DM&E CRIMPERS

 The stuffing box crimper offers the capability to process volumes of fiber at economical production rates. The tow is gripped between two rolls and forced into the stuffing box. As the box fills, friction prevents the fiber from exiting readily. Back pressure controls the friction. The individual filaments begin to behave as columns and buckle.

 Length, width, and height of the stuffing box ultimately determine the characteristics of the crimped fiber. Very short length stuffing boxes require that the pressure control system exert considerable force on the stuffed fiber. Very long stuffing boxes are sensitive to slight changes in back pressure.

 Width is determined by the amount of fiber to be processed. At the centerline of the stuffing box, the fiber is contained laterally by the fiber on either side. At the edges of the stuffing box, it is contained by the side plates. Within certain limits, if you want to process more fiber, simply make the box wider. If the stuffing box is too wide, the fiber will not fill the box width, and will not be contained laterally. Irregular low crimp is the result. As a guideline for textile and general processing, use 250,000 denier [28 ktex] per inch [25 mm] of width; for specialized fine crimping, use denier as low as 30,000 denier [3 ktex] per inch [25 mm] of width.

 The height of the stuffing box is determined by product characteristics. Tall stuffing boxes induce secondary, and tertiary folding of the crimped fiber. Very short height boxes eliminate this folding but greatly limit throughput as pressure control becomes difficult. General use crimpers have box heights from 1 inch [25 mm] to 2 inches [50 mm]. Crimpers used for fine crimping with a minimum of secondary folding are found with box heights as short as 3/16 inch [5 mm].

 All parts of the stuffing boxes are heat treated stainless steel. The replaceable doctor blade tips are not as hard as the roll material, preventing damage to the rolls in case of accidental contact.

 An emerging requirement in specialty crimping applications is the capability for high speed thread-up. This has led to DM&E's development of easy opening/closing stuffing box technology. On the CL21 Series and CLV21 with the optional stuffing box the outer side plate can be quickly opened and closed to facilitate thread-up.

 The key to maintaining crimp levels with specified characteristics is accurate control of resistance to fiber passage through the stuffing box. Properly sized precision pneumatic regulators and low friction air cylinders are required for most modern crimping applications.

 Cantilevered rolls offer superior stuffing box accessibility to the operator, but aggravate bearing problems by taking most of the nip force on the bearing nearest the roll. Dual bearing supported rolls split the nip load between the bearings on either side of the roll. Because of concerns about bearing life and roll deflection, cantilevered roll crimpers are generally limited to less than 3 inch (75 mm) roll widths. For wider crimpers, the user sacrifices accessibility to gain increased bearing life with dual bearing rolls.

 Rolls may be temperature regulated. Generally water is circulated through the rolls to maintain a suitable surface temperature.

 More information is available on our CL-21 Series Crimper and our WA Series Crimper.