How to choose a pneumatic conveying elbow

A bend changes the direction of the gas and solids together. It must fit the pipe, survive the duty and preserve the required product quality. Start with the process, then choose the construction.

1. Define the job

Identify the material, required throughput and current problem. Is the priority wear, particle damage, streamers, contamination, blockage, space or cleaning? Record the current elbow’s life and operating conditions.

2. Establish the operating envelope

Record minimum, normal and maximum solids throughput, pressure or vacuum, gas flow and temperature. State whether gas flow is measured at actual or reference conditions.

3. Confirm actual dimensions

Measure pipe outside diameter, wall thickness and clear bore. Record bend angle, centerline radius, end connections, bolt pattern and available space. Nominal pipe size, tube outside diameter and DN are not interchangeable.

4. Compare geometry

A swept bend offers a continuous curve. Compact deflection or pocket designs change the particle trajectory differently. Evaluate pressure demand, particle damage and retention as well as wear.

5. Compare construction

Internal ceramic linings, external reinforced backs and hardened metals have different implications for impact, compatibility, repair and inspection.

6. Check the whole assembly

Confirm housing, liner, joining materials, seals, connections, support loads and temperature limits. A flange designation alone does not establish the pressure rating of the complete elbow.

7. Review cleaning and contamination

Define acceptable residue, product-contact documentation and inspection access. Check every pocket, cavity, joint or liner edge where material could remain.

8. Specify an acceptance test

Compare candidates at the same throughput and material conditions. Measure wear, conveyed tonnes to replacement, product damage, pressure demand, deposits and cleaning time.

9. Compare lifecycle cost

Include purchase, installation, lost production, replacement frequency, energy, cleaning and product losses.