Irbit Research & Consulting Ag

Walther & Cie Aktiengesellschaft

Sorrento Engineering, Inc.

Illbruck Gmbh Schaumstofftechnik

Werner P Frank

Francis U Hill

Paul F Schoenzart

Fritz Irrgeher

Josef F Irregeher

Rolf Becker

A method of manufacturing polyimide foam filled structures such as honeycomb panels. A polyimide foam precursor is prepared in powder form. A layer of the powder is heated and foamed at the resin condensation temperature and pre-cured to an easily handleable, stiff and inflexible state. A multi-cell, thin-walled structure having open cells along a surface is pressed into and through the foam sheet so that foam pieces fill the cells. The foam is then heated to a final cure temperature at which the foam becomes stable, resilient and flexible. Face sheets may be bonded to the structure to retain the foam pieces in the cells. If desired, the walls of the structure that contact the foam may be coated with an adhesive, such as a liquid polyimide adhesive resin precursor, so that the foam will be bonded to the cell walls when the liquid resin precursor is cured as a necessary result of the final foam cure conditions.

Polyimide foam filled structures

The present invention refers to a sealing element, particularly for the sealing of joints, having a foam element which is elastically expandable with delay as a result of impregnation and a substantially air-tight cover. In order to obtain improved tightness of the seal while retaining the advantageous ability of use of such a sealing element, the cover forms an open region within which the foam element is exposed.

Sealing element

A method of making polyetherimide foam precursors and flexible polyetherimide foams having improved specific tensile strength, resistance to high temperatures and flame, low density and flexibility at both high and cryogenic temperatures. 4,4'-oxydiphthalic anhydride (ODPA) is reacted with an alcohol to produce a diester, which is then reacted with a suitable monomeric polyamine such as meta phenylene diamine to produce a precursor. This material is dried to a solid block or powder. Upon heating, foaming occurs, resulting in a fine celled white friable mass. The foam is cured by heating for a suitable period and is ready for use.

Polyetherimide foam precursors and foams having improved physical

The hoppers of several dust precipitators are connected to a common readily accessible monitoring station by discrete conduits each of which has a first open end at a preselected level in the respective hopper, a second open end at the monitoring station and an intermediate portion extending above the corresponding preselected level. Suction which normally prevails in the hoppers tends to maintain closed pivotable flaps for the second open ends of the conduits. If the dust in a hopper accumulates to or rises above the respective preselected level, the corresponding flap is opened by a counterweight and such movement of the flap entails the generation of a signal which is used to evacuate dust from the corresponding hopper and/or to actuate an alarm for the convenience and attention of the persons in charge.

Apparatus for ascertaining the level of flowable material in dust

Foam material sound absorption

The operation of one or more full-size electrostatic filters for removing solid impurities from gaseous carrier media is regulated automatically as a function of variations of breakdown potential of a miniature electrostatic filter which is installed in the path of the contaminated gaseous carrier medium. The regulation is such that the potential which is applied to the corona discharge electrode(s) of the full-size filter(s) is very close to but continuously below the breakdown potential. This eliminates the periods of idleness of the full-size filter(s) by preventing arcing because the applied potential does not reach the breakdown value at which the electrostatic field collapses.

Growing community of inventors

Gladbach, Germany

Werner P Frank