Abstract: A two-stage air cleaner with side-by-side elements. The cleaner has a first element (30), a second element (32) which itself may have a safety element (35). The first element (30) is preferably a conical inertial separator having a scavenge outlet (38). The second element preferably employs a pleated filter (50) which receives cleaned air (indicated by arrows 104) which passes through the filter (as indicated by arrows 106) to the outlet tube (56). In an alternative embodiment, pleated filter (50a) may have a reverse taper corresponding to that of the conical inertial precleaner (30a), thereby reducing the size of the housing.

Abstract: An air cleaner and an intake tube having an air permeable portion at one end thereof forms an inner support for the air cleaner, but which is detachable therefrom. In one embodiment, the air cleaner is a single integral unit which is disposed of after use. The unit includes a tubular filter element having an opening sized to receive the intake tube, a shell surrounding the filter element, one end cap sealing and forming a junction between the filter element, shell and intake tube at one end, another end cap sealing and forming a junction between the filter element and shell at the other end and having an aperture through which the intake tube is inserted and at least one air intake aperture in one of the caps. In another embodiment, a centrifugal separator and a dust collector cap which may be emptied from time to time to extend the life of the air cleaner is incorporated therein. The intake tube may also have a right angle bend for side mounted filters.

Abstract: An improved cylindrical two-stage air cleaner in which the overall efficiency of the cleaner is improved by changing the configuration of filtering means therein from a cylindrical one to a conical one, and in which improved structure is included for sealing the cleaner to prevent passage of incoming air to the outlet without being cleaned, and to automatically scrape particulate matter from the inside of the cleaner housing each time a principal filter is changed.

Abstract: A side outlet cyclone separator tube having an improved vortex generating device and an air cleaner incorporating the separator tube are disclosed. The tube includes a conduit member which defines a generally axial passageway for the discharge of contaminants from contaminant laden air. A second conduit member is disposed within the first conduit member and defines an outlet passageway for the discharge of clean air through an opening in the side wall of the first conduit member. The improved vortex generating device includes an elongated hub about which are spaced a plurality of generally helical deflecting vanes. A trailing end of the elongated hub has a curved surface which directs contaminants radially toward the inner surface of the first conduit member.

Abstract: An improved arrangement for responding to reversal in the sense of the ratio between two pressures. In a housing there is located a generally cup-shaped indicator element of resilient, air impermeable material including a slack diaphragm having a central area of augmented visibility and an integral tongue projecting obliquely therefrom. The diaphragm is self-biased in either of two positions, in one of which the tongue conceals the central area, and in the other of which the tongue exposes the area. Pressures to be compared are applied on opposite sides of the diaphragm, and an observation window is provided.

Abstract: A device for monitoring the condition of a filter element, comprising a combined clamping nut and differential pressure indicator. The body of the device is non-circular about an axis to facilitate its use as a wingnut, and has an outer surface and an inner surface through which passes an axial orifice, internally threaded to engage a threaded mounting rod. A differential pressure responsive device of novel design, including a slack diaphragm and an air-permeable translucent screen, is mounted in a further orifice in the outer surface for exposure of one side of the diaphragm to the pressure outside the filter, and a passage in the body connects the further aperture with the inner surface to supply to the other side of the pressure responsive device the pressure within the filter. The combination of such an arrangement with an air cleaner having a safety filter is also a part of the invention, as is the method of monitoring the filter conditions which the structure makes possible.