Electric restriction indicator
CA 1094662 A · Owner: Donaldson Company, Inc. · Inventors: Ohta, Tatsuo; Onuma, Minoru; Nakamura, Masayoshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A restriction indicator having a contactless switch device for indicating a restriction in filter elements of fluid filters having an intake side and a negative pressure side. The restriction indicator includes a photointerrupter having a light emitting device and a light receiving device. The light receiving devices provides an electrical signal indicative of increased negative pressure in the negative pressure side.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted January 27, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 27, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.