There are no products listed under this category.
Gear Pumps — Blackmer & Roper
Gear pumps are positive displacement workhorses for high‑viscosity, lubricating, or shear‑sensitive liquids. We engineer and supply internal gear (Blackmer G‑Series) and external gear (Roper) pumps with relief valves, steam/thermal jackets, mechanical seals or packing, and stainless or iron constructions. Typical duties include asphalt/bitumen, polymers, resins, adhesives, fuel & lube oils, chocolate/syrups, and chemical intermediates.
Not sure if you need internal vs. external gear, jacketed casings, hardened bushings, or API 676 alignment? Talk to a gear pump engineer—most quotes leave our inbox within one business hour.
Quick Selector: Blackmer vs. Roper Gear Pumps
| Manufacturer / Series (Representative) | Type | Typical Flow | Differential Pressure | Viscosity Range | Materials / Features | Best For |
|---|---|---|---|---|---|---|
| Blackmer G‑Series (Internal Gear) | Internal gear (bi‑directional, constant flow) | Up to ~500 GPM (model‑dependent) | Up to ~200+ PSI (model‑dependent) | ~1 to 1,000,000 cP | Cast iron, ductile iron, 316SS; relief valves; steam/thermal jackets | Asphalt, resins, polymers, chocolate, oils, chemicals |
| Roper (e.g., 3600/4600/ROC Series) | External & internal gear (broad coverage) | Up to ~1,000+ GPM (series‑dependent) | Up to ~300 PSI (series‑dependent) | ~1 to 1,000,000 cP | Cast iron, steel, 316SS; jacketed casings; packing or seals | Heavy oils, fuels, asphalt, paints/coatings, chemicals |
Values above are representative. We’ll confirm exact limits for your flow, pressure, temperature, viscosity, and metallurgy needs.
Why (and When) Gear Pumps Win
- Constant, pulse‑free flow proportional to speed
- Wide viscosity window (thin solvents to 1,000,000+ cP)
- Self‑priming, bi‑directional (internal gear especially)
- High differential pressures at relatively compact size
- Jacketed casings & heads for heating asphalt, resins, chocolate
- Built‑in or inline relief valves to protect from over‑pressure
How We Size Gear Pumps (So They Don’t Seize, Score, or Bypass Excessively)
1) Viscosity, Temperature & Clearances
We select the correct internal clearances, bushing/bearing materials, and speeds to match your viscosity (from 1 cP solvents to 1,000,000 cP polymers). For heat‑sensitive or solidifying fluids (asphalt, chocolate), we add steam/thermal jackets.
2) Pressure, Slip & Efficiency
Gear pumps handle high differential pressures—but we calculate internal slip at your viscosity and temperature to ensure the pump actually delivers the net flow you need at the pressure you require.
3) Sealing Strategy
Options include packing, single/double mechanical seals, barrier/flush plans, and in many cases **mag‑drive alternatives** (if eliminating fugitive emissions is critical—we’ll cross if needed).
4) Built‑In Relief Valves & System Protection
We specify internal relief valves (where available) or external bypass loops/valves to protect the pump from dead‑head or blocked discharge situations per best practice/API 676 guidance.
Brand / Series Snapshot
| Brand | Core Strengths | Options | Typical Uses |
|---|---|---|---|
| Blackmer G‑Series (Internal Gear) | Bi‑directional, constant flow on viscous fluids, integral relief valve availability | Iron/ductile iron/SS, jackets, packing or mechanical seals | Asphalt/bitumen, resins & polymers, food syrups/oils, lube & fuel oils, chemicals |
| Roper (External & Internal Gear) | Broad flow/pressure envelope, rugged designs for heavy oils and fuels | Cast iron/steel/SS, jacketed casings, packing or seals, API 676 alignment | Heavy fuels, asphalt, paints & coatings, chemical transfer, truck loading |
Common Gear Pump Applications
- Chemical & Petrochemical – polymers, resins, monomers, isocyanates
- Asphalt / Bitumen – jacketed heads, high viscosity, high temp
- Paints, Coatings & Adhesives – accurate, pulse‑free transfer
- Fuels & Lubricants – diesel, lube oil, heavy fuel oil (HFO)
- Food & Beverage – chocolate, syrups, molasses, oils (with sanitary options)
Parts, Kits & Accessories
- Relief valves & bypass loops (internal or external)
- Mechanical seal kits, packing sets, seal flush plans
- Hardened gears, bushings/bearings, wear plates
- Steam/thermal jackets, heat tracing, insulation kits
- Baseplates, alignment kits, VFDs, coupling guards
- Strainers, pressure gauges, temperature & vibration monitoring
Send your flow, ΔP, viscosity (cP), temp, metallurgy & sealing needs—quotes usually in < 1 hour.
Gear Pump FAQs
Internal vs. external gear—how do I choose?
Internal gear (e.g., Blackmer G‑Series) is bi‑directional, handles very high viscosities, and offers smooth, low‑pulsation flow. External gear (common in Roper’s portfolio) excels at higher pressures/precision metering and is often used on fuels, oils, and chemical transfer.
Do gear pumps need a relief valve?
Yes—every PD pump must be protected from over‑pressure. Many gear pumps offer an internal relief valve; otherwise, we’ll add an external bypass loop sized for your worst‑case flow.
Can gear pumps run dry?
Only briefly, if at all. Most rely on the pumped fluid for lubrication. We’ll verify your start‑up and upset conditions and, if dry‑run is likely, consider AODD or peristaltic alternatives or protective controls.
When do I need steam or thermal jackets?
If your product solidifies, gels, or becomes too viscous when cool (asphalt, chocolate, waxes, resins), jackets keep the pump hot so it can start, prime, and hit the duty point reliably.
Do you support API 676 / API 682 sealing requirements?
Yes—we can align with API 676 for rotary PD pumps and apply API 682 seal plans where specified. Tell us your spec package and we’ll configure accordingly.