Standard Pumps acc. to DIN EN 733


The Standard OH1 pumps acc. to DIN EN 733 are single stage, single flow volute casing pumps of horizontal design, with end suction flange and centerlined vertical discharge flange. The complete bearing bracket, including intermediate casing with shaft sealing and impeller, forms a back-pull-out unit.

Outline dimensions and performance range comply with the requirements of DIN EN 733. The performance range is subdivided such that the available pump sizes grant best efficiency at all service conditions.

Field of Application

These pumps are applicable as circulation pumps in comunicipal areas, the industry and the agriculture. They are suitable for handling cooling water, condensate, hot water, washing lyes, solvents, hydrobarbons and similar non-volatile products.

Volute casing, Flange design

The one-piece volute casing is provided with integrally cast feet for mounting on the base plate. Suction- and discharge flanges are in accordance with DIN 2532 / PN 10 respectively DIN 2533 / PN 16.


These pumps have closed impellers, constructed as single piece castings, hydraulically balanced by throttle gap and relief bores to keep occuring axial loads to a minimum. All impellers are dynamically balanced acc. to DIN ISO 1940 / part 1 with a minimum balance grade of G 6.3 that grants a smooth run of the pump free of vibrations. The impellers are keyed to the pump shaft in overhung position and are secured by shaft nuts.

Wear Rings

The pumps are of standard design have no wear rings provided. But the construction of intermediate and volute casing allows remachining and a subsequent installation of wear rings in case of worn out casings or impellers.

Pump shaft

The pump shafts are capable for receiving the driving power transmission. The shaft stiffness allows only minor deflection over the operating range of the pump and ensures high reliability of the unit. The pumps are manufactured of corrosion resistant material. Pumps with balanced mechanical seals are provided with shaft sleeves.


The pump shaft is carried in generously dimensioned grease lubricated antifriction bearings, located outside the pumped liquid. Nipples for regreasing are provided. Oil lubrication with constant level oiler is available as an option. The average service life of the bearings reaches 16000 operating hours.

Standard materials:

Volute casing: GGG40.3
Intermediate casing: GGG40.3 / St37
Impeller: dia < 250mm - GG25
  dia > 250mm - GGG40.3
Shaft: 1.4021
Bearing bracket: GG25

Mechanical seals

Considering the different applications, these pumps can be fitted with single acting mechanical seals as follows:

Unbalanced standard mechanical seal, design "R". Maximum allowable pressure p = 7 bar. Maximum temperature 180°C (hot water max. 140°C). Faces Carbon/SiC. Balanced standard mechanical seal, design "Re". Maximum allowable pressure p = 16 bar. Maximum temperature 200°C (hot water 140°C). Faces Carbon/SiC.

Metal bellows mechanical seal, design "N6". Maximum allowable pressure p = 7 bar. Maximum temperature 150°C. Faces Carbon/SiC. Balanced standard mechanical seal, design "Ge" for hot water service with external circulation from discharge to mechanical seal, through air cooled cooling loop and throat gap. Faces Carbon/SiC. Maximum allowable pressure p = 25 bar. Maximum temperature 180°C.