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Liquid Ring Vacuum Pump 
Two Stage, AT

Capacity 400 to 2,800 ACFM (680 to 4,750 m3/h)

The popular NASH AT two stage vacuum pump series has been providing reliable high vacuum performance in the power industry for over 25 years. With capacity ranging from 400 to 2,800 ACFM (680 to 4,750 m³/hr), the AT's four vacuum pump models are an ideal choice when you need a rugged and long-lasting machine to handle your saturated process gases.


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Designed to Operate in Harsh Conditions

The line of AT vacuum pumps is our first generation of two stage pumps designed specifically for the condenser exhaust duty. Including an integral two stage rotor, the AT vacuum pump is designed to reach vacuum levels down to 0.8 in HgA (27 mbar abs). This is approximately 40% lower absolute pressure than a single stage pump.

AT liquid ring vacuum pumps were created for the chemical, petrochemical, and power industries.With their integral two stage rotors, AT pumps, are able to condense vapors that come off the process and to recover or dispose of them. 


Conical Porting and Rotor Configuration

Patented in 1932, Nash’s variable conical porting design allows the force of compression to counter the weight of the rotor and shaft to help minimize load on bearings during operation. The variable porting optimizes pump performance across the entire operating range. With constant innovation, Nash’s patented design features:

  • Option for lobe purge to minimize damage from erosion in duties with solids present

  • Large differential pressure capability

  • Gas scavenging feature minimizes slip of gas from discharge to inlet improving capacity, especially at deep vacuum

  • High liquid carryover tolerance

  • Side discharge to minimize chance of flooded start

  • Self-priming design may allow elimination of booster pump in recirculated systems


Reliable and Efficient with Proven Performance

The AT offers superior performance and reliability through the proven reliable NASH conical liquid ring pump design. The first AT3006 vacuum pump was built and tested at a Gardner Denver Nash facility with results showing an increased dry air capacity up to 25% in the high vacuum range without an increase in power usage. The AT3006 offers higher operating efficiency than the AT3004, and with today's energy costs, efficiency is an important factor for our customers. 

Whether you have an existing AT pump that is in need of service, repair or replacement with a new or remanufactured duplicate AT pump, Gardner Denver Nash is there to meet your needs.


Factory Service

Strategically located to provide support where and when you need it.



Built to our legendary standards using current designs and specifications. Fit and performance guaranteed.

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Field Service

Our team of NASH Certified Technicians are available to supplement your in-house maintenance operations.

Technical Data

  • Suction Capacity: 400 to 2,800 ACFM (680 to 4,750 m3/h)

  • Vacuum Range: to 0.8 inHgA (to 28 mbar abs.)

  • Shaft Seals: Stuffing box (standard)

  • Materials of Construction: Cast Iron

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