Robbins & Myers 33259 Moyno 500 Motorized Progressing Cavity Pump Cast Iron
Model 33259 is a Moyno 500 Series progressing cavity pump in cast iron, running a chrome plated 416 stainless steel rotor in an NBR nitrile stator and supplied complete with a 1/2 HP single phase 115/230 VAC motor. It handles clean liquids, viscous liquids, abrasive liquids and liquids carrying solids using the same pumping principle throughout, with no valves to clog and no close clearances to block.
The 33259 is rated at 100 psig at 2.2 GPM with up to 4.5 GPM available, with 3/4 in FNPT suction and 3/4 in FNPT discharge connections and a maximum speed of 1750 RPM. Elastomer choice governs the liquids it can handle, with nitrile suited to roughly 10 to 160 F, EPDM to 10 to 210 F and fluoroelastomer to 10 to 240 F, and chemical compatibility mattering as much as temperature. Self priming to 25 feet of suction lift once wetted, it should never be started dry and should not be run below about ten percent of rated flow.
Key Features
- Genuine Robbins & Myers Moyno 500 Series progressing cavity pump
- Cast iron pump body
- Chrome plated 416 stainless steel rotor and NBR nitrile stator
- 1/2 HP single phase 115/230 VAC motor, close coupled
- Maximum discharge pressure of 100 psig at 2.2 GPM
- Maximum capacity of 4.5 GPM
- 3/4 in FNPT suction and 3/4 in FNPT discharge connections
- Self priming to 25 feet of suction lift once wetted
- Smooth, low shear, nonpulsating flow with no valves to clog
Applications
- Transfer and metering of clean, viscous and abrasive liquids
- Liquids carrying suspended solids that would block a close clearance pump
- Shear sensitive products that must not be churned or emulsified
- Dosing duties where output needs to follow shaft speed
- Suction lift installations drawing from sumps and below grade tanks
- Industrial, marine, dockside and process installations
- Direct replacement for a worn Moyno 500 33259 pump
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Model: 33259
- Series: Moyno 500 Series, 332 frame
- Pump Type: Progressing cavity, positive displacement
- Pump Body: Cast iron
- Rotor: Chrome plated 416 stainless steel
- Stator: NBR nitrile
- Motor: 1/2 HP single phase 115/230 VAC
- Maximum Capacity: 4.5 GPM
- Maximum Discharge Pressure: 100 psig at 2.2 GPM
- Connections: 3/4 in FNPT suction and 3/4 in FNPT discharge
- Maximum Speed: 1750 RPM
- Suction Lift: Up to 25 feet when wetted
- Maximum Viscosity: Approximately 20,000 cP with reduced speed
- Condition: New
Frequently Asked Questions
Q: Can the elastomer be changed later if the liquid changes?
Yes. Conversion kits supply the stator and the other soft parts in a different compound, which is far cheaper than replacing the pump when a duty changes.
Q: Can the pump be throttled to reduce flow?
No. A positive displacement pump keeps delivering whatever the shaft speed calls for, and closing a discharge valve simply raises pressure until something gives. Reduce output by slowing the drive, or return surplus flow to the tank through a relief line.
Q: Does it need a relief valve?
A relief or bypass on the discharge is strongly recommended on any positive displacement installation. Without one, a blocked or closed discharge has nowhere to go and the pressure rises until the pump, the drive or the pipework fails.
Q: Will it pass solids without blocking?
Within reason, yes. There are no valves and no close clearances of the kind that block a gear pump, so soft solids and suspended particles travel through the cavities. Abrasive solids will shorten stator life, which is a wear question rather than a blockage one.
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct pump before you order.
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