Packing selection for Besa valves in Italy

Packing selection for Besa valves in Italy

BESA's main product lines:

139 threaded connection safety valve

240F threaded connection safety valve

249 threaded connection safety valve

130 flange connected safety valve

240 flange connected safety valve

250 flange connected safety valve

260 flange connected safety valve

280 flange connected safety valve

290 flange connected safety valve

Packing selection for Besa valves in Italy

Italian BESA safety valve,Packing is a filling material for dynamic sealing ，Used to fill the space of the stuffing boxPrevent the medium from passing through the valve stem and packing Box space leakage .Packing seal is one of the key parts of valve products ，To achieve good sealing effect ，On the one hand, it is the filler material Its own material 、The structure needs to adapt to the working conditions of the medium； On the other hand, it is the reasonable installation of fillersInstallation method and from the stuffing box Structurally considered to ensure reliable sealing .In more demanding situations ，Corrugated pipe sealing can also be applied.

① Requirements for the filling material itself： a. Reduce the friction between the packing and the valve stem； b. Prevent the corrosion of the valve stem and packing box by the packing material eclipse； c.The need to adapt to the working conditions of the medium.

②Types of commonly used fillers： Introduction of foreign materials on varieties used under various working conditions40 other species ，And in general valves，often use of No pass how many plant or ten how many plant.a. fill material type.namely oak glue stone cotton fill material： XS250F、XS350F、XS450F、XS550F； Oil immersed asbestos packing： YS250F、YS350F、YS450F； PTFE impregnated asbestos packing； Flexible graphite weavingWeaving and filling material ，According to the different reinforcement materials, they can withstand different temperatures 300℃ The450℃ The600℃ The650℃ The850℃； PTFE woven filling material；Half metal braided filler ，Clamped with stainless steel wire、Copper wire with asbestos as the core ，Exterior with copper wire clip、stainless steel wire、Monel silk ，Woven with asbestos thread of Inconel wire ，According to its purpose, graphite is used on its surface、mica、Molybdenum disulfide lubricant treatment ，also Twisted copper foil coated with graphite and lubricated with asbestos as the core .b. 成形填料 .The filler formed by compression molding ，Its varietyhave： nylon；rubber； Polytetrafluoroethylene； Fill polytetrafluoroethylene（ Enhanced polytetrafluoroethylene），The reinforcing material is glass fiber， generally8% ~ 15% fiberglass ，JB/T 5209—1991Filled with polytetrafluoroethylene： Polytetrafluoroethylene+ 20% Glass fiber Wei+ 5% MoS2 、Polytetrafluoroethylene+ 20% fiberglass+ 5% graphite； Flexible graphite ring.

③ Installation precautions： a.When the filler type filler is cut, it appears as 45°incision 、During installation, the notches in each circle are staggered 120 ° .b. Above When using polytetrafluoroethylene molded packing under pressure ，Pay attention to the characteristics of cold flow .c.Individual use of flexibilityThe sealing effect of graphite ring is not good， Should be woven with flexible graphite filler or YS450（ Depending on temperature conditions） combined use ，Install a flexible graphite ring in the middle of the stuffing box ，both ends Install woven fillers ，It can also be installed in compartments ，That is, a layer of flexible graphite ，One layer of woven fillingmaterial ，You can also place a spacer ring in the middle of the packing box， Install two sets of composite packing materials on the top and bottom of the partition ring respectively .d.Graphite on valve stem 、The wall of the packing box is corroded ，Corrosion inhibition should be selected during use The root of the agent .e.Flexible graphite in aqua regia 、concentrated sulfuric acid 、Concentrated nitric acid and other media are not suitable .f.Dimensional accuracy of stuffing box 、surface Roughness value ，The dimensional accuracy and surface roughness value of the valve stem are the key factors affecting the sealing performance of the formed packingkey.