Type Designation; Function And Operating Principle - Johnson Pump MDR Series Instruction Manual

• The pump unit must not be exposed to rapid temperature changes of the liquid
without prior pre-heating/pre-cooling. Absolutely forbidden to flush a hot pump with
cold water. Big temperature changes can cause crack formation or explosion, which in
turn can entail severe personal injuries.
• The pump must not operate above stated performance.
• Before intervening in the pump/system, the power must be shut off and the starting
device be locked. When intervening in the pump unit, follow the instructions for
disassembly/assembly. If the instructions are not followed, the pump or parts of the
pump can be damaged. It will also invalidate the warranty.
• If the pump does not function satisfactorily, contact your distributor.

1.4 Type designation

MDR
Example
1 Family name
Magnetic Drive Centrifugal Pump
2 Pump size
45, 75, 85, 105, 116
3 Pump material
P2 = polyvinylidenfluoride (PVDF)
P3 = polypropylene (PP)
4 Impeller diameter
1V = full diameter for specific gravity up to 1.2 kg/dm
1VD = reduced diameter for specific gravity up to 1.8 kg/dm

1.5 Function and operating principle

The drive magnet, attached to the drive shaft transfers its torque to the impeller magnet.
The impeller can thereby rotate around the ceramic shaft in the pump body without any
physical contact between the drive shaft and the pump body. This makes the pump
completely leak-proof.
Ceramic shaft
Impeller magnet
MDR/EN (0909) 1.0
45 P2
1 2 3
Impeller
- 1V
4
and viscosity 10 cP
3
and viscosity 30 cP
3
Magnet housing
Drive magnet
Drive shaft
7