There is often confusion about the terms “Extrusion Pump”, “Extrusion Gear Pump” and “Gear Metering Pump”. Here is an explanation:

Extrusion Pump

The extrusion pump is a type of air-operated (or hydraulic) piston pump used to transfer high viscosity materials from drums (55 gallon/200 liter) and pails. Such materials include fluids such as silicones, sealants, adhesives, primers, PVC sol, epoxies and greases.

Synonyms

• Drum Extrusion Pump
• Ram Pump or Ram Unit
• (Sealant Pump)

Typical Specifications

Air Inlet Pressure: 44-87 psi [3-6 bar]
Discharge Pressure: 3,626-5,076 psi [200-350 bar]
Pressure Ratio: up to 1:81 and higher

Manufacturers

• Graco
  High-pressure pumps, including the Senator and Viscount II range of transfer pumps, and the DynaMite 190 pump. The company calls some of its pumps “extruders”
• Binks
  MX series of high-pressure pumps
• Bando
  Drum extrusion pumps BD-960-581 and BD 960-401, dual-post pail pumps BD 990-581 and BD-990-401 and single-post pail pumps BD 980-581 and BD 980-401

Extrusion Gear Pump

Extrusion Gear Pumps, optimize the extrusion process of thermoplastics and polymers in an extruder. They generate a constant pressure (up to 200 bar and more) and ensure a constant flow of material, relieving the plastic or rubber extruder of pressure build-up. Typical applications include recycling, due to constant viscosity fluctuations, and film production, where the slightest flow fluctuations are immediately visible on the extruded products. The most appropriate term/synonyms would be “melt pump”.

Synonyms

• Extrusion Melt Pump
• Extruder Pump
• Extruder Gear Pump
• Hot Melt Gear Pump
• Melt Pump for Plastic Extrusion
• Gear Pump Extruder

Typical Specifications

IMPORTANT: Material must be previously melted (by plastic/rubber extruder)
Materials: PET, PS, PP, PE-LLD, PE-HD
Temperature (max.): 350°C [662°F]
Difference Pressure – standard (max.): 250 bar [3,626 psi]

Manufacturers

• Nordson type BKG
  melt and extrusion gear pumps, including model EP-SE / EP-SF (extrusion and compounding), MHDP (high pressure extrusion and compounding processes) and MP-SE / MP-SF (masterbatch and sensitive polymers).
• Maag type extrex
  melt gear pumps, including model RV/RB (manufacturing profiles) and extrex6, incl. EP, MP and SP (higher pressure applications), ER (extrusion and compounding)
• Dynisco type MSDP and MHDP
  melt pumps, including model MSDP (standard) and MHDP (high pressure)

Gear Metering Pump (Paint Applications)

Gear Metering Pumps are external gear pumps designed for precise, low-pulsation metering and dispensing of paint and similar fluids. Due to smaller gear sizes and extremely tight manufacturing tolerances, internal fluid slip is minimized and the pumps are capable of flow rates as low as 0.0005 lpm while operating at high pressures up to 700 bar [10,150 psi]. These gear metering pumps can achieve efficient performance even at low viscosities.

Synonyms

• Precision Gear Metering Pump
• Paint Gear Pump

Manufacturers

• Mahr
  MarCoat gear metering pump series
• Ransburg
  The RIF gear pump series, including RIF-0.5-02A, RIF-1.5-02P and RIF-3.0-02A
• Pomtava

FAQ: What is a hot melt pump?

The term “hot melt pump” is widely used in glue/adhesive dispensing applications and simply refers to the fact that this particular pump transfers hot melt. And it does not refer to a particular pump technology or system. Hot melt pumps are either piston pumps (instant output is available, work at higher pressure) or gear pumps (smooth flow at lower pressures).