Fiber diameter measuring device, inorganic fiber sheet producing device, method for measuring fiber diameter, and method for producing inorganic fiber sheet

A method for measuring a fiber diameter measuring a fiber diameter of an inorganic fiber in an inorganic fiber sheet including the inorganic fiber, the method comprising,

• a sampling step of on-line sampling the inorganic fiber from the inorganic fiber sheet by a sampling method capable of sampling a predetermined amount of the inorganic fiber in an entire area of the inorganic fiber sheet;
• and
• a measuring step of measuring the fiber diameter of the sampled inorganic fiber,
• wherein the sampling method comprises on-line sampling the predetermined amount of the inorganic fiber in the entire area of the inorganic fiber sheet as the inorganic fiber remains in conveyance, the predetermined amount of the inorganic fiber in the entire area of the inorganic fiber sheet consisting of an area of the inorganic fiber sheet that is less than the entire area of the inorganic fiber sheet.

A method for producing an inorganic fiber sheet, the method comprising,

• a sampling step of sampling an inorganic fiber from an inorganic fiber sheet by a sampling method capable of on-line sampling a predetermined amount of the inorganic fiber in an entire area of the inorganic fiber sheet including the inorganic fiber;
• and
• a measuring step of measuring the fiber diameter of the sampled inorganic fiber,
• wherein the sampling method comprises on-line sampling the predetermined amount of the inorganic fiber in the entire area of the inorganic fiber sheet as the inorganic fiber remains in conveyance, the predetermined amount of the inorganic fiber in the entire area of the inorganic fiber sheet consisting of an area of the inorganic fiber sheet that is less than the entire area of the inorganic fiber sheet.