Even the most perfectly matched sections of pipework won’t create an airtight seal by themselves. Any tiny gaps will allow air to leak from your pneumatic conveying system, leading to pressure drops and excessive power consumption. Contaminants such as dust could also enter the pipes, affecting the quality of your products and the performance of your equipment.

To protect against these issues, manufacturers install compression couplings in every place where two sections of pipework meet. As well as creating an airtight seal of constant, uniform pressure, compression couplings hold your system together during operation.

But for compression couplings to function effectively, they need to be installed correctly. Let’s look at how to select and install compression couplings to ensure your pneumatic conveying system runs smoothly and efficiently.

How to select compression couplings

Before we cover how to install compression couplings, it’s useful to understandhow to choose the right compression couplings for your pneumatic conveying system. This comes down to three main factors: outer diameter (OD), number of bolts, and gasket material.

Outer diameter

Just as pneumatic conveying pipes and bends come in many different sizes, so too do compression couplings. Your couplings need an OD broad enough to enclose each end of the connecting pipes, but tight enough to form a reliable seal.

Bear in mind, however, that true pipe OD differs from tube OD. Refer to our diameter charts to make sure your measurements are accurate.

Number of bolts

The number of bolts your compression coupling has determines the strength of its seal and its ability to hold your pipes together during operation.

In most cases, manufacturers use 4-bolt couplers. But if your pipes have a particularly large OD or your system pressure is higher than normal, you may need more. If you’re not sure how many bolts your coupling will need, please consult one of our pneumatic conveying specialists.

Gasket material

The gasket in a compression coupling covers the intersection between your connecting pipes. This is how the components form an airtight seal.

There are many types of gasket materialto choose from, each of which offers unique characteristics to suit different applications. Common gasket materials include:

  • Natural rubber: A low-cost, hard-wearing option that delivers excellent performance in many applications. Excellent chemical, temperature, and wear resistance.
  • Silicone: This material offers unparalleled durability and compression set resilience, giving it a much longer working lifespan. It’s also flame retardant, water repellent, and food safe. A great fit for industrial applications.
  • Neoprene: A highly versatile gasket material that offers good all-round resistance to abrasion, corrosion, heat, and water. White neoprene gaskets are FDA-approved as food safe, making them suitable for food and pharmaceutical manufacturing.
  • Metal-detectable silicone: All gaskets wear away over time. But any elastomer fragments that break off from metal-detectable silicone gaskets can be detected by in-line x-ray inspection or metal detection systems. This makes it much easier to prevent contamination.
  • Red rubber: Made from a mix of chemicals, including natural rubber and neoprene. The key benefit of this material is its exceptional heat resistance. Commonly found in heavy industry applications.

How to install compression couplings


  • Thoroughly clean and dry your compression coupling. Grease, dirt, water, and other contaminants will affect installation and the reliability of the seal.
  • Inspect the connecting pipes for burrs and jagged edges. These can damage the gasket, which will compromise the airtight seal. If either is present, replace the pipe.
  • Thoroughly clean and dry the pipes. This prevents the coupling from slipping loose.
  • Check that the partings of the gasket and gasket protector (if present) are approximately 30 degrees on either side of the sleeve flanges gap.
  • Check that the interlocking teeth of the gasket and gasket protector properly mesh with no overlapping edges.


  • Loosen the bolts of your compression coupling.
  • Place the coupling onto the pipe or elbow.
  • Align the pipe with the connecting pipe and butt them together with no apparent gap.
  • Slide the coupling so that it’s halfway onto each pipe. Make sure the gasket isn’t wrinkled, and that the gasket, gasket protector, and internal coupling sleeve surfaces are in full contact.


  • Gradually tighten the bolts in an alternating fashion. Don’t fully tighten each bolt individually, as this can affect the uniformity of the seal.
  • Take care not to overtighten the bolts. This can warp the pipes, compromising the airtight seal or creating leaks where none previously existed.

Buy reliable, tight-fitting compression couplings online

Compression couplings are a vital part of your pneumatic conveying system. So when you need replacement parts, don’t waste time on lengthy sales calls or slow order forms. Simply head over to the PneuComponents online store and order wear-resistant zinc-plated compression couplings in seconds.

Before adding to cart, you can choose the OD, number of bolts, and gasket materials to make sure your new compression couplings fit your system perfectly. Each coupling is quick and easy to install, and includes a conductive grounding strip to protect your equipment from electromagnetic interference. They also include a sideband to improve the strength of the axial hold, meaning the seal remains tight even during higher operational temperatures.

Shop compression couplings now to prevent air leaks, pressure drops, and contamination in your pneumatic conveying system.

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