Category Archives: Process

What is Dew Point Temperature

Our state side colleagues have put together a great FAQ technical note explaining dew point temperature in more detail!

chilled mirror / dew point mirror
chilled mirror / dew point mirror

The FAQ technical note can be accessed here and answers the following key questions!

  1. What is dew point temperature?
  2. What is frost  point?
  3. When should I choose dew point as the parameter I measure?
  4. What are the pros and cons of measuring dew point versus relative humidity?
  5. Does dew point change as the ambient temperature changes?
  6. How does pressure affect dew point measurement?
  7. What are the common technologies for measuring dew point?
  8. Isn’t dew point temperature the same thing as wet bulb temperature?
  9. How do I know which technology is best for my application?
  10. Where can I buy a dew point instrument?

Rotronic produce precision low dew point sensors for low moisture applications in addition Rotronic UK is the UK distributor for world class MBW chilled mirrors, please contact us for additional information!

Dr Jeremy Wingate
Rotronic UK

Temperature, Humidity and Ceramic drying

Introduction

Ceramic drying is one of the most important processes in ceramic production technology. Quality defects of ceramic products are caused by improper drying. The drying affects the quality of the finished product, the throughput but also the overall energy consumption for ceramic manufacturing enterprises. According to various statistics, generally energy consumption during drying processes represents 15% of total industrial fuel consumption. However within the ceramic industry, the energy consumption used for drying accounts for a much higher percentage of the total fuel consumption. Therefore energy saving within the drying process is extremely important for all enterprises. Drying speed, reducing energy use , ensuring high quality products and reducing  pollution are all  basic requirements for any ceramic manufacturer today.

Measurement and Control in Ceramic Dying

Ceramic production is done through several main processes: casting, drying, glazing, firing…

The casting and drying are important processes for ceramic. A forming workshop is equipped with an intelligent control system. The control system regulates the relative humidity value using information provided via room and process sensors. Sensors have to measure accurately ad repeat ably despite the challenging and often dusty conditions. Humidification and dehumidification processes require substantial energy so tighter control is a huge energy saver for these industries.

A constant temperature is also achieved via the intelligent control system. With a stable temperature and stable relative humidity within the workshop, manufacturers ensure the quality of  the ceramic body drying.

After stripping the body from the cast, the body contains a very high relative humidity level. During the drying process, the body may crack or deform due to the speed in which the product is dried (volume and shrinkage) which ruins the product and decreases the throughput.

Exactly this part of the process has become a major bottleneck within the production process of ceramic products.

In a casting workshop, stable environments can reduce the cracking and deformation effectively. It also improves the throughput rate of semi-finished products and shortens the drying period, also prolonging the life frame of the  plaster cast.

So constant temperature and  relative humidity according to the set values will help all factories to improve the throughput, reach an optimal drying speed and deliver the best quality results available.

How can we help?

Rotronic provides a range of instruments for environmental monitoring and control.

Rotronic HC2-IC industrial temperature and humidity probes, are successfully working in these tough applications, the probes are installed on the roofs of drying chambers and resist chemical pollution. With a flexible  HF5  transmitter, the outputs can be set to the customers requirements.

With both digital and a range of analogue outputs available as well as several probe mounting options, products can be selected for all applications.

Measurement data can be viewed on HF5 with display or remotely via HW4 software. Ease of calibration and sensor replacement ensures down time is kept to an absolute minimum.

Dr Jeremy Wingate
Rotronic UK

 

Energy Efficiency and Reliability in Modern Data Centres

Introduction

Data centres are rapidly becoming the power houses of the modern world. Combined with the rise of digital industries, virtually all business operations now rely in some way on the transfer of data. As data transfer rates increase in tandem with an explosion in mobile communication the demands on data centre infra-structure are ever increasing.

It is estimated that by 2018 global data traffic will exceed 8500 exabytes (32% compound annual growth rate).

Data centres provide the infra-structure to support the transfer and hosting of data. They are often classified into 4 tiers. Tier 4 provides highest levels of redundancy, security and efficiency. For example, a Tier 4 data centre is required to have an uptime of 99.995% equivalent to less than 27 minutes downtime per year! Tier 4 sites have fully redundant systems, power supplies and biometric security. Zero downtime is the ideal as the costs incurred via end user penalties can be huge.

data centre tiers

Why the need to measure temperature, humidity and differential pressure?

Data centres must be maintained to specific environmental conditions to ensure the performance and longevity of the hardware installed. As standard, temperature must be 18-27 °C, dew point 5-15 °C dp and humidity no higher than 60 %rh. This ensures the hardware is at a suitable temperature, condensation is avoided and the chance of static build up is reduced (caused by low humidity).

A control range of ±9 °C may seem relatively broad, however 100% of the energy supplied to server hardware is converted to heat. In most data centres if the cooling system fails and servers are not shut down, heat levels will rise above a critical 35 °C within minutes or even seconds. If unchecked, temperature levels will rise causing hardware damage and can result in electrical fires.

Achieving the specified control range requires precision sensors and advanced control systems. Typically modern data centres are designed using computational fluid dynamics to ensure the very highest efficiency. Despite this it is estimated around 5% of US electrical energy used is for data centre cooling.

pue power usage effectiveness

Since 100% of electricity utilised by servers is converted to heat, theoretically a 100% efficient cooling system would require an equal amount of energy. Efficiency is measured by comparing total facility energy use, with IT equipment energy use. This is called Power Usage Effectiveness (PUE). Theoretically PUE can be 1 but typically reported values are above 2. By utilising precision measurements and design, modern data centres achieve PUEs of ~1.1!

An improvement of 0.5 in a data centre’s PUE  equates to a energy saving of ~£2.2 M & ~12,000 tonnes CO2 over 5 years (for a site with 1 MW load).

 

What solutions can Rotronic offer?

Rotronic provides a range of instruments for environmental monitoring and control. Reliable and precise outside air sensors and weather shields enable natural cooling to be utilised where possible.

Inside the data centres, Rotronic interchangeable HC2-S probes can provide a combination of precise, fast response temperature and humidity measurements with ease of calibration. Our latest PF4 differential pressure transmitters provide precision low drift measurements.

With both digital and a range of analogue outputs available as well as several probe mounting options, products can be selected for all applications.

Importantly though we aim to understand your needs and build a relationship with the goal of providing an appropriate solution, combining instruments, training, calibration and ongoing support.

Dr Jeremy WIngate
Rotronic UK

 

Sugar Production and Relative Humidity

The sugar market worldwide

Sugar is one of the most important raw materials traded on the worldwide markets.

Top 5 sugar producing companies

1. Suedzucker AG,

2. Cosan SA Industria & Comercio

3. British Sugar PLC

4. Tereos Internacional SA

5. Mitr Phol Sugar Corp.

In the 18th century only a few countries were producing sugar. However, these days over 100 nations process different base materials into sucrose. Remarkably India, China, Brazil & the European Union alone deliver 50% of the global demand.

Sugar Facts:

– Worldwide 170 million tons of raw sugar were produced in 2011/2012

– Brazil, India, China & EU are the most important sugar producing nations

– With an annual consumption of more than 24 million tons India, is the world’s largest market for raw sugar

Raw materials & processing

In temperate regions such as West, Central & Eastern Europe, the United States, China and Japan raw sugar is produced from sugar beet. However in the tropics and subtropics sugar is extracted from sugar cane.

800px-cut_sugarcane

Sugar cane & Sugar Beet

Processing

The processing of these two raw materials only differs in the first few steps. The main goal is to extract the juice, containing the sugar,  as efficiently as possible.

Extracting the sugar

Sugar cane is cut into small pieces during the harvest. It is then put through an industrial press to squeeze out the sweet sap.
Sugar beet has to be processed in extraction towers, where the plants release their sugar during a hot water treatment at 70°C.

Evaporation

After filtering the juice the water is extracted by passing through different stages of evaporators until only a thick syrup is left consisting of around 70% sugar.

Crystallisation

The syrup is then boiled until sugar crystals are formed. These crystals are then cleaned through centrifugation. To further improve purity this process is repeated twice.

Cooling & drying

Now the sugar has to be dried. One option is in large scale drum dryers at a temperature of 60°C. after drying, the sugar is cooled down on fluidized-bed coolers before heading to the warehouse or packed for shipping.

Trommel2_400_219_01

Inside a drum dryer.

Storage & logistics

Sugar belongs to the group of hygroscopic goods with an extremely low water content – below 1.5%. Basically sugar is a robust material but vulnerable to high humidity and temperature changes.
Generally it is recommended to store and transport sugar at a temperature of 20-25°C and 25-60% relative humidity.

By taking a closer look at the adsorption curve of sugar it is easy to see that over a long range of relative humidity the product quality is not affected. But as soon as the humidity level rises to 75% sugar starts to clump and above 80% relative humidity even dissolves .

Storage

Immediately after production the refined sugar is stored in humidity controlled sugar terminals or ventilated silos connected to dehumidifiers.

6.2.4. Sugar Terminal 5086

Sugar in a storage terminal

Logistics

Large quantities are trans-ported in silo trucks or train wagons. When sent by ship sugar is packed in double-walled bags made of natural fibre and plastic. If sealed like this, temperature is the crucial parameter which can affect the quality of the sugar. Due to big differences in temperature water vapour left inside the bags may cause clumping and even liquefaction.
The finer the sugar, the higher the risk of clumping.

Caking-dark-brown-sugar

Sugar clumping

Why the need to measure humidity?

As seen above, temperature and humidity measurements are crucial parameters in the sugar industry. Due to its hygroscopic behavior sugar can resist small changes in humidity, and slight temperature variations are not a major problem. But as soon as relative humidity rises above 80% or temperature changes significantly, the product can be destroyed as it clumps or even turns liquid.
During the process of evaporation, crystallisation, drying and cooling temperature and humidity play a huge role.

Philip Robinson                                                                                                        Rotronic UK

 

Humidity measurement in Paint Spray Booths

Paint booths in general

Spray painting has existed since the late 1800’s. The technique was developed in a bid to accelerate painting times compared to brush painting. Spray painting is a method of painting where paint is atomised onto a surface via a spray gun. The paint is mixed together with a solvent or water (called a carrier) so that it can be applied correctly.

Cars, aircraft, boats and other such equipment is often spray painted in a spray paint booth.

A spray booth is an enclosed room, designed for spray painting. Depending on the requirements, the booth may be equipped with filtered air to avoid getting dust in the room and an exhaust air system to clear the fumes of any evaporating solvents used during the spray painting process.

Regulations, such as the Occupational Safety & Health Administration from the United States department of Labor have a criteria for design and construction of spray booths state that a spray booth is: a power-ventilated structure provided to enclose or accommodate a spraying operation to confine and limit the escape of spray, vapour and residue, and to safely conduct or direct them to an exhaust system.

Spray paint booths regulate relative humidity, temperature, airflow and pressure to ensure a quality coating and a perfect curing.

Certain paints contain flammable solvents which release flammable fumes: in this case explosion-proof components are required for all measuring equipment that come in contact with the fumes.

Paint dry and cure times
Paint dry and cure times

Why do we need to monitor and measure in Paint Spray Booths

In order for paint to dry correctly within the paint booths, the relative humidity and temperature levels should be within the following conditions:

 – 65 to 75%rh
 – 20 to 24°C

Based upon the intake air, there may be a requirement to either dry or humidify the air in order to reach the desired values. From the temperature side, exactly the same thing: the air might need to be cooled or heated depending on the outside temperature.

Additionally, paint booths might have a  separate monitoring system inside the booths in which the different elements are painted. In order to ensure that the paint is  applied correctly to the element to be painted, it is important to ensure that the surface temperature of the element is not too close to the dew point level in the booth.

If the surface temperature of the element to be painted is close to the dew point temperature, then there will be risks of condensation forming on the surface of the element. If this were to happen, the coating will not be optimal and the drying and curing phase will not be completed properly and the results could be catastrophic.

 

Rotronic have recently launched a totally new range ATEX (Intrinsically Safe and Explosion Proof) instruments. Paint spray booths typically require ATEX certified instruments.

More details here.

Rotronic ATEX range
Rotronic ATEX range

 

A look at the Beer Brewing Process – Just in time for the Rotronic 2014 International Sales Meeting

Beer brewing in general

There is no exact date, as to when the first beer was brewed but already at the beginning of the fifth millennium BC, people in southern Mesopotamia, in a region known as Sumer (modern Iraq), were brewing beer.

Beer, like other commodities such as wheat and other grains, was used as a currency. A clay tablet, dating from 6’000 BC contains one of the oldest known beer recipes.

Beer Map
Beer consumption throughout the world

The basic ingredients of beer are: water; a starch source: which is able to be fermented; yeast: to produce the fermentation; a flavouring such as hops. Yeast is the microorganism that is responsible for fermentation. Specifically Saccharomyces cerevisiae is the species of yeast that is used for brewing.

Facts & figures:
Beer is the third most popular beverage in the world, coming in directly behind tea and water.
American beer is made mostly from rice. This was invented to give American beer a lighter taste and tap into the market of women buyers.
In the UK 28 million pints of beer are consumed every day, which equates to 100 litres per head each year.
Belgium has over 400 different beer brands.
Cenosillicaphobia is the fear of an empty glass.

There are several steps in the brewing process, which include malting, milling, mashing, lautering, boiling, whirl-pooling, fermenting, conditioning, and filtering.

Step by step brewing:
  • Malting: germination of cereal grains. The sprouted cereal is then kiln dried at around 55°C. Milling: grinding of the malted cereal.
  • Mashing: the cereals are mixed with water and then heated.
  • Lautering: separation of the mash: the liquid (wort) is separated
    from the residual grains.
  • Boiling: the wort is boiled to ensure sterility and then hops are added for flavour!
  • Whirl-pooling: the wort is sent into a whirlpool, removing the dense particles using centrifugal force.
  • Fermenting: yeast is added to the wort: conversion of the carbohydrates to alcohols and carbon dioxide – the chemical conversion of sugars into ethanol!
  • Conditioning: the tank is cooled and the yeast and proteins separate from the beer. This conditioning period is also a maturing period.
  • Filtering: the beer is filtered: stabilising the flavour.
  • Packaging: the beer is packed then to the customers
Example brewing process
Example brewing process
Why the need to measure the carbon dioxide?

Carbon dioxide Carbon dioxide (CO2) is a naturally occurring chemical compound. It is a gas at standard temperature and pressure.

We inhale oxygen and exhale carbon dioxide. The carbon dioxide level in exhaled air is rather constant: around 3,8%. When carbon dioxide is exhaled it will quickly be mixed with the surrounding air even indoors and provided that the ventilation is good, the concentration will be reduced to harmless levels. Indoor carbon dioxide levels usually vary between 400 and 1’200 ppm (parts per million). Outdoor carbon dioxide levels are usually 350 – 450 ppm.

Beer brewing process: Heavily industrialised or contaminated areas may periodically have a higher concentration of CO2. Carbon dioxide is released during the beer brewing process and as you will see below, CO2 is toxic for living organisms. In brewery environments where process generated carbon dioxide is widely present, the maximum permitted carbon dioxide concentration according to most standards is as high as 5’000 ppm (5%) during an 8 hour working period.

Beer storage: Most beer leaves the brewery carbonated: beer and carbon dioxide are sealed in a container under pressure. It can be carbonated during fermentation but it can also be carbonated in the bottle. In this case the beer is allowed to ferment completely. It is left unfiltered which leaves active yeast suspended in it. A small amount of sugar is then added at bottling time. The yeast begins to act on the sugar: CO2 is released and absorbed by the beer.

Beer can also be force carbonated, in which case it is allowed to fully ferment. Then CO2 is pumped into a sealed container with the beer and absorbed by the liquid. In this case, a tank of carbon dioxide will also be required. Undetected leaks in a gas system is a costly waste and a safety risk to personnel. While small leaks are inherent in any gas system, those of significant size raise the level of economic and safety risk.

How does CO2 affect the human body?

Due to the health risks associated with carbon dioxide exposure, there are regulations and laws in place to avoid exposure! The US National Institute for Occupational Safety and Health (NIOSH) states that carbon dioxide concentrations exceeding 4% are immediately dangerous to life and health.

In indoor spaces occupied by people: concentrations higher than 1’000 ppm will cause  discomfort in more than 20% of occupants. At 2’000 ppm, the majority of occupants will feel a significant degree of discomfort and many will develop nausea and headaches.

How CO2 affects the body
How CO2 affects the body

Case study: The lake Nyos
The lake Nyos is a crater lake situated in Cameroon. In 1986, a pocket of magma from under the lake, leaked a large amount of CO2 into the air. The result was suffocation of around 1’700 people and 3’500 livestock!

As we take beer brewing seriously we will be sure to test a number of varieties with our colleagues from the world over at the Rotronic 2014 International Sales meeting in Grindelwald next week!

Dr Jeremy Wingate
Rotronic UK

“Humidity & Temperature Sensors Help Cheese Taste Just Right” GUEST BLOG POST by THORNE & DERRICK

Thorne and Derrick have written a great blog post on the importance of quality measurement and control in cheese manufacturing (a key industry for Rotronic sensors due to their reliance to the high humidity conditions in cheese maturing!) 

Check out the post here…

Humidity & Temperature Sensors

Thorne and Derrick are national distributors and worldwide exporters of process & mechanical equipment. 

 

Would you like us to share your blog posts on measurement or humidity? Please contact us!

Dr Jeremy Wingate
Rotronic UK
jeremyw@rotronic.co.uk

 

The Great British Bake Off… It’s all about humidity!

Bread – The stuff of life!

Most of us have a never ending choice of the most delicious breads, cakes and pastries to please both the palate and the eyes. We have become so used to this diverse range of bread and baked products, but do you how bread originally came into existence?

The interesting history of  what is now called the “staff of life”, bread, and the making of it, started in comparatively recent times.

At the very beginning of recorded history there was the discovery of fire making and thus along with light, heat could be generated. Then it was found that different grasses and their seeds could be prepared for nourishment.

Later, with the combination of grain, water and heat, it was possible to prepare a kind of dense broth. Hot stones were covered with this broth or the broth was roasted on embers and “hey presto” the first unsoured flat bread was created. This ability to prepare stable food radically changed the eating habits and lifestyles of our early ancestors. They progressed from being hunters to settlers.

Facts & figures:

  • Records show that as early as 2600-2100 B.C. bread was baked by Egyptians, who it is believed had learned the skill from the Babylonians.
  • On average, every American consumes around 53 lb (24 kg) of bread per year.
  • The “pocket” in pita bread is made by steam. The steam puffs up the dough and, as the bread cools and flattens, a pocket is left in the middle.
  •  US Farmers receive just 5 cents (or less) for each loaf of bread sold.

Why the need to measure humidity?

The production of baked goods such as bread, cakes, biscuits and pastries requires a number of processing steps in which humidity and temperature play an important role.

After mixing, it is typical to divide the dough into pieces and allow it to rest for a few minutes so that the gluten network in the dough can relax allowing easier moulding, which is the next step.

If at that stage, the temperature is too hot the dough will be too sticky and cannot be easily processed further, if too cold the dough can become damaged during moulding which leads to holes forming in the bread. If the humidity level prior to the moulding process was too low a skin of dry dough can form on the dough surface. This makes it harder for the dough to increase its volume during the next
process step called proving.

Proving is the professional term for the final dough-rise step before baking, where 90% of the bread volume is achieved. To achieve consistently good dough rising results special chambers are used. These chambers can maintain the ideal environment for the yeast to grow. Depending on the yeast and flour used, temperatures between 38…42°C and humidity levels between 70…80%rh are considered ideal.

In summary, the use of quality ingredients and careful handling throughout the various stages of production will not result in a quality product  unless the dough temperature, and the temperature and humidity of the bakery are carefully regulated. Modern day bakeries use custom ventilation systems that are controlled by precision humidity and temperature sensors.

So once again the behavior of the humble water molecule is to blame! In this case for the stricken faces of The Great British Bake Off contestants as they stress about the quality of their crust and whether the dough will be cooked through to perfection!