How to choose gear pumps for chemical plants

In chemical plants, the selection of gear pumps requires comprehensive consideration of medium characteristics, process requirements, safety standards, and cost-effectiveness. The following are the key steps and precautions:

1. Clarify the characteristics of the medium

Chemical properties: corrosive (such as acid, alkali), toxic, flammable and explosive.   

Corrosive medium: Choose corrosion-resistant materials (such as stainless steel 316L, Hastelloy, PTFE lining).   

High viscosity medium: Choose a high-pressure gear pump with heating or insulation design to prevent solidification.   

Physical properties: viscosity, solid content, temperature.   

Medium containing particles: choose wear-resistant materials (such as silicon carbide seals) or add filtering devices.   

2. Determine process parameters

Flow and pressure: Select the pump displacement and head according to process requirements, leaving a margin of 10% to 20%.   

Temperature range: High temperature media require heat-resistant materials (such as high-temperature alloys) and cooling structures.   

Continuous/Intermittent Operation: Heavy duty pumps (such as cast steel shells) are selected for continuous operation, while intermittent operation can reduce costs.   

3. Material selection

Gear material:

Non corrosive: carbon steel, cast iron.   

Corrosivity: Stainless steel 304/316, duplex steel, ceramic coating.   

Sealing type:

Packing seal: Low cost, requiring regular maintenance.   

Mechanical seal: low leakage rate, high pressure resistance (optional double end face seal+flushing system).   

Magnetic drive: zero leakage, suitable for highly toxic/high-risk media.   

4. Consideration of special working conditions

Explosion proof requirements: Choose explosion-proof motors (Ex d/IIC T4 grade) for flammable and explosive environments.   

Hygiene requirements: Food/pharmaceutical grade products must comply with FDA or GMP standards (polished surface, easy to clean design).   

Wear resistant design: When conveying slurry, hardened gears or replaceable bushings are selected.   

5. Brand and Standards

Certification: Compliant with industry standards such as API 676 and ISO 2858.   

Supplier evaluation: after-sales support, spare parts supply, selection of gear pumps from Cangzhou Shiqi High Temperature Pump Industry Co., Ltd. in China.

6. Economic analysis

Total Cost of Ownership (TCO): including purchase price, energy consumption, maintenance costs, and downtime losses.   

Energy efficiency: Efficient motors or variable frequency control can reduce long-term operating costs.   

7. Common selection errors to avoid

Misconception 1: Only choose pumps based on price → ignore lifespan and maintenance costs.   

Misconception 2: Ignoring changes in the medium (such as viscosity fluctuations with temperature).   

Misconception 3: Improper sealing selection leads to leakage or frequent damage.   

By systematically evaluating the above factors, it can ensure the safe, efficient, and long-term operation of gear pumps in chemical environments. It is recommended to cooperate with professional suppliers or engineers to conduct working condition simulation or trial testing.