MDH-D & MDH(F)-D – Now REAL Dry Run Capability!
An industrial pump that looks, acts and runs like a heavy duty process pump, MDH boasts significant comparison to process pumps and striking contrast to conventional industrial pumps. Competitive price and outstanding performance make MDH an easy choice.
MDH and MDH-D pumps are constructed of Glass Fiber Reinforced Polypropylene or Carbon Fiber Reinforced Fluoroplastic (PVDF). MDH-D indicates that the pump has a carbon bushing and thus is not damaged by dry running.
These pumps use a plastic coated central support system that keeps the motor's mounting off of the floor to prevent corrosion to the motor if the pump sometimes sits in a puddle of liquid. Standard C face motors are used.
- Ceramic Spindle
- Carbon Bearing
- Molded Impeller
- Rear Casing
- Pin-Point Bearing
2) Bearing – Rifled Bearing forces fluid across the spindle surface to create a "liquid sleeve", resulting in reduced friction and rapid, even cooling of all bearing surfaces, prolonging pump life. Material is carbon (allows for dry running) or Alumina Ceramic.
3) Impellers – High efficiency enclosed impeller press fits to matching spindles surface on magnet capsule; no mechanical fastener is required. The enclosed design reduces hydraulic loading, improving bearing life. As with bigger process pumps, Iwaki Walchem routinely trims impellers to meet precise performance specifications across a wide specific gravity range. Machined and precision molded impeller components dramatically cut hydraulic noise.
- Mouth Ring – Made of PTFE, the replaceable mouth ring generates minimal heat and therefore less thermal deformation.
- Thrust Ring – Truncated ring design with positioning tabs assures perfect face mating.
- Modular replacement of impeller, magnet capsule, mouth ring and rifled flush bearing reduces maintenance expense.
4) Rear Casing – Large hydraulic efficiencies are maintained by the use of a non-metallic rear casing, eliminating eddy current heat found in metal magnetic drive pumps.
- NPT male threads prevent cracking of housing due to over tightening.
5) Patented pinpoint bearing system – With the new pinpoint bearing system, conventional rear thrust surfaces have been designed-out. During cavitation or dry run, rear thrust is balanced on the impeller-mounted pinpoint bearing. Frictional contact is thereby virtually eliminated. Heat generation, typical of other sealless pumps, is reduced exponentially.
Traditional magnetic drive pumps have always been subject to catastrophic failure as a result of dry run or cavitation. Liquid/air flow across bearing surfaces shuts down under adversity. Now, the new pinpoint bearing leaves the internal cooling circuit wide open. The magnet capsule is in all cases prevented from any contact with the rear casing. Note: Dry running feature only when using the carbon bushing.
- During manufacture, drive magnet carriers are dynamically balanced, referencing ISO standards 1940 & 2372.
- Cast iron motor bracket further increases inertial stability, reduces vibration, and dampens noise.
- Thermoplastic foot mount eliminates "wet floor" corrosion typical of metallic pump mounts.
- One Seal: Compared to other designs the MDH(F) has only one seal for the entire pump. This eliminates leak paths and makes maintenance even easier.
MDH -D polypro construction with carbon bushing
MDH (F)-D PVDF construction with carbon bushing
MDH polypro construction with ceramic bushing
MDH (F) PVDF construction with ceramic bushing
Dry run ability is only with carbon bushing - Ceramic bushing will fail in a short period of time if not pumping liquid and will cause additional damage to the pump.