Internals; Bush Materials; Maximum Temperature Of Internals; Operation Under Hydrodynamic Lubrication Conditions - Johnson Pump TG GS2-25 Instruction Manual

Internal gear pumps
Table of Contents

Advertisement

3.10 Internals

3.10.1 Bush materials

Overview of bush materials and application field
Material Code
Material
Hydrodynamical
lubrication
Corrosive resistance
Abrasive resistance
Dry running allowed
Sensitive to thermal choc
Sensitive to blistering in oil
Oil aging
Food processing allowed
(*)
These are not absolute figures. Higher or lower values possible in function of the application,
expected lifetime etc.

3.10.2 Maximum temperature of internals

Because the overall temperature of TopGear GS pumps is limited to 200°C, there are no extra
temperature restrictions for internals.

3.10.3 Operation under hydrodynamic lubrication conditions

Hydrodynamic lubrication could be important criteria for bush material selection.
If the bush bearings are running under the condition of hydrodynamic lubrication there is no more
material contact between bush and pin or shaft and the lifetime cycle is increased importantly.
If there is no condition for hydrodynamic lubrication, the bush bearings make material contact with
pin or shaft and the wear of these parts is to be considered.
The condition of hydrodynamic lubrication is fulfilled
with the following equation:
Viscosity * shaft speed / diff.pressure ≥ K.hyd
with:
viscosity [mPa.s]
shaft speed [rpm]
diff.pressure [bar]
K.hyd = design constant for each pump size.
A.0500.501 – IM-TGGS/05.01 EN (03/2013)
S
C
Steel
Carbon
if yes
to maximum working pressure = 16 bar
if no
6 bar (*)
10 bar (*)
Fair
Good
Slight
None
No
Yes
No
No
No
> 180°C
No
No
Yes
No (antimony)
B
H
U
Bronze
Ceramic
Hard metal
6 bar (*)
6 bar (*)
10 bar (*)
Fair
Excellent
Good
None
Good
Good
Moderate
No
No
No
Yes dT<90°C
No
No
No
No
> 150°C
No
No
No (lead)
Yes
Yes
TG GS pump size
K.hyd
2-25
6000
3-32
7500
6-40
5500
15-50
6250
23-65
4000
58-80
3750
86-100
3600
185-125
2500
19

Hide quick links:

Advertisement

Table of Contents
loading

Table of Contents