Abstract: Apparatus provides for testing a fault indicator of the type which has a surge-current detection portion and a settable fault indicating portion and which is widely used in electric power distribution systems. Such a fault indicator must meet certain performance specifications including a maximum allowable reaction-time specification relating to the time required for the detection portion first to detect a surge current flowing in a conductor as a result of a down-line fault and then to set the fault indicating portion accordingly. The testing apparatus of this invention provides for effectively simulating field conditions, and to this end includes current-drive circuitry for supplying a test surge current to the fault indicator under test. Substantially simultaneously with the start of the test surge current, a timing-initiation signal is produced to enable interval-timing circuitry in the testing apparatus. To designate the end of the interval being timed, there is produced a timing-completion signal.

Abstract: Liquid natural gas is odorized with either ethyl or methyl mercaptan by initiallly mixing the odorant with a diluent and then introducing the resultant mixture into the liquid natural gas. It is preferred that the diluent have a freezing point below the boiling point of liquid natural gas. It is theorized that with the diluent the mercaptans either do not freeze or are dispersed sufficiently in the liquid natural gas to reduce the particle size of frozen odorant. In any event, the result is effective odorization of natural gas drawn from a liquid natural gas storage tank regardless of the amount of liquid and gaseous natural gas left in the tank.