Embodiments of the present invention relate to apparatuses and methods for leakage detection for installed filters of a multi-filter containment enclosure, without requiring disassembly of the multi-filter containment enclosure. The containment enclosure of the present invention comprises a filter housing. The filter housing comprises one or more filter compartments for housing at least a first filter and a second filter. The filter housing comprises at least one port which is operatively coupled downstream of the first filter and upstream of the second filter. Typically, the at least one port allows for leak testing of the first filter and the second filter without having to remove the first filter and the second filter from the containment enclosure.

A particulate matter detection circuit includes, a negative resistance circuit that couples to a first antenna inserted in a housing accommodating a first filter that filters an exhaust gas, couples to a second antenna inserted in the housing via a matching circuit that performs an impedance matching and a second filter that narrows the frequency band of a passing signal, and oscillates at a resonance frequency of the housing, and a detection circuit that outputs a voltage value corresponding to a signal strength of a radio wave received by a third antenna or the second antenna inserted in the housing. The resonance frequency of the housing varies depending on an amount of matter adhered to the first filter.

A method of integrity testing a porous material is disclosed, providing a porous material suitable for filtration to be tested, said porous material having a first surface and a second surface; wetting said porous material with a wetting liquid; providing a gas stream comprising at least first and second gases humidified with said wetting liquid below the saturation vapor pressure of said wetting liquid and wherein said humidified gas stream has a humidity of 50-99%; introducing said gas stream to said first surface of said porous material; causing said first and second gases to flow through said porous material; measuring the concentration of at least one of said first and second gases in the permeate stream exiting said second surface of said porous material; and comparing the measured concentration to a predetermined concentration.

A honeycomb body having a porous ceramic honeycomb structure with a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels. A highly porous layer is disposed on one or more of the wall surfaces of the honeycomb body. The highly porous layer has a porosity greater than 90%, and has an average thickness of greater than or equal to 0.5 m and less than or equal to 10 m. A method of making a honeycomb body includes depositing a layer precursor on a ceramic honeycomb body and binding the layer precursor to the ceramic honeycomb body to form the highly porous layer.

Methods for analyzing an accumulation of particles on a filter membrane involve analyzing comprise the particle accumulation in an optical analysis system using a light microscope, and then analyzing the particle accumulation in an SEM-EDX analysis system using a scanning electron microscope and energy-dispersive X-ray spectroscopy. In order to simplify and accelerate the testing of the filter membrane both in the optical analysis system and in the SEM-EDX system, the filter membrane is subject to a preparation which includes: (i) fixing the particles to the filter membrane, (ii) coating the particle accumulation with an electrically conductive coating which is produced from a conductivity solution that contains an ionic liquid, and (iii) holding the filter membrane flat or pulling the filter membrane taut.

A method of determining a flow resistance across a particulate filter located downstream of an internal combustion engine in an exhaust system. The method comprises measuring a first differential pressure across the particulate filter, measuring a second differential pressure downstream of the particulate filter, determining a pressure ratio of the first differential pressure and the second differential pressure, and from said pressure ratio, determining a flow resistance across the particulate filter. The second differential pressure is measured across a selective catalytic reduction system.

A method for calculating a service life of a filter gauze is applicable to an air cleaner. The method includes: according to data of a rotational speed of a fan and an airborne particle concentration, calculating an outlet air velocity, and a blocking ratio of the filter gauze; and further calculating a remaining service life of the filter gauze. In this way, a user can be more accurately informed of the remaining service life of the filter gauze, and instructed to change the filter gauze at the most appropriate time.

The present disclosure relates to a process for testing the integrity of membranes in a filter module. Specifically, the process is applied to filters for extracorporeal blood treatment, in particular, filters comprising both filter membranes and particulate material.

A particulate filter inspection system for a particulate filter includes a compressed air source, a primary conduit, a controller, a probe, and a gauge. The compressed air source is configured to draw air from an air source. The primary conduit is configured to receive air from the compressed air source. The probe is coupled to the primary conduit and communicable with the controller. The probe is configured to interface with a face of the particulate filter to provide air to only a sector of the particulate filter. The gauge is configured to determine a pressure of air within the primary conduit when the probe is providing air to only a sector of the face of the particulate filter. The controller is configured to receive the pressure from the gauge, compare the pressure to a target upper pressure, and provide an indication that the particulate filter is dirty if the pressure is not lower than the target upper pressure.

A method of integrity testing porous materials that is non-destructive to the material being tested. The method includes humidifying the inlet gas stream to minimize or prevent the porous material from drying out. The inlet gas stream includes at least two gases, wherein one of the gases has a different permeability in liquid than the other, such as oxygen and nitrogen. The permeate gas stream may be subjected to a driving force such as reduced pressure to increase the flow of gases and reduce test time. Multiple porous materials can be integrity tested at the same time, such as by manifolding a plurality of them together. The integrity test is capable of detecting the presence of oversized pores or defects that can compromise the retention capability of the porous material.