Installation steps and key points of threaded joints
1. preparations ‌
Check the accessories ‌ : confirm that the joint type (such as union, quick-connect threaded joint) matches the pipe specification, and check the integrity of the thread and whether the sealing parts (such as O-rings, sealant) are in good condition.
Tool preparation ‌ : It is necessary to be equipped with pipe wrenches, thread threading plates (manual or mechanical), bench vise, etc. When the pipe diameter is ≥50mm, it is recommended to thread in three steps to avoid misalignment.
2. thread processing ‌
Threading operation ‌ :
The pipe end is clamped onto the bench vise, extending approximately 150mm, and aligned with the A-shaped mark and 0-line scale on the threaded plate.
Staged assembly: For 25mm and below, it is completed in one go; for 25-40mm, it is done in two steps; for ≥50mm, it is done in three steps. Each time, the scale of the movable dial is slightly larger than that of the fixed plate.
When nesting, apply force evenly and lubricate with oil. Reserve 2 to 3 turns of slope at the end.
3. connects to install ‌
Quick-connect connector ‌ :
Screw the connector into the output port of the calibration table and press it tightly.
Place the inspected meter into the card slot and tighten it. Then, verify the pressure step by step through the pressure stabilizing valve and the fine-tuning valve (such as 1MPa, 2MPa, etc.).
Union ‌ :
Tighten the bolts symmetrically and gradually to avoid local leakage. When the working pressure is ≥1.6MPa, elastic pressure pads should be added to prevent loosening.
Rubber joints must not be installed beyond the displacement limit, and the force on the bolts should be kept uniform.
4. Sealing and verification ‌
Sealing treatment ‌ : Wrap PTFE tape around the thread or apply sealant to ensure there is no leakage.
Pressure test ‌ : Test multiple pressure points (such as 1MPa, 6MPa) in accordance with the standard, and the indication error must meet the requirements.
5. Special scenarios ‌
Internal thread connection ‌ : if the hardware store does not have a suitable connector, an adapter or a customized solution can be used. Attention should be paid to thread compatibility.
Static cross-connection ‌ : When the resistance of the industrial pipeline flange is greater than 0.03Ω, cross-connection wires are required, especially in flammable and explosive environments.
Precautions
Material matching ‌ : carbon steel joints need to be rust-proof, and stainless steel joints should avoid direct contact with copper parts to prevent electrochemical corrosion.
The standard follows ‌ : industrial joints shall comply with specifications such as MSS SP-83 or GB 50235, and domestic joints shall refer to plumbing standards.