摘要:
Apparatus for cleaning the surface of small quartz-crystal pieces with aqueous hydrofluoric acid is disclosed wherein the quartz pieces are introduced into a vessel containing a conveying means and conveyed e.g. horizontally in counter-current to aqueous hydrofluoric acid introduced at the opposed end of the vessel. During the washing the quartz pieces are tumbled.
摘要:
To make quartz glass crucibles suitable for drawing of single crystal silicon for electronic semiconductor applications, granular crystalline quartz or amorphous quartz glass is introduced into a rotating hollow mold which has gas-pervious wall regions at the side walls and bottom thereof, for example by having bores extending through a metal mold or being made of porous, sintered material. After introducing the raw material, a heat source, such as an electric arc, is introduced into the hollow mold, causing first sintering and then melting of an inner layer; upon introduction of the hollow mold, a vacuum is applied to the outside of the hollow mold, for example between the housing and the mold body, and, during continued rotation, to draw out any included gases and cause melting-together of vacuoles which, otherwise, might form due to included spaces and gases within the granular filling material. The vacuum is maintained during melting and rotation, heating being interrupted when a sufficienty thick inner wall of molten material has been formed, with an adjacent layer of sintered material leaving, however, granular material immediately adjacent the inner walls of the hollow mold to provide for heat insulation of the molten layer with respect to the hollow mold and protect the surface of the mold. The finished crucible can be ejected by introducing compressed air, rather than vacuum, to the outside of the hollow mold. Suitable vacuum is a pressure of less than 5,000 Pa, preferably less than 1,000 Pa.
摘要:
An apparatus for the oxidative combustion of harmful gases by means of a burner is disclosed. The apparatus comprises a vertically disposed cooling jacket provided with a coolant inlet and coolant outlet which surrounds a combustion chamber. The combustion chamber is connected to and in gaseous communication with a condenser disposed therebeneath. A flushing device is provided in fluid communication with these components, the same being disposed above the combustion chamber and in gaseous communication therewith. A burner is disposed above the flushing device. An electrical igniter is disposed between the flushing device and the burner.
摘要:
An essentially circular header is formed with an interior trough to which a supply duct for cleaning fluid, terminating therein tangentially so that cleaning fluid introduced through the supply duct into the trough of the header and flowing thereinto will be subjected to a swirling motion. The header terminates in a neck portion of substantially reduced diameter which has an outer conically converging surface which fits into a conically diverging surface of a flask, receiver, or other chemical apparatus to be cleaned. Preferably, the neck portion is shorter than the receiving end of the mouth portion of the receiver so that a swirling film of liquid will flow downwardly, by gravity, from the receiver through the neck portion and into the still converging mouth portion of the receiver to be cleaned, to then spread out along the inner walls of the receiver, while still swirling, and efficiently clean the receiver element, without requiring disassembly of the receiver element from remaining portions of the chemical analysis apparatus.
摘要:
Specimens of solid organic substances are decomposed by grinding the specimen to powder having particles of a size smaller than 75 microns, and then compressing the powder specimen. The compressed powder specimen is abraded by means of a scraper, and the abraded material metered out in predetermined amounts for incineration in an injector burner suitable for solids. In this manner, large quantities of specimen material which might contain elements that attack quartz glass can be incinerated without causing damage to the quartz glass burner. The apparatus for decomposing specimens of solid organic substances includes an injector burner that communicates with a powder processing and proportioning device through a flexible tube. The powder processing and proportioning device includes a specimen container for compressed powder, supported by a rotatable fixture to rotate the specimen container. A plug provided in the specimen container, but having radial clearance with respect to the container walls is held by a vertically movable fixture that furnishes movement to the plug along the axis of the specimen container. The scraper for abrading the powder specimen is attached to the plug and is thus movable toward the powder specimen while the container is being rotated. Abraded powder is drawn through the flexible tube to the burner.
摘要:
For the production of a bubble-free vitreous material, and in particular bubble-free vitreous silica, bubbles-containing vitreous material is exposed in a furnace, at a temperature which reduces its viscosity to a value between 10.sup.13.5 and 10.sup.8 Pa.sec, to the omnidirectional pressure ranging from 100 to 3000 bars of a gas which is insoluble in the vitreous material for a period of not less than 10 minutes and is then cooled.