Does your rotary lobe pump stop you pumping solids or abrasives?
The 6 benefits of the Husky electric operated double diaphragm pump compared to rotary lobe pumps.
Rotary lobe pumps have limited compatibility with fluids and are extremely vulnerable because of their complex design, which can lead to hazardous situations and unusually high maintenance costs. Graco’s Husky electric operated double diaphragm (EODD) pumps address all of these issues.
Rotary lobe pumps
Rotary lobe pumps are used in a wide variety of industries and applications, because of their relatively small footprint and their ability to withstand high temperature. However, they suffer from certain disadvantages that can lead to frustrating downtime, expensive repairs and even product replacement.
- Reduced lift with thin liquids
Extra care is needed when selecting a rotary lobe pump for pumping thin non-lubricating liquids. All pumps have a small amount of liquid that goes from discharge back to suction. This is called slip and it varies with liquid viscosity and differential pressure. Some rotary lobe pumps can be used with thin liquids, and most manufacturers offer several options to handle the low lubricity and viscosity typically associated with thin liquids, but it adds more complexity to the pump selection procedure compared to using EODD pumps.
- High maintenance cost
Rotary lobe pumps are comprised of a number of rotating parts that need precision tolerances, which makes them more expensive to manufacture and maintain. In addition, expensive and sensitive seals can easily lead to leaks.
- Investment costs
Rotary lobe pumps are designed with rotors, which are synced by a separate gear in the back of the pump. This increases manufacturing cost. Add to this the two relatively expensive mechanical seals and, not surprisingly, investment costs are relatively high in comparison with other pump technologies on the market.
- Unsatisfactory solution for abrasives
The rotary lobe pump’s intricate and sensitive design is not ideal for abrasives, which are bound to damage the system and its expensive parts. The pump’s life cycle can be slightly extended by reducing pump speed and using hard parts in key wear areas, but EODD pumps are clearly a better fit when you need higher flow and long lasting durability.
- Unable to run dry for extended periods of time
A rotary lobe pump cannot run dry indefinitely without destroying its expensive stators and rotors. The pumped fluid acts as a lubricator between rotor and stator.
Graco Husky EODD pumps
The Husky EODD is an electric operated double diaphragm (EODD) pump from Graco. Compared to a traditional rotary lobe pump, the Husky EODD provides much more flexibility and a significantly lower maintenance cost. Take a look at the benefits:
- Self-priming
The Husky EODD is self-priming and has excellent suction capabilities.
- Seal-less
The Husky EODD seal-less diaphragm pump design eliminates leaking rotational seals and failures due to run-dry pump conditions.
- Low maintenance cost
The Husky EODD’s efficient and seal-less design ensures that it is not sensitive to wear and erosion and is easy to repair.
- Low pulsation
Through its unique low pulsation mode, the Husky EODD offers an exceptionally smooth flow with accurate metering capabilities.
- Stalls under pressure
Graco’s Husky EODD pump is the only electric diaphragm pump on the market that stalls under pressure, to prevent pump failures from clogged lines or closed valves.
- Runs dry
The Husky EODD pump can run dry indefinitely without causing any damage to the system, thus avoiding expensive repairs.
SUMMARY
These are the Husky electric double diaphragm (EODD) pump benefits in a nutshell
Rotary lobe pumps | Graco Husky EODD pumps |
Running dry will cause damage to the pump | Can run dry indefinitely |
High repair cost for spare parts | CEasy to repair at low cost |
High investment cost | More cost-effective, especially for larger flow rates |
Deadhead/stall causes severe damage | Easily deadheads/stalls with no additional equipment |
Abrasive-containing fluid can quickly cause failure | Easily handles all fluids with abrasives |
Shaft alignment difficult to maintain | No spinning shaft seals; no alignment necessary |
Very expensive for larger flow rates | Can handle large bulk flow rates |
Minimal suction capability | Self-priming pump with smooth flow |
Not ideal for thin non-lubricating liquids or low viscosity fluids | Suitable for all types of fluids |
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