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A.0500.751 – IM-TGBLOC/01.00 EN (10/2020)
3.10 Internals
3.10.1 Bush materials
Overview of bush materials and application field
Material Code
S
C
B
Material
Steel
Carbon
Bronze
Hydrodynamic
lubrication
if yes
to maximum working pressure = 16 bar
if no
6 bar (*)
10 bar (*)
6 bar (*)
Corrosive resistance
Fair
Good
Fair
Abrasive resistance
Slight
None
None
Dry running allowed
No
Yes
Moderate
Sensitive to thermal choc
No
No
No
Sensitive to blistering in oil
No
> 180°C
No
Oil aging
No
No
> 150°C
Food processing allowed
Yes
No (antimony)
No (lead)
(*) 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 BLOC pumps is limited to 180°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.
TG BLOC pump size
K.hyd
15-50
6250
23-65
4000
58-80
3750
86-100
3600
3.10.4 Maximum torque of pump shaft and rotor material combination
The maximum allowable torque
is a constant independent from speed and may not be exceeded to
avoid damaging the pump i.e. pump shaft, rotor/shaft fitting and rotor teeth.
TG BLOC pump size
Mn (nominal torque) in Nm
Md (starting torque) in Nm
G Rotor
Iron
R Rotor
Stainless
steel
G Rotor
Iron
R Rotor
Stainless
steel
15-50
255
255
360
360
23-65
255
255
360
360
58-80
390
390
550
550
86-100
600
600
840
840
The nominal torque (Mn) has to be checked for the normal working conditions and the installed
nominal motor torque (M n.motor) but converted to the pump shaft speed.
The starting torque (Md) may not be exceeded during start up. Use this value for the maximum torque
set of a torque limiter if installed on the pump shaft.
