Cast Iron Air-Operated Double Diaphragm Pump, Threaded ends

Cast‑iron air‑operated double diaphragm pump (QBY3 series) adopts cast‑iron pump housing with threaded connection ports, powered by compressed air. It is widely used for slurry, wastewater and general‑corrosive liquid transfer.

Flexible diaphragms fully separate conveyed medium from internal drive components for zero‑leak transfer. Multiple diaphragm materials (NBR, Neoprene, EPDM, PTFE, FEP) can be selected for different chemical compatibility.

Features
• Robust cast‑iron pump body with threaded NPT / BSP connection ends
• Self‑priming performance, no priming water needed before startup
• Good solid‑particle passing capacity for slurry and particle‑containing media
• Short‑time dry‑running is permitted (continuous long‑time dry‑running is prohibited)
• Flow and head can be stepless adjusted by regulating air‑supply pressure
• No rotating shaft seal, low leakage risk
• All‑bolted construction with serviceable external air‑valve assembly
• Compact layout, few wearing parts, simple installation and maintenance

⚠️ Important Safety Notes
1. Max air supply pressure shall NOT exceed 0.7 MPa.
2. When handling flammable & volatile liquids: reliable pump and piping grounding is mandatory for static elimination.
3. Allowable medium temperature is determined by diaphragm material, not the pump body. Confirm temperature limit of selected wetted components.

Applications
Suitable for mining, wastewater treatment, petroleum, metallurgy, coating, printing and paper‑making industries. Handles waste water, slurry, paint, glue and general corrosive media.

The connection schematic diagram for Double Diaphragm Pumps

Double Diaphragm Pump Dimendions :