End portion flow rate regulating apparatus for a paper machine headbox

摘要

A flow rate regulating apparatus of a paper-making machine headbox is compact, can regulate the flow directions of jets of the wet paper stock during operation, and prevents stagnation. Each of tubes at ends of a tube bank disposed upstream of a slice chamber of the headbox for receiving stock from a tapered header includes a first tubular portion consisting of an inlet section having a small inner diameter, a take-out section protruding to the outside of the tube bank, and an outlet section contiguous to the take-out section, and a second tubular portion having a large inner diameter. The inner diameter of each take-out section is larger than the inner diameter of tubes located in the central portion of the tube bank. The take-out sections are provided with a flow rate regulating valve and a flow meter. Alternatively, the end tubes each have a first tubular portion that is straight, and a second tubular portion having a larger inner diameter than and disposed coaxially with the first tubular portion. The inner diameters of the first tubular portions of the end tubes are larger than the corresponding portions of the central tubes. Paper webs having various properties can be made by changing the flow rates of stock flowing through the end tubes with the flow rate regulating valves.