Pre-treatment equipment – silk fabric scouring equipment – scouring tank and barrel

Pre-treatment equipment – silk fabric scouring equipment – scouring tank and barrel

11 Scouring Tank (Scouring Barrel)
The scouring tank is an ancient silk fabric scouring equipment, commonly known as the hanging scouring tank. Because it has the characteristics of simple structure, convenient operation, high scouring and bleaching quality, and is suitable for small batches and multi-variety finishing, it is still a conventional equipment for scouring silk fabrics.
Before scouring, the raw silk first goes through the planning process, which includes five processes: batching, unwinding, folding, stitching and looping, and rod threading and printing. Code folding is to code the raw silk into an “S” shape or a circle, which is called S code or circle code respectively. After the fabric is folded, loop ropes with equal intervals and consistent heights are nailed to one side of the silk edge, that is, thread-stitched loops. The fabric can be threaded on the silk hanging rod piece by piece through the loop rope, as shown in Figure 10-1. The silk hanging rods are arranged on the rod frame in sequence, and the rod frame is lifted vertically by the lifting mechanism, and the raw silk is slowly immersed in the hanging training tank for the impregnation process.

(1) Groove training: Groove training is generally divided into general barrel training and sandwich barrel training, as shown in Figure 10-2.

The hanging training tank generally consists of a training tank, a driving machine, a lifting mechanism, a hanging silk rack, etc.
① General trough: The general trough is a rectangular trough made of stainless steel plates. In the past, it was mostly made of wood or ceramic tiles, also called a ship-shaped trough. The width of the bucket is 120~130cm, the depth of the bucket depends on the width of the fabric, about 140~180cm, and the length depends on the required volume and agreed floor area, generally 220cm, and the volume ranges from 3200L, 4000L, 4600L. There is a direct steam heating pipe at the bottom of the barrel, and a flower board false bottom evenly covered with small holes is installed on the steam pipe to prevent the steam from directly impacting the fabric when heated. According to the requirements of the bleaching process, the arrangement of barrels is generally 7 to 9 in a straight line.
② Sandwiched barrel tempering: When the steam pipe at the bottom of the tempering barrel is heated, the tempering liquid rises, causing the fabric to float, causing scratches and wrinkles, and there is a temperature difference between the upper and lower sides of the tempering barrel. Sandwich barrel tempering can be used. The sandwich barrel training is to install a stainless steel baffle of about 2mm on both sides of the general training barrel 4 to 5cm away from the barrel wall. The lower edge of the baffle is about 20 to 30cm away from the bottom of the barrel, forming an interlayer with the barrel wall. The upper edge of the baffle is submerged under the liquid surface and slightly higher than the upper edge of the fabric. Install a direct steam pipe at the appropriate position on each side baffle and barrel wall. When scouring the fabric, turn off the bottom steam and only use interlayer steam to keep it warm. Since the steam outlets of the interlayer steam pipe are all upward, when the steam is ejected, the liquid is driven into the interlayer from the bottom, overflows from the upper mouth of the interlayer, and flows to the center of the barrel, forming a top-down flow direction. This is exactly the opposite of the bottom-up liquid flow direction when using the bottom steam pipe. However, improper use of the sandwich scouring barrel may cause a “short circuit” in the liquid flow, that is, the liquid flow does not pass between the pages of each piece of fabric, but flows between pieces and closes the pages of the fabric, which in turn affects scouring. Uniformity.
(2) Driving train: The driving train is the operating component in the fabric refining process. It mainly consists of guide wheels, sheaves, gearboxes, tracks, traveling frames and electrical control systems, as shown in Figure 10-3.

The lifting mechanism and front and rear running mechanism of the carriage operate the lifting and front and rear running of the fabric. The former is driven by an electric motor through a worm gear reducer to raise and lower the silk hanging device, while the latter is driven by an electric motor through a worm gear reducer to drive the driving axle to move forward and backward on the track. Both have limit devices to ensure safety.
(3) Cam lifting mechanism: In order to make the fabric degummed evenly in the hanging training tank, a set of symmetrical cam devices are installed on both sides of the training tank. The cam follower is a long lifting plate, and the hanging silk is placed on On the lifting plate, during refining, the motor drives the camshaft to rotate through the reducer, so that the lifting plate drives the silk hanging rack and fabric to move up and down periodically. Generally, the lifting distance is 300~400mm, and the lifting frequency is 4 times/min.
(4) Dehydration machine: To dehydrate silk fabrics, methods such as centrifugal dehydration, water rolling and vacuum water absorption can be used.
① Centrifugal dehydration: Put the entire fabric symmetrically into a circular cage with holes, and use the centrifugal force during high-speed rotation to remove the water. When dehydrating, the fabrics should be stacked evenly around the tumbler. The fabrics should be folded flat in the weft direction, not in half. They should be placed flat and packed sparingly. Dehydration should not be excessive to avoid watermarks. Since the fabric is in a wrinkled state during the dehydration process, it is easy to produce wrinkle marks, so it is only suitable for crepe, georgette and other fabrics that are not easy to wrinkle.

　②Water rolling and rolling: The water rolling and rolling machine consists of a water tank, an expansion roller, a water rolling roller and a transmission device, as shown in Figure 10-4. Water rolling is performed on an open-width water rolling machine. During operation, the two rollers are in natural contact. The fabrics need to be sewn in advance, and are immersed in the clean water pool without pressure in sequence, and then rolled onto the cloth rolling shaft through the nip point in a flat and wrinkle-free manner. Mulberry silk thin fabrics generally do not pressurized water rollers. Prevent the elasticity of the raw silk, which may cause press brake print defects after passing through the water press. Therefore, the water rolling process is actually rolling. Thicker fabrics can be pressurized with water rollers, which are generally used for woven, twill, and satin fabrics. It can prevent wrinkles, but can easily cause defects such as curling and wrinkles.
③ Vacuum water absorption: Silk fabrics often absorb water through vacuum before drying. When the fabric passes through the suction slit of the water suction machine flatly, the negative pressure in the slit tube sucks the water away from the fabric surface and the gaps between the fibers.
The main characteristics of the hanging training process are: simple equipment, low investment, and easy operation; it is suitable for the production of small batches and multiple varieties, with better product quality and higher output. However, because it is an intermittent production, the labor intensity is high. Since the fabric is processed in the form of circle code or S code, the inner and outer layers are not easy to be uniform, especially for finishing.�When silk fabric is heavily twisted, its repair rate is higher.

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