INTRODUCTION:

Vacuum sensors that have a threaded interface (e.g., like those found on Model 215v or Model 200) require threaded pipe connections. Threaded pipe connections are commonly used in vacuum sensors, vacuum pumps and rough-vacuum systems. This type of connection can provide economical, reliable service if properly installed. By following a few guidelines you can use threaded pipe to make connections that should be leak free in pressures down to 10 -4 Torr or better.

However, low quality pipe and cheap pipe fittings are commonly used in rough vacuum systems, which usually results in unexpected leaks down the road. These leaks are tough to diagnose, and most users will rarely suspect the actual pipe or pipe fittings. This just leads to more downtime, more frustration and more cost.

Here are 3 tips on effective sealing:

1. Use sealant prior to assembly.
2. For small pipe joints, use quality thread tape.
3. For large-diameter pipe fittings (> 1″), use a liquid sealant.

To make reliable, well-sealed joints, install pipe fittings using these 5 tips:

1. Use forged (i.e., high pressure) fittings. 
2. Clean pipe ends and fittings before use (use wire brush onmale threads and compressed air on female threads)
3. Use fittings of similar materials when making complex joints (e.g., brass to brass, stainless to stainless, etc.).
4. Avoid breaking joints once sealed and tightened.
5. For best pump performance, use pipe sized to that of the pump inlet.

CONCLUSION:

Properly installing a vacuum pump and its fittings is an art, and worth the additional effort to do it right the first time. Vacuum system leakage can cause unreliability and expense when leakage leads to damage.