Robust design allows consistency measurement in digester applications
October 2018Maintenance, Test & Measurement, Calibration
Harsh process conditions have historically prevented the use of mechanical consistency transmitters in Kamyr continuous digester blow lines. The mechanical design of existing transmitters has not been robust enough to survive the unusually high flow rates enforced with uncooked chips and knots, high chemical concentrations with pH exceeding 13, temperatures above flash point as well as rocks and debris.
Traditionally the operators have made some estimation of the consistency by monitoring the current of the scraper motor, or by measuring the differential pressure at the outlet device at the bottom of the digester. While neither measurement has been adequate for the control of cold blow flow, they were used as an indication.
The KC/3 for severe process conditions
ABB Oy, KPM has developed a new consistency transmitter which finally meets the challenge. This blade type transmitter, called KC/3, is made of a solid titanium body without any seals, O-rings or gaskets. This leak-proof design can safely be installed in very severe process conditions, including blow lines and blow tank outlets.
Stora Enso in Oulu, Finland installed a KC/3 in its pulp mill blow line. The installation was straightforward as all required hardware was included in delivery. The special protective deflectors designed for blow line applications with detailed installation and welding instructions are part of the delivery.
The benefits
Occasionally the production rate can drop due to disturbances in flow internal to the digester e.g. chip column movement can stop because of channelling in the washing zone. This will immediately cause serious quality problems. Chips are over cooked, strength properties suffer, and, of course, production rate drops as a result of lower blow consistency.
Having a reliable consistency measurement in the blow line, the operator is warned immediately about a disturbance and can react swiftly. He could, for example, temporarily reduce the flow in washing circulation or change the locations of the wash liquid feed.
During normal run, the differential pressure at the bottom, scraper current and consistency track each other fairly well. The pressure difference does not see the consistency drop but on the contrary indicates higher numbers. Shortly thereafter, the scraper current of the diffusion washer proves that consistency really has dropped. In addition to prompt and reliable information of process disturbances, the production rate calculation becomes more accurate.
This helps to track and control the grade changes to the screening and washing stages. Reliable and exceptionally strong the KC/3 when installed in a blow line provides an important measurement to assist the operators with digester control.
Electrostatic spark discharge – when static strikes back Wearcheck
Maintenance, Test & Measurement, Calibration
WearCheck technical manager, Steven Lumley explains how static electricity accumulates in modern low-conductivity lubricants, why compact system designs and fine filtration make ESD more likely, and how to recognise the degradation it leaves behind.
Read more...High-speed cameras for crash testing Horne Technologies
Maintenance, Test & Measurement, Calibration
Vision Research has expanded its Phantom C-series with two cameras optimised for crash and safety testing, offering 4 and 8 megapixel sensors rated to 170G, up to 1180 frames per second, and Phantom Academy application training planned for South Africa next year.
Read more...SKF extends remanufacturing expertise to bearing clearance modification SKF South Africa
Maintenance, Test & Measurement, Calibration
Using its clearance modification expertise, SKF helped a mining equipment OEM salvage spherical roller bearing inventory that would otherwise have been scrapped, confirming a new capability within its remanufacturing services and avoiding redundant procurement.
Read more...When maintenance-system compliance starts replacing plant reliability Wearcheck
Maintenance, Test & Measurement, Calibration
WearCheck ARC division manager, Annemie Willer argues that the greatest threat to effective maintenance is no longer a lack of technology, but the gradual replacement of technical judgement by CMMS compliance, leaving no one owning the machine.
Read more...Nitration: the acid you didn’t see coming Wearcheck
Maintenance, Test & Measurement, Calibration
Nitration is as destructive as oxidation in many engines but far less understood. WearCheck technical manager, Steven Lumley explains how nitrogen oxide gases degrade lubricants, why the process is difficult to detect, and what oil analysis can reveal before damage occurs.
Read more...KSB makes mechanical seals for its own pumps and other brands
Maintenance, Test & Measurement, Calibration
KSB Pumps and Valves is expanding its range of mechanical seals to fit its own pumps and competitor brands. The portfolio covers component and cartridge seals, API 682-compliant systems, slurry and high-pressure seals, and ATEX-certified solutions, supported by refurbishment and field service capabilities.
Read more...Omniflex delivers ICCP systems in London Omniflex Remote Monitoring Specialists
Maintenance, Test & Measurement, Calibration
Omniflex has supplied impressed current cathodic protection systems for landmark London buildings, protecting reinforced concrete from corrosion and extending the service life of commercial, retail and heritage sites.
Read more...Modernising acid cooler protection without disrupting production Omniflex Remote Monitoring Specialists
Maintenance, Test & Measurement, Calibration
Omniflex has supplied an advanced anodic protection control system to phosphate producer Foskor, replacing a legacy transformer rectifier system while maintaining uninterrupted production. The distributed PowerView CP solution provides remote monitoring and DCS integration.
Read more...Engineering partnership delivers longer life for vibrating feeders in mining
Maintenance, Test & Measurement, Calibration
OST-Africa’s combination of VISAM vibrating motors and advanced rubber mounting technology has helped Euro Sales achieve a 30 to 40% increase in component life on vibrating feeders at several major mining operations, with zero mount failures in the first 12 months.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version