Analysis of the use of PTFE packing

The PTFE packing is made of pure polytetrafluoroethylene resin as raw material, made of raw material film first, and then weaving the packing by rifling, without PTFE emulsion and lubricating grease. Because it is made of solid woven and flexible adjustability, so with the shaft, stuffing box can be a good match, has excellent corrosion resistance, good self-lubricating and anti-adhesive. The PTFE has no other additives and can be widely used in valves, pumps, etc. which have a relatively high degree of cleanliness such as food, paper and chemical fiber, and have strong corrosive media.

Precautions before installing PTFE packing:

Removing old packing Checking the stuffing box is the key to early installation preparation. Before packing, use the special tools to remove all the old stuffing. Wipe the stuffing box clean to observe any defects in the stuffing box, such as damage and eccentricity. The damaged valve stem, bushing and stuffing box can affect the performance of PTFE packing. Check if other parts can be applied. Replace all broken parts.

Sealing and installation of sealed PTFE packing Note the details:

1. Select the appropriate PTFE packing and cut the required length of PTFE packing ring with cutting machine. If there is no PTFE packing cutting machine, then according to the PTFE packing length L = (shaft diameter d + PTFE Packing width s) X1.07X 丌 to cut, generally rotating shaft, cut with 90 ° straight, valve with 45 ° cutting. Never attempt to determine the length with PTFE packing around the stuffing box. Or PTFE packing around the same as the stem. On a tube, it is pressed tightly, but PTFE packing cannot be stretched. Then cut it into rings and check that it fills the space correctly and that there are no gaps at the interface.

The rings can then be cut using standard rings as standard aramid fiber packing. If these finished products are finished on the plane, if the PTFE packing is soft or easily deformed, a small band can be made from the sample ring and then the remaining packing ring can be made according to the string.

2. When the PTFE packing is used in the valve, the PTFE packing section is the same as the space of the valve. It is better to use the pre-pressing ring: When used in the pump, the PTFE packing cross section and the valve space (about 0.3mm) -0. 6mm) Provides a leakage gap between the shaft and PTFE packing for lubrication and heat dissipation.

3. Install one ring of packing at a time. Make sure that the price of the high-water base plate is not covered with dust or other debris. If required, the packing ring should be lubricated with the same clean lubricant used on the stem. Install staggered rings 90° apart. The ring slowly pulls open in the axial direction.