Seal Information - Seal and Design

Seal Information

Use & Fitting of Seal

Our quality control methods for material and manufacturing processes ensure that all seals leaving our factories are in a condition capable of giving a long and reliable service life. We have found from many years experience, that premature seal failure can be avoided if the following recommendations are considered at the design and manufacturing stage of the cylinder:

  1. Specify piston and gland bearings which are adequately proportioned to support the cylinder loads. As a result of mounting misalignments and / or the working action of the cylinder, piston and gland bearings will be subjected to side-loading, causing damage to the rod or the tube surface and hence the seal, if the bearings are inadequate.
  2. Ensure that seals are stored distortion free in a cool, dry and dark place prior to fitting.
  3. Check that the seal housing is free from damage likely to harm the seal. Remove all sharp edges and burrs from metal parts, paying particular attention to ports, grooves and threads over or through which the seal passes during assembly.
  4. Clean all seal housing areas, ensuring that all metallic particles and other contaminants have been removed. Check that other surfaces adjacent to the passage of the seal on fitting are also free of dirt, swarf or other contaminants. Check that both static and dynamic housing surface finishes meet specifications.
  5. Where the difference between a thread diameter over which the seal must pass and the seal diameter is small, use some form of protection over the thread, such as a fitting sleeve made of hard plastic.
  6. Check that the seal is of the correct type, part number and size, and that the specified material is correct. If there is any doubt regarding the material contact your local Hallite sales office.
  7. Lubricate all seals and metal components liberally with clean operating fluid or a compatible grease prior to assembly. N.B. Silicone grease should not be used in normal hydraulic applications.
  8. Where seals fitted to sub-assemblies, such as pistons, are awaiting further fitting operations, ensure that the seals are not subjected to any misaligned or localised loading which will cause local deformation. Ensure that sub-assemblies remain clean.
  9. The use of metal levers is not recommended but should they be used it is imperative that they are completely smooth and free from nicks and burrs. When using them ensure that the metal surfaces adjacent to the seal are not damaged.
  10. Flush the hydraulic system thoroughly before connecting the cylinder to it.

Hydaulic Cylinder Layout

Typical hydraulic cylinder layout showing installation features to be considered for satisfactory seal life.

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Materials & Fluid Compatibility

Max. continuous working temperatures C° and temperature ranges for materials, within fluid power fluids

  SERVICE FLUIDS
Fluids based on mineral oils Greases Fuels
Material Continuous material service temp. range °C Inermittent material service temp. range °C Motor Oils Hypoid gear oils Automatic trans. fluid ISO 6743-4 Hydraulic oils (HL, HM, HV) Mineral oil based greases Silicon based greases Diesel fuel Fuel for gasoline, petrol engines - normal Fuel for gasoline, petrol engines - super
Temperature range
for fluid °C
    + 150
- 40
+ 150
- 40
+ 160
- 50
+ 100
- 30
+ 100
- 30
+ 250
- 50
     
     
Maximum continuous service temperature in fluids °C
NBR 70 IRHD
NBR 90 IRHD
Nitrile (medium)
+ 100
- 30
+ 100
- 30
100 90 100 100 100 100 * * *
FKM 75 IRHD
FKM 90 IRHD
Fluoro-elastomer
+ 200
- 20
+ 250
- 20
150 150 160 100 100 200 150 150 150
EPDM 70 IRHD
EPDM 80 IRHD
+ 120
- 50
+ 150
- 50
NS NS NS NS NS NS NS NS NS
VMQ 70 IRHD
Silicone
+ 200
- 55
+ 250
- 55
* * * * 100 * NS NS NS
HNBR 75 IRHD
Hydrogenated
nitrile
+ 200
- 55
+ 150
- 30
130 110 130 100 100 130 * * *
IIR
Butyl
+ 120
- 40
+ 140
- 40
NS NS NS NS NS 120 NS NS NS
FFKM
Perfluoroelastomer
+300 +200
+40 -20
  150 150 160 100 100 200 150 150 150
AU
Polyester PU
+ 100
- 30
+ 110
- 30
100 100 100 100 100 100 60 60 60
EU
Polyether PU
+ 100
- 40
+ 110
- 45
100 100 100 100 100 100 60 60 60
Polyester
elastomer
+ 100
- 40
+ 120
- 40
100 100 100 100 100 100 60 60 60
PA
Polyamide
+ 100
- 40
+ 120
- 40
100 100 100 100 100 100 100 100 100
POM
Acetal
+ 100
- 45
+ 120
- 45
100 100 100 100 100 100 100 100 100
PPS
Polyphenylene
sulphide
+ 200
- 40
+ 200
- 40
150 150 160 100 100 200 150 150 150
PTFE
Polytetrafluoroethylene
+ 200
- 200
+ 200
- 200
150 150 160 100 100 200 150 150 150
Thermosetting
polyester resin
+ 100
- 50
+ 130
- 200
100 100 100 100 100 100 100 100 100
PEEK
Polyetheretherketone
+ 250
- 65
+ 300
- 65
150 150 160 100 100 250 150 150 150

* Denotes that values vary greatly for individual elastomers within this group NS Denotes that the elastomer is not suitable
The work of the BFPA technical working group ‘TC16/WG8’in the compilation of this table is acknowledged.

 

Service Fluids
Fire-resistant hydraulic fluids Enviornmentally acceptable fluids Other service fluids
ISO 6743-4 HFA fluids (5/95 water based) ISO 6743-4 HFB fluids (60/40 invert emulsion) ISO 6743-4 HFDR fluids (water glycol) ISO 6743-4 HFDR fluids (phosphate ester ALKYL (aero)) ISO 6743-4 HFDR fluids (phosphate ester ARYL (ind.)) ISO 6743-4 HETG fluids (Vegetable oil based) ISO 6743-4 HEES fluids (Synthetic ester based) ISO 6743-4 HEPG fluids (Synthetic glycol based) ISO 6743-4 HEPR fluids (Synthetic hydrocarbons) Water Air Brake Fluid
+ 60
+ 5
+ 60
+ 5
+ 60
-30
+ 100
- 50
+ 150
- 0
+ 60
- 10
+ 100
- 40
+ 100
- 50
+ 150
- 50
+ 60 (1)
+ 5
+ 200
+ 2
+ 130
- 50
Maximum continuous service temperature in fluids °C
60 60 60 NS NS 60 60 60 100 80 100 NS
60 60 NS NS 150 60 100 80 150 100 200 NS
NS NS 60 80 80 NS NS NS NS 120 120 120
NS NS NS NS NS NS NS NS * 100 200 80
60 60 80 NS NS 60 60 80 130 130 130 NS
NS NS 60 100 120 NS NS NS NS 120 120 80
60 60 60 100 150 60 100 100 150 150 200 130
40 40 NS NS NS 60 60 80 100 40 40 NS
60 60 40 NS NS 60 80 60 100 60 80 NS
60 60 NS NS NS 60 80 60 100 60 80 NS
60 60 60 100 100 60 100 100 100 60 80 80
60 60 60 100 100 60 100 100 100 80 80 80
60 60 60 100 150 60 100 100 150 150 200 130
60 60 60 100 150 60 100 100 150 150 200 130
60 60 40 100 100 60 100 100 100 80 100 NS
60 60 60 100 150 60 100 100 150 150 200 NS

In view of the variations in formulation of both oils and polymers, the compatibility of all combinations should be confirmed by testing and field service performance for each application.
(1) Temperature range for water in fluid power applications.

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Materials

Material Name Material Group Designation Temperature Hardness Colour Rod Piston Wiper Bearing  
°C °F
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 93 IRHD Black H        
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 90 IRHD Black     H    
Nitrile - high Synthetic rubber NBR -10 +140 -14 +284 80 IRHD Black P P P    
Nitrile - low Synthetic rubber NBR -45 +100 - -45 +212 80 IRHD Black   H      
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 78 78 IRHD Black   H     M(1)
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 78 75 IRHD Black Black H H      
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 78 73 IRHD Black Black H H      
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 78 70 IRHD Black H H      
Nitrile - low Synthetic rubber NBR -45 +100 -45 +212 70 IRHD Black H H      
Nitrile - medium 407 Synthetic rubber NBR -30 +120 -22 +250 78 70 IRHD Black   H      
Nitrile - low 407 LT Synthetic rubber NBR -56 +100 -70 +212 70 IRHD Black   H      
Nitrile - medium Synthetic rubber NBR -30 +120 -22 +250 78 65 IRHD Black   H      
Hallprene -rubber/fabric Composite Cotton/NBR -30 +120 -22 +250   Black H H      
Fluoroelastomer - rubber/fabric Composite Cotton/FKM -20 +150 -4 +302   Black H H      
Fluoroelastomer Synthetic rubber FKM -20 +200 -4 +392 75 IRHD Black HP HP HP    
Hythane 181 TPE EU -45 +110 -50 +230 93 IRHD Blue HP HP HP    
Hythane 282 TPE   -30 +125 -22 +255 93 IRHD Purple HP HP HP   M
Polyurethane TPE AU -40 +100 -40 +212 94 IRHD Dark Blue H H H    
Polyurethane TPE AU -30 +100 -22 +212 93 IRHD Dark Blue     H    
Standard polyester elastomer TPE   -40 +120 -40 +250 55 D Red   H H    
Hydrolysis stabilised polyester elastomer TPE   -40 +120 -40 +250 55 D Grey H H     M
Hydrolysis stabilised polyester elastomer TPE   -40 +140 -40 +284 72 D Red   H     M
Lubricated stabilised polyester elastomer TPE   -40 +120 -40 +250 55 D Dark Brown   HP      
Acetal Eng. plastic POM -45 +120 -50 +250 R 115 Orange H H   HP M
PTFE glass filled Eng. plastic PFTE -50 +200 -58 +392 60 D White HP HP      
PTFE Glass / MoS2 filled Eng. plastic PFTE -50 +200 -58 +392 62 D Grey H H   H  
PTFE Bronze filled Eng. plastic PFTE -50 +200 -58 +392 72 D Bronze HP HP   HP  
Hallite 506 polyester / polyester Eng. plastic   -40 +120 -40 +250   Red       HP M
Nylon 12 Composite PA -40 +120 -40 +250 72 D Brown   H      
Nylon 6 / MoS2 Eng. plastic PA -40 +120 -40 +250 R 115 Black H H      
Glass filled Nylon Eng. plastic PA -40 +120 -40 +250 R 124 Black H H   H  

H - Hydraulic P - Pneumatic
M - Suitable for water based fluids
(1) Static applications only

 

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Housing & Installation Data

Compressiver bearing stres vs strain for non metallic materialsHallite 87 & 506 bearing strip

Hallite 87 strip is a low friction PTFE & Bronze compound produced in a flat tape style ready for easy cutting to size to suit individual applications and is particularly effective in friction conscious applications such as servo cylinders.

Hallite 506 can be supplied in spiral lengths, generally in 10 metre, as individual cut bearings and also in 10 metre lengths packed flat in a box dispenser. Hallite506 bearing strip is manufactured to extremely accurate thickness tolerances, ensuring reliable cylinder alignment. Other sizes of type 506 are available on request, special sections and diameters can also be produced to suit individual requirements.

Bearing Type Standard material
87 PTFE + Bronze
506 Polyester + PTFE

Bearing strip housing tolerances

As tolerances are not specified “on line” for types 87 &
506, please refer to the information below for tolerances

Hallite 506 specified tolerances   Hallite 506 specified tolerances
  Bearing length L1 Bearing cross section S     Bearing length L1 Bearing cross section S
Tolerances (mm) -0.1 to -0.6 -0.02 to -0.1   Tolerances (in.) -0.005 to -0.015 -0.001 to -0.004
 
Type 506 & 87 specified tolerances   Type 506 & 87 specified tolerances

Nominal dimension range (mm)

Tolerances
(units 0.001 mm)
  Nominal dimension range (in.) Tolerances (units 0.001 in.)
over to f9 H9 H10 H11   over to f9 H9 H10 H11
10 18 -16 -59 +43
0
+70
0
+110
0
  .40 .71 -.06
-2.3
+1.6
0
+2.8
0
+4.0
0
18 30 -20
-72
+52
0
+84
0
+130
0
  .71 1.19 -0.8
-2.8
+2.0
0
+3.5
0
+5.0
0
30 50 -25
-87
+62
0
+100
0
+160
0
  1.19 1.97 -1.0
-3.4
+2.5
0
+4.0
0
+6.0
0
50 80 -30
-104
+74
0
+120
0
+190
0
  1.97 3.15 -1.2
-4.1
+3.0
0
+4.5
0
+7.0
0
80 120 -36
-123
+87
0
+140
0
+220
0
  3.15 4.73 -1.4
-4.8
+3.5
0
+5.0
0
+9.0
0
120 180 -43
-143
+100
0
+160
0
+250
0
  4.73 7.09 -1.6
-5.6
+4.0
0
+6.0
0
+10.0
0
180 250 -50
-165
+115
0
+185
0
+290
0
  7.09 9.85 -2.0
-6.5
+4.5
0
+7.0
0
+12.0
0
250 315 -56
-186
+130
0
+210
0
+320   9.85 12.41 -2.2
-7.3
+5.0
0
+8.0
0
+12.0
0
315 400 -62
-212
+140
0
+230
0
+360
0
  12.41 15.75 -2.5
-8.3
+6.0
0
+9.0
0
+14.0
0
400 500 -68
-223
+155
0
+250
0
+400
0
  15.75 19.69 -2.8
-8.8
+6.0
0
+10.0
0
+16.0
0
500 630 -76
-251
+175
0
+280
0
+440
0
  19.69 24.80 -3.0
-9.9
+6.9
0
-11.0
0
+17.3
0
630 800 -80
-280
+200
0
+320
0
+500
0
  24.80 31.49 -3.1
-11.0
+7.9
0
+12.6
0
+19.7
0
800 1000 -86
-316
+230
0
+360
0
+560
0
  31.49 39.37 -3.4
-12.4
+9.1
0
-14.2
0
+22.0
0

Specified tolerance

Nominal sizes mm Shafts (outside diameter) Units 0.001 mm Bores (outside diameter)
Units 0.001 mm
over to f8 f9 h8 h9 h10 h11 js10 js11 H8 H9 H10 H11 Js11
1.6 3 -6 -20 -6 -31 0 -14 0 -25 0 -40 0 -60 +20 -20 +30 -30 +14 0 +25 0 +40 0 +60 0 +30 -30
3 6 -10 -28 -10 -40 0 -18 0 -30 0 -48 0 -75 +24 -24 +37.5 -37.5 +18 0 +30 0 +48 0 +75 0 +37.5 -37.5
6 10 -13 -35 -13 -49 0 -22 0 -36 0 -58 0 -90 +29 -29 +45 -45 +22 0 +36 0 +58 0 +90 0 +45 -45
10 18 -16 -43 -16 -59 0 -27 0 -43 0 -70 0 -110 +35 -35 +55 -55 +27 0 +43 0 +70 0 +110 0 +55 -55
18 30 -20 -53 -20 -72 0 -33 0 -52 0 -84 0 -130 +42 -42 +65 -65 +33 0 +52 0 +84 0 +130 0 +65 -65
30 50 -25 -64 -25 -87 0 -39 0 -62 0 -100 0 -160 +50 -50 +80 -80 +39 0 +62 0 +100 0 +160 0 +80 -80
50 80 -30 -76 -30 -104 0 -46 0 -74 0 -120 0 -190 +60 -60 +95 -95 +46 0 +74 0 +120 0 +190 0 +95 -95
80 120 -36 -90 -36 -123 0 -54 0 -87 0 -140 0 -220 +70 -70 +110 -110 +54 0 +87 0 +140 0 +220 0 +110 -110
120 180 -43 -106 -43 -143 0 -63 0 -100 0 -160 0 -250 +80 -80 +125 -125 +63 0 +100 0 +160 0 +250 0 +125 -125
180 250 -50 -122 -50 -165 0 -72 0 -115 0 -185 0 -290 +92 -92 +145 -145 +72 0 +115 0 +185 0 +290 0 +145 -145
250 315 -56 -137 -56 -186 0 -81 0 -130 0 -210 0 -320 +105 -105 +160 -160 +81 0 +130 0 +210 0 +320 0 +160 -160
315 400 -62 -151 -62 -202 0 -89 0 -140 0 -230 0 -360 +115 -115 +180 -180 +89 0 +140 0 +230 0 +360 0 +180 -180
400 500 -68 -165 -68 -223 0 -97 0 -155 0 -250 0 -400 +125 -125 +200 -200 +97 0 +155 0 +250 0 +400 0 +200 -200
500 630 -76 -186 -76 -251 0 -110 0 -175 0 -280 0 -440 +140 -140 +220 -220 +110 0 +175 0 +280 0 +440 0 +220 -220
630 800 -80 -205 -80 -280 0 -125 0 -200 0 -320 0 -500 +160 -160   +125 0 +200 0 +320 0 +500 0  

 


Nominal sizes in.
Shafts (outside diameter)
Units 0.001 in.
Bores (outside diameter) Units 0.001 in.
 
over to f8 f9 h8 h9 h10 h11 js10 js11 H8 H9 H10 H11 Js11
0.04 0.12 -0.3 -0.9 -0.3 -1.2 0 -0.6 0 -1.0 0 -1.6 0 -2.5 +0.8 -0.8 +1.3 -1.3 +0.6 0 +1.0 0 +1.6 0 +2.5 0 +1.3 -1.3
0.12 0.24 -0.4 -1.1 -0.4 -1.6 0 -0.7 0 -1.2 0 -1.8 0 -3.0 +0.9 -0.9 +1.5 -1.5 +0.7 0 +1.2 0 +1.8 0 +3.0 0 +1.5 -1.5
0.24 0.40 -0.5 -1.4 -0.5 -1.9 0 -0.9 0 -1.4 0 -2.2 0 -3.5 +1.1 -1.1 +1.8 -1.8 +0.9 0 +1.4 0 +2.2 0 +3.5 0 +1.8 -1.8
0.40 0.71 -0.6 -1.6 -0.6 -2.3 0 -1.0 0 -1.6 0 -2.8 0 -4.0 +1.4 -1.4 +2.0 -2.0 +1.0 0 +1.6 0 +2.8 0 +4.0 0 +2.0 -2.0
0.71 1.19 -0.8 -2.0 -0.8 -2.8 0 -1.2 0 -2.0 0 -3.5 0 -5.0 +1.8 -1.8 +2.5 -2.5 +1.2 0 +2.0 0 +3.5 0 +5.0 0 +2.5 -2.5
1.19 1.97 -1.0 -2.6 -1.0 -3.4 0 -1.6 0 -2.5 0 -4.0 0 -6.0 +2.0 -2.0 +3.0 -3.0 +1.6 0 +2.5 0 +4.0 0 +6.0 0 +3.0 -3.0
1.97 3.15 -1.2 -3.0 -1.2 -4.1 0 -1.8 0 -3.0 0 -4.5 0 -7.0 +2.3 -2.3 +3.5 -3.5 +1.8 0 +3.0 0 +4.5 0 +7.0 0 +3.5 -3.5
3.15 4.73 -1.4 -3.6 -1.4 -4.8 0 -2.2 0 -3.5 0 -5.0 0 -9.0 +2.5 -2.5 +4.5 -4.5 +2.2 0 +3.5 0 +5.0 0 +9.0 0 +4.5 -4.5
4.73 7.09 -1.6 -4.1 -1.6 -5.6 0 -2.5 0 -4.0 0 -6.0 0 -10.0 +3.0 -3.0 +5.0 -5.0 +2.5 0 +4.0 0 +6.0 0 +10.0 0 +5.0 -5.0
7.09 9.85 -2.0 -4.8 -2.0 -6.5 0 -2.8 0 -4.5 0 -7.0 0 -12.0 +3.5 -3.5 +6.0 -6.0 +2.8 0 +4.5 0 +7.0 0 +12.0 0 +6.0 -6.0
9.85 12.41 -2.2 -5.2 -2.2 -7.3 0 -3.0 0 -5 0 -8.0 0 -12.0 +4.0 -4.0 +6.0 -6.0 +3.0 0 +5.0 0 +8.0 0 +12.0 0 +6.0 -6.0
12.41 15.75 -2.5 -6.0 -2.5 -8.0 0 -3.5 0 -6.0 0 -9.0 0 -14.0 +4.5 -4.5 +7.0 -7.0 +3.5 0 +6.0 0 +9.0 0 +14.0 0 +7.0 -7.0
15.75 19.69 -2.8 -6.5 -2.8 -8.8 0 -4.0 0 -6.0 0 -10.0 0 -16.0 +5.0 -5.0 +8.0 -8.0 +4.0 0 +6.0 0 +10.0 0 +16.0 0 +8.0 -8.0
19.69 24.80 -3.0 -7.0 -3.0 -9.9 0 -4.3 0 -6.9 0 -11.0 0 -17.3 +5.5 -5.5 +8.7 -8.7 +4.3 0 +6.9 0 +11.0 0 +17.3 0 +8.7 -8.7
24.80 31.49 -3.1 -8.1 -3.1 -11.0 0 -4.9 0 -7.9 0 -12.6 0 -19.7 +6.3 -6.3 +9.8 -9.8 +4.9 0 +7.9 0 +12.6 0 +19.7 0 +9.8 -9.8

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Housing Design

Hallite Seals’ product data sheets give information indicating the allowable extrusion gap a seal can see at pressure during its working life. The extrusion gap can be calculated using the tolerance build ups within the cylinder and any dilation that may occur under pressure. Maximum extrusion gap = F max (see drawing below). F max is the maximum extrusion gap for the seal Minimum metal to metal clearance = F min (see drawing below). F min for cylinders with minimal side loading should be > 0.1mm (0.004”).

Rods

Maximum extrusion gap

Rob Bearing & Piston Bearing

Note: Rod is not concentric with gland, because of clearances.
(shown exaggerated)
Note: Piston is not concentric with cylinder bore, because of clearances.
(shown exaggerated)

Pistons

Pistons
Calculate both F max and F min.
Ensure the F min is greater than 0.1mm (0.004”) and F max is less than the maximum extrusion gap stated on the seal data sheet at the application’s working pressure.

For built-in metal bearings, the extrusion gap calculation is simpler.

For F max:
Rod = ØD3 max - Ød1 min + dilation
Piston = ØD1max - Ød3 min + dilation

F min must be zero

Extrusion is closely linked to pressure and temperature. In general, the best seal performance and life is provided by specifying the smallest possible extrusion gap. The figures shown for the extrusion gap within the operating conditions of Hallite’s product data sheets, relate to the maximum permissible, worst case situation with the gap all on one side.

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Housing Design & Seal Options

Cylinder housings and seal options

The following diagrams illustrate how Hallite’s wide range of products can be applied to a selection
of some of the most popular cylinder designs servicing the world’s fluid power industry.

The diagrams show different gland and piston arrangements to illustrate alternative sealing methods
currently in use and a suitable Hallite product.

If the application which you are interested in is of a non-standard nature please contact Hallite’s
technical department.

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Operating Conditions

Cylinder
Specification
Light Duty Medium Duty Heavy Duty
Pressure
     Max.
     Normal
     Working

350 bar 5000 psi
160 bar 2300 psi
No Pressure Peaks

500 bar 7500 psi
250 bar 3600 psi
Intermittent Pressure Peaks

700 bar 10000 psi
400 bar 6000 pis
Regular Pressure Peaks
Design Lower operating stresses. Rigid well aligned mounting, minimal side loading. Steady operating stresses with intermittent high stress, some side loading. Highly stressed for majority of its working life. Side loading common.
Condition of Fluid Good system filtration no cylinder contamination likely. Good system filtration but some cylinder contamination likely. Contamination unavoidable from internal and external sources.
Working Environment Clean, and inside a building. Operating temperature variations limited. Mixture of indorr & outdoors but some protection from the weather. Outdoors all the time or a dirty indoor area. Wide variations in temperature, both ambient & working. Difficult services conditions
Usage Irregular with short section of stroke at working pressures. Regular usage but at low pressure. Regular usage with most of the stroke at working pressure. Large amount of usage at high pressure with peaks throughout the stroke.
Typical Applications

Machine tools, lifting equipment, mechanical handling, injection moulding machines, control and robot equipment, agricultural machinery, packaging equipment, aircraft equipment & light duty tippers.

Heavy duty lifting equipment, agricultural equipment, light duty off road vehicles, cranes & lifting platforms, heavy duty machine tool & injection moulding machines, some auxiliary mining machinery, aircraft equipment, presses, heavy duty tippers (telescopic), heavy duty mechanical handling. Foundry & metal fabrication plant, mining machinery, roof supports, heavy duty earth moving machinery, heavy duty off-road vehicles, heavy duty presses.

Pressure, Speed, Temperature Range

From many years of application experience with sealing hydraulic equipment, supported by the results from an extensive test programme, we know that it is necessary to link the three main operating features of speed, pressure, and temperature to achieve a satisfactory seal performance. After carefully considering each product we are able to specify the maximum speed and pressure with a temperature range within which the seal will operate safely.

If your operating conditions do not comply with those recommended please send your details to your local Hallite sales office.

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Storage of Seals

Storage conditions

Most polymeric items including vulcanized rubber and other elastomers tend to change their properties during storage and may become unserviceable. This may be due to hardening, softening, cracking, crazing or other degradation and may be the result of oxygen, ozone, light, heat and/or humidity.

The following recommendations indicate the most suitable conditions for storing elastomeric items, whether as a single item or composite product.

  1. Temperature
    Storage temperatures should not exceed 75 F. Low temperatures are not permanently harmful provided the rubber items are handled carefully and not distorted. When taken from low temperatures items should be raised to approximatley 85 F before they are used.
  2. Humidity
    Optimum humidity is about 65% in a draft-free atmosphere.
  3. Light
    Protection from direct sunlight and strong artificial light with a high ultraviolet content is important. Unless packed in opaque containers, it is advisable to cover windows with red or orange screens or coatings.
  4. Oxygen and Ozone
    Elastomeric items should be protected from circulating air wherever possible. As ozone is particularly harmful to rubber, storage rooms should be free from equipment that may give rise to electric sparks or discharge. Wrapping, storage in airtight containers or other suitable means should be used for vulcanised rubber items.
  5. Deformation
    Where possible, rubber items should be stored in a relaxed position, free from tension or compression. Laying the item flat and avoiding suspension or crushing keeps it free from strain and minimises deformation.
  6. Contact with Liquid and Semi-Solid Material
    Contact with liquids and semi-solid materials, particularly solvents, such as oils or greases should be avoided unless so packed by the manufacturer.
  7. Contact with Metals
    Metals such as manganese, iron and copper, or copper alloys can have a harmful effect on rubber. A layer of paper, polyethylene or cellophane will keep these separated.
  8. Contact with Non-Metals
    Contact with other rubbers or creosotes should be avoided.
  9. Stock Rotation
    Elastomers should be stored for as short a period as possible, and strict stock rotation should be practiced.
  10. Cleaning
    Organic solvents such as trichloroethylene, carbon tetrachloride and petroleum are the most harmful agents. Soap and water and methylated spirits are the least harmful, and all parts should be dried at room temperature before use.
  11. Shelf Life
    The table shows the storage life of seal components made from the more common materials under ideal conditions. Storing under less than ideal conditions will reduce the life.

Careful inspection of the following should be made before installation after storage:

a. Mechanical damage
b. Permanent distortion
c. Cracks or surface crazing
d. Tackiness or surface softening/hardening

The appearance of 'bloom' is relatively unimportant, except in certain non-toxic applications. Thin components (less than 1/16in/1.6mm) tend to be more critically affected.

BASE POLYMER
(ISO DESIGNATION)
PRIMARY STORAGE PERIOD (YEARS) EXTENSION OF STORAGE PERIOD AFTER RE-INSPECTION (YEARS)
FLUOROCARBON (FKM)
ETHYLENE PROPYLENE (EPDM)
10 5
NITRILE (NBR)
HYTHANE (EU)
THERMOPLASTIC POLYESTER ELASTOMER
7 3
POLYUERETHANE (AU) 5 2
ENGINEERING THERMO PLASTICS:
ACETAL (POM)
POLYAMIDE (PA)
GLASSFILLED NYLON (PA)
PTFE
POLYPHENYLENE SULFIDE (PPS)
UNLIMITED  
ENGINEERING THERMOSETS:
TYPE 506 BEARING STRIP
UNLIMITED