带聚四氟乙烯板管托制作问题

Teflon

问：使用聚四氟乙烯板是减小摩擦，用在管托与轴向固定支架之间。
答一：是减小摩擦，我的第一个问题就是想问是一块聚四氟乙烯板与管托的钢制部分摩擦还是两块聚四氟乙烯板相互摩擦？
答二：是两块四氟乙烯板之间滑动，也有用一块四氟乙烯板，一块不锈钢板的。
PTFE slide assemblies are used in piping systems to reduce the coefficient of friction at support locations. Where large displacements are anticipated, it is preferable to use PTFE slides to allow thermal growth of piping system and reduce frictional forces on the anchors or supporting structure.

A typical PTFE slide assembly comprises of teflon pad at the bottom and mating stainless steel plate on the top. The PTFE pad is normally supplied bonded to a carbon steel backing plate. Bonding to steel plate is done by countersunk bolts or by glue. Some manufacturers embed the PTFE pad in a recess to prevent the PTFE pad from getting sheared off from the carbon steel backing plate.

The stainless steel backing plate is supplied with mirror finish and is either supplied loose or tack welded to a carbon steel backing plate. The stainless steel plate is larger than the PTFE pad and is sized to allow the anticipated thermal movements.

In determining the size of the PTFE slide bearing pad the applied loading and the operating temperature has to be taken into consideration. At ambient temperatures a maximum bearing pressure of 60 kgf/cm2 is generally recommended. If loads are high or bearing area is small due to space constraints, glass filled PTFE pads can be used to provide higher bearing pressure."

Glass filled PTFE pads at ambient temperature can provide a load bearing capacity of about 140 kgf/cm2

Virgin PTFE can provide 0.1 coefficient of friction. For glass filled PTFE the friction coefficient is marginally higher at about 0.12.

PTFE is suitable for continuous operation at temperatures up to 150°C. Where the PTFE temperature is likely to exceed 150°C, thermal insulation is provided between the source of heat and PTFE pad.
答三：1. 你可以从国外管架或弹簧支架厂家找到相关资料。  
2. 我上面的回复已经说过了，可以用两块PTFE板的，或者一块不锈钢板，一块PTFE板的。
3  如果是两块纯PTFE板，摩擦系数是0.1，如果是添加了石墨的，摩擦系数是0.12，添加石墨能增加PTFE板的抗压强度。
4. PTFE板的厚度取决于PTFE板跟钢板的连接方式，有粘接的（3mm），有在钢板上开槽嵌在里面的（至少5mm)。
    但要注意如果用粘接的话，必须找到质量可靠的粘结剂。
答四：聚四氟乙烯厚度在3-6mm之间即可。