Is it water or orange juice?

11/12/2010


Dear Control Engineering: I am working in the process to automate a pasteurizer. I am looking for a sensor technology to detect the change from water to orange juice, and from orange juice to water in the output process. It has a color sensor, but it doesn't detect the change all that well. Do you know a better sensor? Thank you. –Erick

When looking at a question like this, we have to think about how water is different from orange juice, and then which of those differences is the easiest to detect or quantify. Apparently color, the most obvious choice, isn’t good enough, so what are some of the other possibilities? Orange juice is more acidic and has more sugar in it, so those might be more practical to detect. I asked Jim Gray, application manager at Rosemount Analytical Instruments for some suggestions. He says, “I think conductivity using a toroidal sensor would be the way to go. That would be the easiest from a maintenance standpoint. The conductivity of OJ should be greater than the conductivity of water, although I don’t have any number handy. The problem with pH would likely be the sensor drying out when the process is down. A Coriolis flowmeter would provide a continuous inferential measurement of concentration but is much more expensive. Conductivity should be sufficient for a status indication.”

A toroidal conductivity sensor.A toroidal conductivity sensor is a doughnut-shaped probe that inserts into the process liquid stream. The toroid itself has two coils. One is powered and creates a magnetic field. The second is a receiver. The current induced in the receiver is in proportion to the conductivity of the surrounding liquid. The probe can be encased in an appropriate grade of plastic to withstand the process liquid. Units are available that are designed for sanitary applications in food processing.

--Peter Welander, pwelander@cfemedia.com



The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
Pipe fabrication and IIoT; 2017 Product of the Year finalists
The future of electrical safety; Four keys to RPM success; Picking the right weld fume option
A new approach to the Skills Gap; Community colleges may hold the key for manufacturing; 2017 Engineering Leaders Under 40
Control room technology innovation; Practical approaches to corrosion protection; Pipeline regulator revises quality programs
The cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Power system design for high-performance buildings; mitigating arc flash hazards
VFDs improving motion control applications; Powering automation and IIoT wirelessly; Connecting the dots
Natural gas engines; New applications for fuel cells; Large engines become more efficient; Extending boiler life

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
This digital report explains how plant engineers and subject matter experts (SME) need support for time series data and its many challenges.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.
Maintenance Manager; California Oils Corp.
Associate, Electrical Engineering; Wood Harbinger
Control Systems Engineer; Robert Bosch Corp.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me