PTFE, PFA, FEP, PVDF Fluoroplastic products industry experts
Selection Points of PTFE Gasket
Classification:
Industry dynamics
Author:
PFA tube little sister
Source:
Dankai
Release time:
2023-01-03
Visits:
In principle, the selection of Dankai PTFE gasket should be based on the working pressure, working temperature, the corrosiveness of the sealing medium and the form of the combined sealing surface. At normal temperature and low pressure, select
Use non-metallic soft gaskets; when medium pressure and high temperature, choose metal and non-metallic combination gaskets or metal gaskets; when temperature and pressure have large fluctuations, choose good elasticity or self
Tight gaskets; in low temperature, corrosive media or vacuum conditions, should consider PTFE gaskets with special properties.
1. It can only be used on low pressure steam pipeline. Because PTFE will become soft when heated, and the pressure will break through.
For example, a company has a medium-pressure steam pipeline. Because the high-pressure gasket did not arrive, the maintenance personnel used PTFE gasket without understanding. It was not a big deal to open the valve slowly. Once the valve was slightly
The slight opening was a little faster. As long as the whole pipeline was filled with PTFE gaskets, it was completely broken. Fortunately, no one was hurt!
2, depends on what kind of steam, temperature, if more than 200 degrees (HG20592 250 degrees), generally we do not choose 4F, as mentioned above will become soft, and 4F
Generally used in corrosive material pipeline, general steam pipeline can choose asbestos rubber gasket, steam pipeline under the condition of meeting the temperature and pressure, if choose 4F
No, it's just a little unreasonable. See HG20592 series standards for details.
3. If the pipe temperature exceeds 180, it is not recommended. For steam, that is, if the pressure reaches 10kg, it is not recommended. Although PTFE does not melt until 220,
If it is more than 100 degrees, it will be soft. For details, you can refer to the PT chart of each product.
Figure 1: PTFE gasket Source: Dankai
In addition, different flange forms and flange surface roughness have a great influence on the sealing effect, especially when non-soft gaskets are used, the large degree of roughness of the sealing surface causes leakage.
One of the main reasons. For example, the knife pattern on the turning flange surface is a spiral line. When using a metal gasket, if the roughness value is large, the gasket cannot block the knife pattern formed by the metal gasket.
A spiral groove, under pressure, the medium will leak out along this groove. Soft PTFE gaskets have much lower requirements on the smoothness of the flange surface, which is due to the fact that
For, it is easy to deform and can block the processing knife pattern, thereby preventing leakage. For soft PTFE gaskets, it is not good for the flange surface to be too smooth, because the boundary occurs at this time.
Surface leakage resistance is reduced. The following are the performance parameters of the PTFE gasket produced by Dankai PTFE.
Performance parameters of PTFE gasket:
Appearance color: white;
Applicable temperature:-180~250;
Applicable medium: ph 0-14;
regular size: 1524mm * 1524mm thick 1.5~5mm.
Scope of application:
PTFE gasket is suitable for sealing parts with severe alternating temperature and pressure. It is a static sealing element for flange connection of pipelines, valves, pumps, heat exchangers, towers, manholes, hand holes, etc.
By changing the tension of the winding steel belt, the density (hardness) of the winding gasket can be changed to meet the needs of various application parts. It is widely used in petrochemical, machinery, electric power, metallurgy,
Shipbuilding, medicine, atomic energy and aerospace industries.
This article is originally created by Teflon's little sister. Welcome to pay attention and take you to grow knowledge together!
Key words:
Selection, gasket, pressure, seal, flange, PTFE, temperature, selection, leakage, steam
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