VDMA, Hannover 2017files.messe.de/abstracts/79344_Trelleborg_14_30VDMA.pdfAll test results with...
Transcript of VDMA, Hannover 2017files.messe.de/abstracts/79344_Trelleborg_14_30VDMA.pdfAll test results with...
VDMA, Hannover 2017
Rotary slipper seals, physical limitations
2
Starved / non-existing
lubrication
High power-density
Potential seals rotation in
housing groove
Potential rotation between
seal parts
Temperature mainly limited
by hardware heat dissipation
No fluid exchange in contact
area
No removal of wear products
High mechanical loads on
rotary part
Practical considerations
3
Hardware
• Closed, symmetric
housing groove
• Standard groove
dimensions preferred
• Avoid back-to-back seals
installation between
channels
• Avoid internal drains
between channels
Seal
• Simple installation across
wide diameter range
• Suitable for high
temperature materials
• Suitable for fluid separation
• Symmetric, bi-directional
design preferred
• Uni-directional seal should
have poka-yoka features /
or positioning should be
verifiable
Prevention of seals rotation
4
Mechanical
Retention
Clamping
• Unidirectional
• Complicated
hardware
Lock seal
parts together
Bonding
• Poor installation
• Complicated
manufacturing
Reduce friction
Pressure balancing
• Not generally
bidirectional
• Assembly of
unidirectional seals
difficult to verify
Reduction of dynamic friction
5
By supporting fluid
film formation in the
contact area
And/or by introducing
pressure balancing
Bi-directional pressure-balancing
6
Existing concepts
+ O-ring automatically opens
high-pressure port
- Valve function highly sensitive
to tolerances
- Fundamentally less suited to
standard housing grooves
+ Pressure tilts seal body and
reduces pressurized contact
width
- Bi-directional function sensitive
to deformation in service
- Less suited for material with
low elasticity e.g. PTFE
Bi-directional pressure-balancing
7
Concept development
Standard rotary seal
design
Pressure ports close
against groove wall
Design idea
Bigger ports
Internal valve
element (O-Ring)
Refined contact
faces
Development
O-ring replaced by
Quadring
Further changes to
seal body
Final
Finalized design
8
Rotary seal performance, torque / time
9
All test results with mineral oil HLP46 and seal material Turcon M15
unless otherwise noted
0,00
1,00
2,00
3,00
4,00
5,00
0 50 100 150 200
Nm
Time (h)
50 mm shaft / 50 bar x 1 m/s
RTG
RTG-K
New Concept / RTG-V
0
1
2
3
4
5
6
7
8
0 50 100 150 200
Nm
Pressure (bar)
50 mm Shaft seal / 0,6 m/s
RTG
RTG-K
New Concept / RTG-V
Rotary seal performance, torque / pressure
10
0
10
20
30
40
0 50 100 150 200
Gram
Time (h)
50 mm Shaft seal / 50 bar x 1 m/s
RTG
New Concept / RTG-V
RTG-K
Rotary seal performance, Leakage / time
11
Rotary seal performance, Seal wear
12
50 mm shaft, 50 bar x 1 m/s, 200 hours
0
2
4
6
8
10
12
14
Sea
l ri
ng
wei
gh
t lo
ss [
wt%
]
RTG RTG-K New concept / RTG-V
0
2
4
6
8
10
12
14
O-R
ing
wei
gh
t lo
ss [
wt%
]
RTG RTG-K New concept/ RTG-V
Rotary seal performance, hardware wear
13
50 mm shaft, 50 bar x 1 m/s, 200 hours, pressure from left
Existing single-acting (RTG-K) New Concept / RTG-V
0
50
100
150
200
250
300
350
0 0,5 1 1,5 2 2,5 3 3,5
Bar
m / s
New Concept / RTG-V
RTG
Rotary seal performance, Limits
14
Limits for shafts ≥ Ø 50
Thank you for your attention