Sealing pneumatic and hydraulic threads

Sealing pneumatic and hydraulic threads is a key aspect of maintaining the efficiency and safety of industrial systems. Proper execution of this process requires the use of appropriate techniques and materials tailored to the specific characteristics of the system in question. Below is a detailed description of professional methods for sealing threads in pneumatic and hydraulic systems.

Thread Sealing Methods

Flax or hemp packing

A traditional method for sealing threads, particularly in hydraulic systems, is the use of flax or hemp packing. This process involves the following steps:

1. Preparing the thread surface—lightly roughening the thread surface to improve adhesion.
2. Application of sealing paste (e.g., Bisan) to the thread.
3. Carefully wrapping the thread with packing in the direction of threading, starting from the edge of the fitting.

The advantage of this method is the ability to seal even with a small gap between the threads and flexibility in setting the connection angle.

Teflon tape (PTFE)

Teflon tape is a modern alternative to packing. The application procedure includes:

1. Cleaning the thread surface.
2. Winding the PTFE tape in the direction of the thread’s rotation.
3. Tightening the fitting to the correct torque.

PTFE tape provides good sealing and is resistant to many chemicals.

Anaerobic adhesives

Anaerobic adhesives, such as Weiconlock AN 305-42, are recommended for sealing threads in pneumatic and hydraulic systems. Application process:

1. Clean and degrease the thread surface.
2. Apply a thin layer of adhesive to the thread.
3. Install the fitting with the appropriate tightening torque.

Anaerobic adhesives cure in oxygen-free conditions, forming a durable and vibration-resistant seal.

Technical specifications and advantages of anaerobic adhesives

Anaerobic adhesives, such as Weiconlock AN 305-42, have the following characteristics:

• Single-component chemical formula
• Rapid polymerization upon contact with metal
• High resistance to temperature fluctuations
• Good resistance to dynamic loads and vibrations
• Precise dispensing

Selection of sealing method

When selecting a sealing method, the following should be considered:

• Type of working medium (gas, water, hydraulic oil)
• System operating pressure
• Operating temperature
• The material from which the fittings are made
• Thread size
• Requirements for future disassembly of the connection

Thread sealing procedure

Regardless of the method chosen, professional thread sealing should include the following steps:

1. Visual inspection of the thread for mechanical damage
2. Thorough cleaning of the thread surface to remove contaminants and residues from previous sealants
3. Degreasing the thread surface with a suitable solvent
4. Application of the selected sealing compound in accordance with the manufacturer’s instructions
5. Installing the fitting while maintaining the correct tightening torque
6. Checking the connection for leaks after installation

Maintenance and Diagnostics

Regular inspection of threaded connections is critical to maintaining system tightness. If a leak is detected, you should:

1. Identify the source of the leak
2. Depressurize the system and disassemble the leaking connection
3. Clean the threaded surfaces
4. Re-seal the connection using the appropriate method
5. Perform a leak test after reassembly

The use of professional thread sealing methods in pneumatic and hydraulic systems is essential to ensure trouble-free operation of industrial installations. Proper execution of this process requires not only technical knowledge but also experience and diligence. Regular maintenance and a quick response to detected leaks help prevent serious failures and production downtime.