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In 1930s Paul Bungartz, founder of Paul Bungartz GmbH & Co. KG, started working to solve problems related to mechanical seal and severe pumping applications which can be  typically found in the chemical and fertilizer industry


Invention of Hydrodynamic shaft sealing system was a revolutionary solution for tough applications where conventional centrifugal pumps did not last long.


Followingly , in 1947 Bungartz started the pump manufacturing business with the idea of producing trouble free pumps and lowest possible maintenance requirements for tough applications which was based on invention of hydrodynamic shaft seal to eliminate the problems that normal centrifugal pumps face.

Major Advantages

of V-AN Type


No Cavitation

No  Pit Requirement

No Additional Safety  Equip.

V-AN : Bungartz Self Adjusting Vertical Pump

Basically , hydro-dynamic shaft seal is based on regular impeller having back-vanes as seen in photos. When the pump is in operation, the back vanes creats a higher pressure than the impeller vanes itself. This higher pressure of the back vanes create a liquid free area around the shaft and seal the pump, only by a simple physically effect, during pump operation.

Hamitbat Power Plant Steam
Turbine Condensate Pump

Following video , can be watched a few times, was created to demonstrate this hydrodynamic shaft sealing property and dry shaft area.



Another unique solution of Bungartz is called V-AN pump. This is a vertical Bungartz pump utilizing hydrodynamic shaft seal plus additional special configurations to manage below issues :

•Hydrodynamic shaft seal

•Self-regulating pump type V-AN

          Vertical type, solids not settling at shaft seal

          NPSHR 0m, no cavitation

         Can handle gas and solids up to 50%

         Self - regulating

         Self – venting during operation

         No instrumentation required to protect pump against dry run (pump runs dry by design)

         Discontinuous and continuous flows


•Robust shaft seal


•Bearing lifetime: 25,000hrs and above

•NO PIT REQUIREMENT , Pump can operate at normal operation level

Image on the right indicates , the basic installation of V-AN pump and yellow color is for the fluid when pump is in operation and blue is during standstill of pump.


Details of V-AN Design

If Gas Balance Line is closed, pump operates like a regular self-priming pump. If gas balance line is open, the special pump design creates a direct connection to the gas phase of the intake tank. Due to this, the pump is not able to suck anymore.

The consequence: A pump which is not able able to suck anymore can also not cravitate anymore, too !

*In boiling condition


*With gasses

V-AN pumps have three

nozzles instead of two standard


- 1 suction nozzle 

- 1 discharge nozzle

- 1 gas balance nozzle

The animation shows the typically installation of the V-AN pump and the relationship between intake head in the vessel/tank and the pump flow. The Gas balance line must be connected to the gas phase of the intake tank/vessel, to get all the advantages of the V-AN Design.

Basically the pump operates like a chiffon and as long as the intake head increases, pumped flowrate increases, and vice-versa.


Below video demonstrates 2 conditions of V-AN pump

-When the gas balance line is closed, pump is not different than self-priming pumps

-But when it is open, pump utilizes hydro-dynamic seal, gas galance line and impeller geometry so achieve dry-running, self-adjusting pump :

Above video can be watched a few times to understand how the pump operates. If you have any questions, pls. don’t hesitate to contact us for specific questions :

Email :

Additional videos for working under VACUUM (boiling fluid) & GAS are also below :

Most frequent application of V-AN Pumps in power plants is CONDENSATE application. Due to the advantages of V-AN pump, complete investment of condensate pump application is less than regular centrifugal pumps.


Below is an illustration of a regular pump and V-AN pump. Here you can see easily that investor can save costs of

-pit construction

-condensate tank

-limit switches

-frequency convertor

-seal water not required

-mechanical seal cost eliminated

                      COMPARISON OF
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