Abstract A pyrometric sensor using a thermistor which is highly resistant to vibrations and heat, comprising a heat-sensing unit formed by inserting a pyrometric thermistor into a metallic protecting tube, connecting lead wires of the thermistor to the protecting tube and a center electrode, and packing a heat-resistant insulating material into said protecting tube. The section of the heat-sensing unit where the thermistor is not located is partly inserted into a hole of an adapter for receiving the protecting tube, an insulating tube is held within the adapter, an upper electrode is secured to the insulating tube by a flange of the electrode itself and a lock nut in thread engagement with a threaded part of the electrode, and the center electrode of the heat-sensing unit is connected to said upper electrode.
The pyrometric sensor of claim 1 further including: an adaptor having a first receiving opening for receiving an end of said protecting tube remote from the thermistor and the central electrode passing through an opening in said adaptor; an insulating tube held within a second receiving opening at an opposite end of said adaptor remote from the protective tube, a packing washer disposed within said second receiving opening for holding the insulating tube in place and a metal washer disposed in a groove in the second receiving opening for holding the packing washer in place; a flange for the center electrode, adapted to be engaged with the insulator and a portion representing the end of the center electrode, the flange extending outwardly past the extreme end of the second receiving opening, and locking means for securing the end of the electrode for maintaining the entire structure securely.
Claim 2
Dependent Claim
22 words
The pyrometric sensor of claim 2 wherein the end of the electrode is threaded and the locking means is a lock nut.
Claim 3
Dependent Claim
69 words
The pyrometric sensor of claiM 1 wherein the heat resistent material is selected from the group consisting of: magnesium oxide; refractory mortar; castable refractories; burned aluminum oxide; sealing glass powder; crystalizing glass powder; alumina ceramics; and a mixture of 99 to 70 weight percent of alumina oxide powder and 1 to 30 weight percent of a metallic oxide powder selected from the group consisting of CaO, SiO2 has MgO.