Membrane permeation processes to produce oxygen-enriched gas from atmospheric air are improved by feeding the air to membrane cells divided into two groups, independently withdrawing the permeate output from the two groups of cells into two conduits containing restrictions, and referencing the pressure of one output against the other. A subsequent imbalance of pressure between the two permeate outputs indicates a membrane leakage in one of the two groups of cells.

Process for producing oxygen-enriched gas

The operative within a work cab is protected from a polluted atmosphere by provision on the cab of an air pressurizer/conditioner which comprises an air treatment unit and a turbo-fan assembly. The air treatment unit (12) takes the general form of a parallelepipedic box having on one of its front faces a suction orifice 10a extending over the greater part of this face to allow access to the front face of the coarse filter element (15) and to the front face of the fine filter element (16), these said faces being attached mechanically and without a leak to an intermediate leak-proof frame. The turbo-fan assembly (19) is located inside the box downstream of the filter elements (15, 16 and 17) so that the air passes through the said filter elements as a result of suction and is delivered purified into the working cab (11) through a diffuser (24). A pressurizer is provided with a pressurization monitoring device and a toxicity detector (32) for the air forced into the cab.

Air pressurizers/conditioners especially for work cabs in a polluted atmosphere

A filter condition responsive apparatus for a range or stove vent system containing a first filter for filtering grease and a second series connected filter for the removal of odors. A first pressure responsive device responds to the pressure drop across the grease filter to provide an output indicative of the collection of grease on the filter. A second pressure responsive device responds to the pressure drop across the second filter to provide an output indicative of the flow of air through the filter. The output of the two devices are connected to provide an indication of the condition of the grease filter independent of any change in air flow.

Filter condition responsive device compensated for changes in medium flow

This exhaust gas filter includes a cylindrical body formed from a fibrous filter material which is supported by a central core member attached to a base member. The body is adapted for insertion into an automobile tail pipe and the filter is attached to the tail pipe by means of a clamp provided by the base member. A removable cellephane cover is provided to facilitate installation and handling.

Exhaust gas filter

A method and device for monitoring the condition of at least one filter arranged in a flow path of a ventilator. Flow measurement signals are obtained from a first flow meter and a second flow meter and pressure signals are obtained from a first pressure meter and a second pressure meter. When a filter in the inspiratory section of the ventilator is to be tested, flow through the filter and the drop in pressure across the filter are determined from the pressure measured by the first pressure meter and the second pressure meter. If the drop in pressure in relation to the flow lies within predefined limits, the filter is deemed to be serviceable. In a corresponding manner, another filter in the expiratory line can be tested, wherein flow through the filter is determined by the second flow meter.

Method and device for monitoring the condition of a filter in a ventilator

In a system for measuring the pressure in a conduit or line in which finely divided solids are transported in gas, the single inlet of the primary measuring gauge is connected to the transport line by a tube whose outlet is preceded by a first filter. A differential pressure limit gauge has one inlet connected to the line by a similar filter containing tube and its other inlet connected to the outlet of the first tube so as to measure the pressure drop across the first filter and thereby indicate when either filter may be clogged. The differential gauge produces an alarm signal to indicate filter condition.

E Schempp

Papers

Pressure measurement apparatus for pneumatic material transport lines