This invention relates to a device suitable for the transportion and delivery of highly pure liquid chemicals capable of reacting with air.
There are many instances when chemicals having a very high purity are required. If these chemicals are capable of reacting with constituents of the air, for example, oxygen or atmospheric moisture, it becomes necessary to ensure that these chemicals cannot come into contact with air, either during transport and storage, or when they are emptied out.
For the manufacture of light transmitting fiber in particular, liquid chemicals, for example, silicon tetrachloride, phosphorus oxychloride, boron tribromide and germanium tetrachloride, are required in high purities. The presence of transition elements from the 4th period (vanadium to copper) in these liquid chemicals is particularly undesirable. Unfortunately, contamination with heavy metals, for example, iron, chromium and nickel, becomes virtually unavoidable when prior art stainless steel containers are used since, as a result of hydrolysis with atmospheric moisture which is virtually impossible to prevent during filling and emptying, hydrohalic acids are formed which attack the stainless steel container.
For this reason, these chemicals are often delivered in sealed glass ampoules. These glass ampoules have the disadvantage, however, that only a relatively small amount can be filled into each package and the emptying of the packages can only be carried out through very complicated procedures of sealing out air. A quartz container can also be used for this purpose, which includes fused-in connecting tubes. However, this type of container is extremely expensive and can therefore be manufactured for only relatively small quantities. Further, the cleaning of the container which is necessary before refilling, is very difficult since a sufficiently large opening into the container is generally not provided.
USPTO Backgrounds
USPTO Backgrounds