Drying, whether it be of loose fibre, yarn or fabric, is one of the most energy-intensive operations in the dyeing and finishing area.

Moisture is generally accepted as one of the most important factors affecting the processing of fibres, yarns and fabrics. This rings true for both natural and man-made fibres, albeit it is often more significant for natural fibres, as they tend to be more hygroscopic.

The purpose of the drying operation is to drive off the moisture within the fibre, so that when the product (whether it be loose fibre, yarn or fabric) exits the dryer it is at the desired moisture content (or regain).

Each process has different requirements for the moisture content as the product exits the dryer. In some processes the moisture content has no bearing at all, for example heat setting of fabrics. In this process the object is to drive off most of the moisture early in the drying process and then have the material maintain a certain surface temperature for a certain period of time to ensure adequate “setting” of the material.

In other processes, the moisture content of the product as it exits the dryer is critical. To avoid the problems that can be caused by moisture-content variations, most processors tend to over-dry, as this tends to be the “safe” option from a production and quality perspective. But it results in a significant waste of energy. For wool fibre a good “rule of thumb” is that between 15% and 10% regain, for every 1% you over-dry you are wasting 2% to 3% in energy!

Processors without accurate on-line moisture-control systems typically over-dry by 3 to 4% (or more), thus wasting 10% or more in energy. How much does 10% of your drying-energy costs equate to over a year? This could impact significantly on your bottom line – studies have shown that a 1% saving in energy can equate to an improvement in bottom line profits by 10% or more.

Although over-drying is referred to above as a “safe” option from a quality perspective, over-drying can cause quality issues too (fibre damage, static problems, etc). Also, if fibre is sold based solely on weight, you are giving away fibre when you over-dry!

Moisture measurement and control systems are available to ensure that the product moisture content is maintained at the desired level at the exit of the dryer. These systems, such as the Streat Instruments DRYCOM Moisture Control System, continually monitor the moisture of the product at the exit of the dryer and manipulate either the energy supply to the dryer, or the dryer speed, to maintain the product moisture at the desired level. This allows the “safety margin” to be reduced to a much tighter window of moisture-content levels, thus affording the benefits of significant energy and productivity savings.

In response to requests from high-value knitwear processors in Scotland, Streat developed the DRYCOM Tumble Dryer Controller, which is easily retrofitted to existing dryers. By ensuring the garments are removed from the dryer at precisely the right time, product quality (handle and shelf appearance) are optimised and processors benefit from reduced energy and increased productivity.

With a typical payback period of between 6 and 12 months, Streat DRYCOM systems provide processors with a significant opportunity to reduce energy costs, improve productivity and efficiency, and enhance their competitive edge.

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Manufacturers of both nonwovens and traditional textiles are becoming increasingly aware of the importance of moisture management during processing. Its well known that fibres perform differently during the carding, lapping, needing and spinning processes. Finding and maintaining the optimum moisture content provides clear benefits in both processing performance and product quality.

“Over-dry material creates static problems,” says Jim Herbison, Managing Director of Streat Instruments. “It can also reduce fibre strength, resulting in excess fibre breakage, increased drop out and reduced yields. On the other hand, a product that is too wet blocks fibre transports, causes roller laps and can lead to the build up of bacteria.” Streat Instruments moisture systems are designed to assist users in optimising production conditions in order to maximise productivity, quality, operating efficiencies and profitability in the nonwovens and textiles industries. Over the last three decades he New Zealand-based company has earned international recognition as a premier manufacturer and supplier of moisture management technology.

New App increases control and flexibility

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The new Drycom Connect combines well proven Streat control technology with a dedicated smart-phone and tablet app, which allows operators to view moisture and associated production data from their production plants in real time, at any time, from anywhere. “The Drycom Connect App is a valuable management tool, empowering users to monitor system data remotely,” says Herbison. “Having a mobile option provides an increased level of control as well as peace of mind.” The App can keep track of multiple systems within the plant and can be integrated with data from fibre weight control systems by Streat’s sister company Garnett Controls.

Sustaining quality with minimal energy consumption

Drying is one of the most energy intensive operations in textile mills. Streat Drycom empowers processors to reduce energy usage by optimising the drying process.
Drycom ensures consistent moisture by continuously measuring the moisture of the fibre, yarn, nonwoven web, or other product outputs at the exit of the dryer.

“Drycom automatically controls the energy and/or speed of the dryer to maintain the desired level of moisture,” adds Herbison. “In addition to ensuring consistent moisture content, the productivity gains and energy savings provided by our systems are considerable.”

Hundreds of Streat Drycom systems are already providing users in over 40 countries with the tools they need to operate sustainably, optimise production processes and maximise productivity, quality, operating efficiencies and profitability.

In processing areas such as opening and blending, carding, and web forming, plant humidity control is not enough to ensure optimum moisture conditions. Micro-climates within machinery often dry the fibre, making downstream processing difficult or impossible. It’s not uncommon for plants to run at high humidity levels (up to 70+ % RH) in order to drive fibre moisture content up to manageable processing levels. High humidity creates an uncomfortable environment for workers, high energy costs, and potential machinery damage.

Drycom measures the fibre directly. Moisture can them be managed in a manner appropriate to the process, such as targeted moisture application by precision spraying devices. Experience in all types of natural and man-made fibres has enabled Streat to build a portfolio of application-specific technologies to ensure sustainable production.

The Superwash process is an application that has special requirements to which the control system must conform to ensure the product quality is maintained to the desired level. Streat Instruments Moisture Measurement and Control systems have been applied to Superwash Plants around the world and we were involved with the initial Superwash development at the IWS and then the Woolmark Company. Jimmy Jackson*, widely regarded as the expert in the area of easy-care wool products and processes, recommends Moisture Measurement and Control for Superwash Lines as detailed below:

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Moisture management & control is important in the Superwash process to save energy and control the regain in the sliver so that subsequent mechanical processing is trouble free, and also maintain good wool colour etc. The additional advantages for a Superwash plant are ensuring that the resin is evenly and constantly cured. (i.e. If the Superwash wool is still wet or damp, and hence the resin is not fully cured, then curing will take place later in the bale after packing resulting in the fibres sticking together and the customer receiving hard tops, which will need to be backwashed at additional expense before mechanical processing). 

Resin curing also impacts the dyeing properties of Superwash wool. As the resin cures it loses its cationic charge and becomes neutral. However if there are some damp patches then in these areas the resin will remain cationic charged and attract the anionic dyestuff (all wool dyestuffs irrespective of type are anionic) more rapidly. In essence if there is uneven curing then it’s more than likely the dyeing will be uneven.

DRYCOM Moisture Sensors on Superwash Sliver at the Dryer Exit

The Streat DRYCOM Moisture Measurement & Control system continuously monitors the moisture content of the sliver and regulates the energy supply to the dryer to maintain the moisture at the desired level.



Water Wizardry

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Streat DRYCOM Moisture Measurement and Control systems provide total solutions for your process.

  • Increased profits
  • Increased productivity
  • Elimination of re-processing
  • Improved downstream processing
  • Improved and consistent product quality
  • Reduced energy consumption
  • Ensures optimum drying level for future processing and ensures adequate resin curing
  • Fewer claims from customers
  • Better deployment of labour to other vital tasks
Translated Document DC-015-01C – Superwash – Chinese