DISTANCE MEASURING APPARATUS, DISTANCE MEASUREMENT UNIT, AND DISTANCE MEASURING METHOD

To provide a distance measuring apparatus capable of easily and quickly measuring a distance from an opening of a reaction tube to granular solid matters with which the reaction tube is filled, a distance measurement unit, and a distance measuring method.SOLUTION: A distance measuring apparatus 10 is used to measure a distance from an opening 911 formed at an end part in an axial length direction D2 of a reaction tube 910 to granular solid matters 920 of a catalyst and/or inactive substance with which the reaction tube is filled in non-contact. The distance measuring apparatus has: a length measuring device 100; and a guide member 200 connected to the length measuring device. The guide member has a part to be inserted through an opening of at least one of a plurality of reaction tubes and/or the guide member at least has a part having a surface in contact with an end part of the opening of at least one of the plurality of reaction tubes and a part that can contact a part of a wall surface of at least one of the plurality of reaction tubes.SELECTED DRAWING: Figure 3 【課題】反応管の開口から、反応管の内部に充填された粒状の固形物までの距離を簡易かつ迅速に測定することが可能な距離測定装置、距離測定ユニット、および距離測定方法を提供する。【解決手段】距離測定装置１０は、反応管９１０の軸長方向Ｄ２の端部に形成された開口９１１から、反応管の内部に充填された触媒および／または不活性物質の粒状の固形物９２０までの距離を非接触に測定するために使用される。距離測定装置は、測長器１００と、測長器に接続されるガイド部材２００と、を有する。ガイド部材は、複数の反応管の少なくとも一つの反応管の開口から内部に挿入される部位を有し、および／または、ガイド部材は、複数の反応管の少なくとも一つの反応管の開口の端部に接する面を有する部位と複数の反応管の少なくとも一つの反応管の壁面の一部に接触可能な部位とを少なくとも有する。【選択図】図３