Robbins & Myers 33301 Moyno 500 Progressing Cavity Pump 9 GPM Cast Iron
Model 33301 is a Moyno 500 Series progressing cavity pump in cast iron, running a chrome plated 416 stainless steel rotor in an NBR nitrile stator. 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 33301 is rated at 50 psig at 4.4 GPM with up to 9 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
- Bare shaft pump for coupling to your own drive
- Maximum discharge pressure of 50 psig at 4.4 GPM
- Maximum capacity of 9 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 33301 pump
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Model: 33301
- Series: Moyno 500 Series, 333 frame
- Pump Type: Progressing cavity, positive displacement
- Pump Body: Cast iron
- Rotor: Chrome plated 416 stainless steel
- Stator: NBR nitrile
- Drive: Bare shaft, no motor supplied
- Maximum Capacity: 9 GPM
- Maximum Discharge Pressure: 50 psig at 4.4 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: What happens if it runs backwards?
The pump will try to push liquid towards the suction line and can pressurise pipework never intended for it. Confirm rotation after any rewiring or motor change, before the pump is asked to move liquid.
Q: How is the flow rate adjusted for a dosing duty?
Through shaft speed. Output is close to proportional to speed across the range, which is what makes these pumps straightforward to meter with a variable speed drive.
Q: What is the single most common cause of failure?
Running dry. The liquid is what lubricates and cools the rotor and stator, and without it the stator is destroyed in minutes. A low level cut out on the supply tank is the cheapest insurance an installation can have.
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.
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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