Tuthill 4C2B-C-7 Cast Iron Gear Pump End 36 GPM 1-1/2 in NPT
The Tuthill 4C2B-C-7 is a cast iron C Series rotary gear pump end rated at a nominal 36 GPM through 1-1/2 inch NPT inlet and outlet ports. It is supplied as a bare wet end with no motor, ready to be coupled, adapter mounted or built into an original equipment package. Pumping action comes from a rotor and an idler gear either side of a crescent cast integral with the cover. Two moving parts means very little to wear, and the series is rated across a wide viscosity band from 40 to 10,000 SSU.
This build is flange mount with a Viton mechanical seal, which sets its pressure envelope: inlet pressure to 250 PSI, maximum differential pressure of 150 PSI and maximum discharge pressure of 300 PSI. There is no internal relief valve on this build, so a positive displacement pump like this one needs an external bypass somewhere in the discharge piping before it is put to work. The C2B build carries a mechanical seal instead of a lip seal, which lifts the allowable inlet pressure to 250 PSI and the maximum discharge pressure to 300 PSI. Its seal is the 3C1B9-7 Viton mechanical seal and the matching bolt on foot is the 3C81. Like all C Series pumps it must not be used on plain water, corrosive liquids or abrasive slurries, and it must never be run dry.
Key Features
- Cast iron internal gear construction with only two moving parts
- Nominal capacity of 36 GPM through 1-1/2 inch NPT inlet and outlet ports
- Flange mount with a Viton mechanical seal
- Wide viscosity range of 40 to 10,000 SSU covers thin oils through heavy stock
- Straightforward wet end with no internal valve to set or maintain
- Rotors in forged steel with sintered steel idler gears and precision bronze bearings
- Built for clockwise rotation viewed from the shaft end
Applications
- Lubrication circuits on air compressors, gas compressors and gearboxes
- Burner oil and fuel oil transfer and circulation
- Low pressure hydraulic supply and control circuits
- Heat transfer oil, quench oil and process oil circulation
- Original equipment packages built around a bare gear pump end
- Transfer duty on viscous non abrasive industrial fluids
Specifications
- Brand: Tuthill
- Manufacturer Part Number: 4C2B-C-7
- Part Type: Rotary gear pump end, no motor supplied
- Series: C Series, size 4
- Nominal Capacity: 36 GPM
- Ports: 1-1/2 inch NPT inlet and outlet
- Mounting: Flange mount
- Shaft Seal: Viton mechanical seal
- Rotation: Clockwise
- Housing and Cover: Cast iron ASTM A48
- Rotor: Forged steel
- Idler Gear: Sintered steel
- Bearings: Precision bronze
- Maximum Inlet Pressure: 250 PSI
- Maximum Differential Pressure: 150 PSI
- Maximum Discharge Pressure: 300 PSI
- Relief Valve: None fitted
- Viscosity Range: 40 to 10,000 SSU
- Condition: New
Frequently Asked Questions
Q: Where does the relief valve adjusting screw have to point?
On the suction side of the pump. Fitting it the other way round leaves the valve unable to relieve properly, and it is one of the easiest things to get wrong on reassembly.
Q: Can it run at the full 10,000 SSU viscosity?
Yes, but not at full speed. Heavy stock needs the pump slowed down, and the required suction head roughly doubles at the top of the viscosity range compared with a thin oil.
Q: Does the pump self prime?
It will prime on its own once the internals are wetted, but the ports should face upward on installation so air can clear. If nothing is discharged after about sixty seconds, stop and find out why rather than letting it run.
Q: Is a motor or a mounting foot included?
No. This is a bare pump end. Mounting feet are listed separately by pump size, and C face adapters are published across the NEMA range from 56C up to 326TC.
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 end.
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