Abstract: An automatic product (12) expiration alert device comprising a product (12) having a predetermined useful life and a package (14) covering at least a portion of the product (12). The act of opening the package (14) automatically energizes a timing device (16) to begin measuring the product (12) life. The timing device (16) has an inactivated an activated state. An initiator (18) is located proximate the package (14) and product (12). The initiator (18) is operably connected to the timing device (16) and movable between a first position and a second position when the package and timing device (16) are moved apart from each other The timing device (16) remains in the inactivated state when the initiator (18) is in the first position and the timing device (16) is in the activated state when the initiator (18) is in the second position. A signal alert (20) is in communication with the timing device (16) so that it produces a signal in response to the timing device (16) when the product (12) life has expired.

Abstract: A filter alert device (10) for use in forced air systems (50) used to distribute conditioned air comprises an indicator that operates with an air filter (30) supported by a register (50). The filter (30) and filter alert indicator (16) have cavities in communication with at least a portion of the air passing through the filter (30). The air pressure varies in response to the flow through the filter (30) and exceeds a predetermined pressure when the air is unable to flow through the filter (30) at desired pressure levels and the life of the filter has been exceeded.

Abstract: The present invention is directed to a membrane filter having predetermined controlled porosity and to the method for making such a membrane filter. The membrane filter has a plurality of pores, with each of the pores having a predetermined size from top to bottom located at predetermined locations across the membrane filter. The pores each have a tapered configuration with the larger opening at the surface of the membrane filter and the smaller opening at the bottom of the membrane filter. This tapered configuration permits pre-filtering. The membrane filter is made by a method which utilizes a probe having a tapered piercing tip that pierces the membrane to form the pores. Preferably, a plurality of probes are nested together so that a predetermined number of pores can be made with one reciprocation. If additional pores are needed for increased flow rate, the bundled probes can be laterally shifted or jogged with respect to the membrane material and further pores formed.