MTH Pumps - Model M50 and L50 Series -Vertical Base Mount and Horizontal Pedestal Mounted Multi-Stage Regenerative Turbine Pumps

• 2 - 40 GPM up to 2300 Feet of Head
• Close Coupled, Vertical Base Mounted, or Flexible Coupled Pumps
• L50 offers Low NPSH Inducer Style
• All Bronze, Bronze Fitted, All Iron, or Cast 316 Stainless Steel Construction Available
• Product Details & Specifications

• Capacities to 40 GPM
• Heads to 2300 Feet
• Single or Multi-stage Units (up to 5)
• Horizontal Close Coupled
• Horizontal Flexible Coupled
• Vertical Close Coupled

Water Passage Design

MTH masters one of the most critical design considerations of regenerative turbine pumps - the shaping of water passageways to achieve maximum capacity and pressure while minimizing horsepower requirements. By optimizing water passageway cross-sectional profiles for each impeller, MTH improves both efficiency and pressure in the M50 Series, and exceeds the standards realized by previous techniques.

Impeller Profile

One of the most notable improvements in regenerative turbine pump technology, incorporated in M50 Series pumps, involves the ability to determine the optimum impeller width and blade length. These factors have a significant effect on the required horsepower versus pressure curve for regenerative turbine pumps. By optimizing these for each pump, peak efficiency is improved and "off peak" horsepower requirements are reduced as well.

Impeller Blades

After the most favorable impeller profile has been determined for a particular water passageway cross-section, MTH calculates the number of blades needed to maximize the performance of that pump. The blade design in M50 Series pumps increases both efficiency and design pressure without incurring the manufacturing difficulties associated with producing contoured blade impellers. State-of-the-art computer controlled machines simplify manufacturing of the various MTH impellers utilized in the M50 Series. The result is a high performance pump providing efficiency characteristics exceeding those of much more expensive units.

NPSH Requirements

M50 • L50 Series regenerative turbine pumps meet low net positive suction head (NPSH) requirements without efficiency loss. This is achieved by keeping the inlet fluid velocity low and then gently accelerating to passageway velocities. Special ramps are responsible for this gentle fluid entry into the impeller blades and account for the high inlet efficiency of the M50 • L50 Series pumps.

Low NPSH Requirements

L50 Series regenerative turbine pumps have exceptionally low NPSH requirements, making them ideally suited for applications where very little inlet head is available.

This reduced NPSHR provided by the L50 Series is obtained by using a first stage centrifugal style impeller with inlet flow paths shaped to maintain a constant fluid velocity. This reduces entry losses to the impeller as well as maintaining efficiency. A multi-vane diffuser is used in conjunction with the centrifugal impeller for balancing radial loads and extracting the maximum pressure from the first stage. Pressure and flow produced by the NPSH inducer assures that the succeeding stages are adequately fed.

Steep Head/Capacity Curve

Pumping capacity varies only slightly as pressure changes. Steep pressure characteristic overcomes temporary line resistances.

Self-Adjusting Impeller

M50 • L50 impellers utilize balancing holes to promote hydraulic self centering, which eliminates the need for external adjustment. The free sliding impeller exerts no thrust load on the bearings, thereby extending service life. Self-centering is equally effective whether mounted in the horizontal or vertical position.

Mechanical Seals

Bronze fitted pumps have Buna N elastomers, carbon washer, ceramic seat, and stainless steel metal parts. Optional seats and materials are available.

1000 PSI Case Working Pressure

Rigid stucture is designed for maximum casing strength.

100% Tested

Every pump is fully tested to verify performance prior to shipment.

Volatile Fluid Handling

The turbine impeller handles vapors up to 20% by volume, minimizing the possibility of vapor lock.

"O"Ring Gaskets

"O"ring gaskets are used throughout the M50 • L50 Series pumps to assure positive sealing.

Shaft

Standard shaft is of high strength 416 stainless steel.

Motors

Standard 56C face motors are utilized up to 3 Hp. Five Hp and above are TEFC on vertical base mount units.

Best Efficiency

New pump designs optimize efficiency for each size.

Non-Cavitating

M50 • L50 Series pumps may be operated under adverse inlet conditions without audible or measurable cavitation.

Low NPSH

New inlet designs along with L50 Series inducer style pumps provide superior fluid handling ability with low inlet head conditions.

Balanced Loads

By staggering each stage`s discharge by 180°, the radial loads on the bearings are effectively balanced, and shaft deflection is thereby negligible.

Interstage Bushings

Close tolerance self-lubricating carbon bearings between each stage limit interstage leakage.

Construction Materials

Bronze fitted, all iron, all bronze and cast 316 stainless steel are available as stock materials.

Bearing Pedestals

All models can be pedestal mounted for flexible coupled drive.

"O"Ring Gaskets

Buna, EPR, Viton, Neoprene, and Teflon are available.

Mechanical Seals

Buna, EPR, Viton, Neoprene, and Teflon elastomers, tungsten, silicon carbide or ni-resist seats.

Flush Line

An external flush line from pump discharge to seal face (when used with the optional silicon carbide seat), allows operation in water up to 250°F.

Water Seal Connection

A tapped opening can be provided for seal flushing from an external source.

Inlet Strainer

A 90° suction strainer with a replaceable stainless steel screen is available for installation in the suction line to aid in preventing foreign material from entering the pump. A cap at the bottom of the strainer can be easily and quickly removed for screen cleaning or replacement.