4924A Series Liquid-Specific Refrigeration Ammonia Internal Gear Pumps
Viking’s 4924A Series™ Positive Displacement (PD) pumps offer safety, reliability and high efficiency in refrigeration ammonia recirculation applications. Safety is achieved through use of a double mechanical dynamic shaft seal located between bearings for minimum possible shaft run-out, with a pressurized barrier fluid system, and O-ring type static seals where components are joined.
Reliability is provided by slow speed operation and low differential pressures, which maximize bearing and seal life. And efficiency is inherent in the PD Internal Gear pumping principle, compared to centrifugal pumps. Viking pumps can usually use at least one motor size smaller than these technologies.
AMMONIA (REFRIGERANT R-717) - Ammonia (Refrigerant R-717) is a very thin liquid that is a gas at ambient temperature and pressure. It is typically kept at elevated pressure to keep it in liquid form. Ammonia is used as the refrigerant in cooling systems.
In vapor compression ammonia refrigeration systems, liquid ammonia in the evaporator coils absorbs heat, and some flashes to a gas before recompression. Viking pumps “overfeed” the evaporator to ensure that the ammonia in the evaporator coils is liquid, which is more efficient at removing heat than a gas. Viking 4924A Series™ draw liquid ammonia from an accumulator vessel and pump it to the evaporator and back in a closed loop. Liquid and gaseous ammonia are separated in the accumulator and the gas is recompressed and flows to the condenser where it rejects heat, then to a receiver and back to the accumulator in a closed loop. The Viking pumps’ slow speeds enable very low NPSHr to prevent flashing and cavitation. Their high efficiency, with air-cooled motor, add almost no heat to the system, increasing overall cooling efficiency.
Viking Pump 4924A Series Features & Benefits
• Pressurized oil reservoir ensures barrier between inboard and outboard seals.
• Sight glass enables easy verification of oil level.
• Rotatable bearing housing simplified end clearance adjustment.
• Return-to-tank pressure relief valve prevents overpressure (HL valve shown. Others extend with poppet parallel to shaft).
• Rigid, one-piece cast iron bracket with seal between bearings helps prevent misalignment to ensure long seal life.
• Double mechanical seal with oil barrier for maximum safety.
• Lubricated idler bushing with pressure lubrication system (K, KK, LQ, LL sizes) provides constant film of liquid between idler pin and bushing for long life, regardless of pump rotation.
• Static o-ring seals between casing, head and bracket provide superior joint sealing.
Specifications
Capacity: 10 to 60 GPM, 2.3 to 13.6 m³/h
Pressure: to 50 PSI, to 3.5 Bar
Temperature: -40 to +225 °F, -40 to +105 °C
Porting: Flanged (ASME / ANSI), NPT
Drives: R Offset Gear Reducer Drive | P Purchased Gear Reducer Drive | V Drive | V-Belt Drive
Mounting: Foot Mount
Sealing: Mechanical Seals
Typical Applications: Ammonia | Evaporator Liquid Overfeed I System Filling and Emptying
