 19 35 18 22 30 1252
GN 20-100-M20-185-A 100 M 20 185 32 24 35 24 27 47 1385
GN 20-100-M20-235-A 100 M 20 235 32 24 35 24 27 47 1513
GN 20-100-M24-185-A 100 M 24 185 36 29 35 24 30 67 1546
GN 20-100-M24-235-A 100 M 24 235 36 29 35 24 30 67 1726
GN 20-120-M16-175-A 120 M 16 175 28 19 35 18 22 30 1465
GN 20-120-M16-225-A 120 M 16 225 28 19 35 18 22 30 1549
GN 20-120-M20-185-A 120 M 20 185 32 24 35 24 27 47 1691
GN 20-120-M20-235-A 120 M 20 235 32 24 35 24 27 47 1818
GN 20-120-M24-185-A 120 M 24 185 36 29 35 24 30 67 1853
GN 20-120-M24-235-A 120 M 24 235 36 29 35 24 30 67 2031
GN 20-B
Filter
Description d1 d2 l1 d3 d4 l2 l3 k A/F 1 A/F 2 Static load
in kN
Weight
GN 20-100-M16-175-B 100 M 16 175 28 12 19 35 69 18 22 30 1113
GN 20-100-M16-225-B 100 M 16 225 28 12 19 35 69 18 22 30 1193
GN 20-100-M20-185-B 100 M 20 185 32 12 24 35 69 24 27 47 1325
GN 20-100-M20-235-B 100 M 20 235 32 12 24 35 69 24 27 47 1455
GN 20-100-M24-185-B 100 M 24 185 36 12 29 35 69 24 30 67 1487
GN 20-100-M24-235-B 100 M 24 235 36 12 29 35 69 24 30 67 1668
GN 20-120-M16-175-B 120 M 16 175 28 12 19 35 89 18 22 30 1426
GN 20-120-M16-225-B 120 M 16 225 28 12 19 35 89 18 22 30 1508
GN 20-120-M20-185-B 120 M 20 185 32 12 24 35 89 24 27 47 1641
GN 20-120-M20-235-B 120 M 20 235 32 12 24 35 89 24 27 47 1765
GN 20-120-M24-185-B 120 M 24 185 36 12 29 35 89 24 30 67 1805
GN 20-120-M24-235-B 120 M 24 235 36 12 29 35 89 24 30 67 1980