The paper manufacturing industry is one of many that relies heavily on precise liquid measurement and management throughout every production stage.
From the initial stages of wood chip processing to the final coating phases, accurate monitoring of liquid levels and flow rates is vital for preserving product quality, keeping production processes efficient, and preventing costly disruptions or malfunctions.
At Applications Engineering, we are the sole UK and Ireland stockist and supplier of high-quality flow meters and measurement devices, specifically by known brand Kytola. Kytola is a household name in liquid and flow measurement devices, and with that in mind, we felt it prudent to explain how these systems work and how paper mills can choose the right equipment for their specific applications.
The Role and Purpose of Liquid Measurement
Paper mills handle a broad range of liquids at various touchpoints in the manufacturing process. Each of these liquids require measurement and monitoring. For example,
- Papermaking: Level meters are used to monitor pulp levels in headboxes, storage tanks and pulper machinery
- Stock preparation: Stock chests and tanks require level monitoring to check for the presence and prevalence of stock
- Chemical recovery: Level meters are used to monitor liquor levels in tanks
- Coating and bleaching: Coating liquid levels and bleach chemical levels must be measured and monitored
- De-inking: Pulp stock levels need to be checked in flotation cells and tankers
Maintaining precise levels ensures a steady supply of quality materials to the paper machines, not to mention the delivery of best-in-class products.
What Are Bubble Tube Systems?
An effective method for measuring liquid levels in paper processing is the bubble tube system. This is simple, accurate, reliable and cost-effective for measuring liquids in open or vented tanks.
Here are the steps involved:
- A low but constant flow of air or inert gas is purged through a dip tube (with the open end near the bottom of the tank).
- The flow rate needs to be sufficient enough to overcome the hydrostatic pressure created by the liquid.
- A steady stream of bubbles is released from the open end of the tube.
- Provided the flow remains consistent and undisrupted, the liquid level in the tank equates to the pressure inside the dip tube.
- Cost-effective pressure transmitters or differential pressure transmitters are used to check the variations in this pressure to determine accurate liquid level readings.
- For applications where higher consistency is mandated, or when liquids are contaminated (e.g. pulp level measurements in pump standpipes), water purge systems are utilised instead of air.
What is Flow Measurement?
Whilst level measurement ensures proper tank management, flow measurement technologies play an equally vital role in paper mill operations.
For instance:
- Variable area flow meters provide visual indication of flow rates for a wide range of liquids, making them ideal for applications where operators need quick and decisive verification of process conditions.
- Metal tube flow meters offer robust construction suitable for high-pressure applications commonly found in paper mills. These meters can withstand the harsh conditions often present in chemical recovery and pulp processing areas.
- For applications requiring precise volumetric measurement, oval gear flow meters deliver exceptional accuracy, making them particularly useful in coating preparation and chemical dosing applications.
- Seal water flow meters, such as those in the SLM range, serve a specialised function in protecting pumps and mechanical seals from dry running and contamination. In paper mills, where pumps handle everything from clean water to abrasive pulp slurries, maintaining proper seal water flow is essential for equipment longevity and operational reliability.
Choose the Right Device(s) for Specific Applications
Choosing the right measurement solution depends on the specific application(s) and material characteristics.
For example, in digesters, where wood chips are cooked with chemicals at high temperatures, any integrated sensors must be able to withstand conditions like these without compromising on data accuracy and consistency. Water separators, conversely, which remove excess water from pulp before it reaches the paper machine, use guided wave radar technology as they can comfortably avoid issues with foam or buildup which can disrupt processes.
When implementing liquid measurement systems in paper mills, several factors influence performance and reliability. Process conditions such as temperature, pressure, and the presence of foam, vapour, or dust must all be considered. Environmental factors can also impact sensor and measurement device quality and performance, so should be carefully evaluated.
Choose the Right Equipment With Well-Informed Guidance
Understanding the various liquid measurement technologies available and how they apply to specific paper mill processes is essential for making informed decisions regarding the installation and upgrade of your incumbent system. Whether dealing with chemical recovery, stock preparation, papermaking, or coating applications, selecting the right combination of level and flow measurement devices ensures reliable operation and consistent product quality.
Working with a proven Kytola flow meter and transmitter supplier like Applications Engineering will ensure your system will be equipped with the best-in-class products it needs to stay reliable and in good working order all year round.
With many products readily available for pickup from our Sussex warehouse, or available for next-day delivery, look no further Applications Engineering. Contact us today and one of our team will be back in touch with you promptly to discuss your application requirements and recommend you the ideal products you need.
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