Products > Submersible pumps > TSURUMI Japan > Contractor pumps > Unique features

A - Tsurumi Stuffing Box - absolutely watertight !
The stuffing box is located at the cable entry section and takes the part of sealing off water.

As the cable counductors consist of twisted wires, water may penetrate into the motor by the capillary phenomenon when cable sheath or insulation is damaged o r when the end of the cable is submerged. The construction is such that a certain part of the insulation of each conductor is peeled and filled with rubber or epoxy resin for the complete sealing.

B - Continuous use under dry-run

Located directly above the motor windings, a snap-action self-resetting bi-metal device cuts off voltage from all three phase windings simultaneously if the current is too large in one, two or all three windings, or if the windings get too hot.
It is important for a mobile pump to retain protection when its control box is crushed or gets wet inside, and when the cable is damaged. By achieving this without the use of a solenoid switch, Tsurumi enables measurement of winding resistance and insulation from the far end of the cable, without ever removing the cover from the motor in the field.

C - Double mechanical SiC seal in oil bath with Oil Lifter

The interaction of a ring rotating with the shaft and a fixed ring, below and above an oil bath, assumes the critical role of withstanding pumping pressure and preventing water from seeping into the motor. The seals of all Tsurumi contractors´ pumps, even in the 400W-class, have sealing rings of Silicon Carbide. No other material has greater hardness, selflubrication is slightly better than that of directly comparable materials. Resistance to temperature fluctuation and corrosion is also the best available.
The KTZ and LH-series are equipped with specially developed mechanical seals withstanding water pressure up to 10bar/100mH 20.

• A Motor side
• B Sealing face
• C Impeller side
• D Upper stationary part
• E Upper rotary part
• F Oil chamber
• G Spring 
• H Lower rotary part
• I Lower stationary part

D - The patented Oil Lifter

- a special guide vane -  is attached inside the oil chamber. With the motor rotation oil is pumped up. Therfore even at low oil level lubrication and cooling of the mechanical seal is secured.

E - Pump casing and Impeller

As contractors´ pumps are used in unpredictable circumstances, Tsurumi has gone a long way towards making the impeller capable of the impossible and towards providing spare motor power to match.

Tsurumi contractors´ pumps are used extensively for bentonite, mud and water containing sand.


F - Ball bearings of highest quality

Due to the high quality of the shaft and the bearrings all pumps can be run horizontally when entirely submerged.