How to deal with the leakage of hydraulic connections

Date:14 Mar 2020

Use reliable connectors Tapered threaded connectors (su […]

Use reliable connectors
Tapered threaded connectors (such as NPT and BSPT) are the most unreliable connectors for high pressure hydraulic systems because the threads themselves provide a leak path. The threads are deformed when tightened, so any subsequent loose or tightened connections increase the possibility of leakage.

Connectors incorporating elastic seals, such as UN-O-rings, BSPP, ORFS and SAE four-bolt flanges, have excellent sealing reliability.

Therefore, for leak-free reliability, replace the pipe threaded connector with an elastomer-sealed type whenever possible.

A flare seal made by Flaretite consists of a stainless steel stamped part with concentric ribs containing a pre-applied sealant. When tightened, the ribs are pressed between the two faces of the joint, eliminating any misalignment and surface defects. The combination of compression on the ribs and sealant ensures a leak-free connection.

Short-circuit vibration
Vibration can stress hydraulic lines, cause fatigue, and affect connector torque. If significant vibrations occur, the root cause must be addressed. This may involve installing hoses and / or rubber mounting blocks to eliminate vibration "bridges" between hydraulic power units, fuel tanks, and valves. Also, always ensure that all conductors are properly supported.

Correct torque
A common cause of leaks in 37-degree flared joints and compression fittings is incorrect torque. For flared joints, insufficient torque can cause insufficient seat contact, while excessive torque can damage tubes and connectors through cold work. In the case of crimping, the wrong torque can cause too much or too little "squeezing" on the ferrule. For best seal reliability, consult the torque recommendations of the connector manufacturer and apply as directed.

Keep the machine cool
The advantages of hydraulic connectors are outlined, so that the operating temperature of most sealing compounds not exceeding 85 degrees Celsius will lead to a doubled life span. Also, a single sufficiently large overheating event can damage all seals in the hydraulic system, resulting in large leaks.