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Have questions about Moisture Control and Analysis?

Visit the Powder Bulk Solids website and ask PSC’s Chris Pike.

Online % Solids Analysis Sludge Cake-Sewerage Treatment

Biosolids are an unavoidable bi-product of sewerage treatment.? However, through careful treatment, Biosolids can be recycled and used effectively as fertilizer and compost as as for combustion processes.? Water must be removed from sludge in order to minimize transportation costs as well as to render it suitable for agricultural or combustion purposes.? This form of sludge is described as sludge “cake.”

Sludge Treatment Processes

The sludge undergoes digestion, a heating process which destroys the bulk of present pathogens prior to passing through large dryers and a pelletizer.? Alternatively, the sludge is “lime stabilized.”? The addition of CaO (lime) to sludge results in a exothermic chemical reaction which eliminates pathogens.

Gauge Location and Installation

Gauge location is dependent on the Treatment Process, however, installation above a belt conveyor, if possible, is simple and effective.? In order to improve measurement performance, the installation of a doctor blade prior to the gauge location, helps to break up and spread the cake solids over the belt, thereby presenting a fresh surface of product to the gauge.? Implementation of two doctor blades (one perpendicular to belt direction and another obluque to the blet) to channel product onto a transfer conveyor will provide the best results.

The % solids readout can be used to control the centrifuge, press and dryer operation as well as the rate of lime addition where applicable.

Measurement Performance

Measurement accuracy is dependent on the composition of the sludge and how variable it is over time, also on the % solids level.? In most instances, however, the % solids reading is accurate to within +/- 0.5%.

Customer Support and Service

Process Sensors Corporation is dedicated to providing the most reliable, dependable and accurate Instrumentation in the world, but more importantly the best Customer Support.? We provide Start-up & Calibration Services, In-Plant Evaluation & Service and Repair at our Service Centers in Asia, Eastern Europe, Western Europe and North America.? The goal of these Services is to ensure our analyzers are maintained and utilized to their fullest capability.

For those Customers who wish to have their instrumentation repaired, please call for a service price quote.? ? The Instrumentation will be repaired, tested and if desired re-calibrated.? ? In most cases Instrumentation can be returned with 48 Hours upon receipt of the Instrument.

Moisture In Hydrated Lime, Ca(OH)2

Moisture measurement is made to ensure that moisture levels do not exceed the 3% maximum.? If this level is exceeded the product will clump, be difficult to load and transport and cause blockages within the slaker.

Production of hydrated lime

Hydrated lime is obtained from hydrating calcium oxide or quick lime.? The hydration process is referred to as “slanking,” the water and calcium oxide undergo a controlled exothermic reaction resulting in “dry” free-flowing calcium hydroxide (hydrated lime powder).? ? Both temperature measurement within the reactor and moisture content are used to control the water addition to ensure moisture content is optimized but doesn’t exceed the 3% limit

Gauge location and Installation

The gauge is positioned at the exit of the slaker, 6-15″ above the hydrated lime.? Product flow should be continuous and of sufficient depth that the transporting medium isn’t seen by the gauge.? If flow is discontinuous a gating option can be used to enable measurement only when product is viewed.

Measurement Performance

Measurement? ? ? ? ? ? ? ? ? ? ? ? ? ? Location? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Target Moisture ? ? Typical Accuracy

Hydrated Lime? ? ? ? ? ? Exit of the reactor? ? ? ? ? ? ? ? ? ? ? 0-3%? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0.2%

Asphalt Paving Dryers and Mixers

Asphalt dryer with IR thermometer mounted on exit chute

The Application

Asphalt used for road surfacing, parking lots etc., is manufactured in a two-stage process where crushed stone and sometimes crushed, recycled glass is mixed with tar and other binders.

First, the crushed material is dried and preheated in a continuous, rotary, horizontal furnace. It is then conveyed to a mixer where the binders are added and the mix is further heated. The source of heat in both cases is a single, gas or oil fired burner. When the temperature is correct, the mix is
dumped into a truck and taken to the laying sight.

Thermocouples are used to measure and control the temperature in the dryer and mixer, but are relative insensitive to rapid temperature changes and require frequent replacement. IR Thermometers are more responsive to process temperature changes, and do not need to be in contact with the abrasive material.

Asphalt Recycling Plants

Asphalt recycling plants are increasingly being used. Such plants operate on the highway, scrape up the existing road surface, crush it and pass it through a rotary heater where new binders are mixed in. The reconstituted material is then re-laid, all in one continuous operation.

The Importance of Temperature Control

The temperature at which the asphalt is laid down is critical to the life of the road surface, too low a temperature results in premature disintegration. If the temperature is too high, the material will sag and spread. This is particularly critical with high-speed, automatic laying machines.
Large highway construction and resurfacing contracts are carried out under the supervision of a representative from the highway authority, who monitors the laying temperature and the load in the trucks when they arrive, using a handheld IR thermometer.? If the temperature of the load is too
low, it is rejected and turned back to the supplier.

Application Tips

Plant operating conditions are extremely dusty. A good, well-maintained, filtered air purge is therefore essential, and periodic, manual lens cleaning may also be necessary. If compressed air cannot be made available, combustion air is an alternative, though less desirable.

In addition to connecting the purge air to the IR thermometer air purge unit, it should also be connected at points down the sight tube as shown in the picture below.

The length of the sight tube and angle should be such that ricocheting, crushed material cannot reach the IR thermometer lens. The thermometer should be shielded from direct sunlight, snow or rain. In some cases the
pyrometer is removed and stored during the off season.


IR Thermometer with air purge on exit chute of dryer

The Market

There are many, large asphalt paving contractors in the USA, and perhaps thousands of smaller ones with just one or two machines. Many of the smaller plants operate only spasmodically, as business dictates.

There are also a limited number of OEM?s worldwide.

The most efficient way to penetrate the market therefore is to focus on the corporate or regional engineering staffs of the larger contractors, and on the OEM?s. They have the authority to specify and mandate equipment purchase.? This is not to say that individual plants should be ignored, but
multiple sales are less likely from such sources.

Instrument Selection

Process Sensors Model PSC-SS-Laser with a 75:1 FOV a spot size of 0.63? at a 48? distance is used for continuous measurement at the mixer and dryer areas. Outputs: 4 -20mA, T/C and Ethernet

Process Sensors portable Models PSC-MS and PSC-PSLT can be used for spot measurements.

New Process Sensors PTI-170L Thermal Imaging Camera Features 44% Better Resolution Than Ordinary 320 x 240 Cameras


Process Sensors Corporation has broken new ground with the introduction of its brand new Model PTI-170L High Resolution Thermal Imaging Camera with Dual Vision, designed for use by maintenance professionals, service and electrical inspection thermographers, building inspectors, and energy conservation specialists.

The high resolution Model PTI-170L is equipped with a 384 x 288 pixel UFPA detector that delivers 44% more pixels and is visibly sharper than the arrays of the industry-standard portable imaging cameras used today. The versatile camera produces sharp, crisp images that are exceptionally clear, offers a fast frame rate of 60HZ and utilizes easy-to-use comprehensive report generating software that turns out detailed reports in an instant.

The fully radiometric Process Sensors PTI-170L stands out as an exceptional performer in the power / electrical industry, for energy audits, building inspections, roof inspection, and HVAC applications that have recently become more critical as both industrial and private individuals struggle to conserve and maximize precious energy sources efficiently. ? It is ideal for use in weatherization and home energy improvement programs.

Enhanced features of the camera provide dual vision capabilities that blend (picture-in-picture) high resolution thermal and visible light images together on one screen to simplify analysis and improve problem detection.? A selection of six different color palettes allows user to easily detect temperature anomalies for the intended application.? The light weight, yet rugged, PTI-170L sports manually focusable optics adjustable from 300mm to Infinity and an onboard full color CCD camera. ? Video output is PAL and NTSC.? A distance adjustable position laser pointer is standard, as well as a high resolution 2.5? LCD, color VGA digital backlit display.

The PTI-170L?s short cut keys enable an operator to bypass the main menu with the push of only one button and provide quick access to the all-important temperature level, sensitivity and save features instantly.

The Process Sensors PTI-170L series of imaging cameras offer extended temperature ranges from -20?C to + 1500?C (-4?F to +2732?F) and includes a 2G removable SD card for high capacity memory storage capabilities ? up to 3000 IR images.? Optional Bluetooth voice annotation is also available.

Reasonably priced, the Process Sensors Model PTI-170L Series delivers the very best price performance ratio in its class while delivering unprecedented high resolution imagery to meet the demanding needs of industry professionals.

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5th Annual Total Quality Management Short Course

September 14-18

Ohio State University

Columbus, OH

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September 21-23

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Concord, NC

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Moisture In Pharmaceutical Powders

It is important that moisture levels are accurately maintained throughout the wet granulation or drying process within the fluid dryer.? This ensures consistent product formation in the tableting and pelletizing processes, which follow and ensure the effectiveness of the drug.? Continual monitoring and control of moisture will increase productivity and maximize the efficiency of the operation.

Pharmaceutical Manufacturing Processes

Granulation Process: A water based solution is slowly sprayed onto the excipients to ensure even distribution.? Air is simultaneously pumped through the bed of powder to gently lift and mix the ingredients.

Drying Process: This commences after the aqueous solution has been added (when preceded by a granulation operation).? When the batch reaches the desired moisture content, the air shuts off and the bowl of powder is transferred to the next operation.

Measurement and Location

Traditionally, moisture content is approximated by measuring the temperature of the exiting air.? This can prove unreliable as it is dependent upon the relative humidity and temperature of the incoming air.? To further confirm that the moisture has reached the required level, a sample is removed for laboratory testing.

Using the MCT 360? NIR on-lin moisture analyzer, moisture can be measured instantaneously “in situ” by using either a sappire viewing window, or a probe with an air purge to ensure non-adherence of product to the window.? Alternatively, if there are multiple flid bed dryers, an MCT600 laboratory instrument can be set up on a cart and transported to each Dryer in order to obtain instantaneous readings on samples extracted from the bowl.



Twin lasers and a built-in optical telescope simplify precise aiming on small targets at extended distances with Process Sensor Corp.?s latest addition to their range of portable infrared thermometers.? The Models PSC PTLST-20-1M and 2M also feature a dual grip handle to assist steady aiming.

Typical applications for the portable instrument are slag free molten metals and crucibles, furnace surveys in the steel, glass and refractory industries, molten glass, semiconductor wafers, composites, ceramics, induction heating of metals and spot measurements in vacuum furnaces.

Two models offer temperature ranges of 650 to 1800?C on the 1M version, or 385 to 1600?C on the 2M.? Spectral responses of 1.0?m and 1.6?m respectively, enhance measurement accuracy when monitoring relatively low or variable emissivity targets.? The two lasers are mounted such that the beams converge at the target distance, illuminating the measured area.? A Ni-MH rechargeable battery provides a generous 25 hours of operation without the lasers, and 5 hours with the lasers and display back-lighting on.

Other outstanding features include an internal 2000 reading data logger, and max/min audible, and visual three color alarm signaling on the integral display.? A USB interface and included PSC Connect software are provided for downloading data to a computer for storage and analysis.

For more information, please visit our website at



Digital electronics and precision engineering contribute to the small size of the latest addition to Process Sensor Corps.? IR thermometer line.

The DS-40N or DG-40N series of stainless steel pyrometers are 124.5mm long overall by M40x1.5 threaded diameter, operates in a loop powered mode to produce a linear 4 to 20mA output, over selected temperature ranges from an overall span of 250 to 2500?C in two models.? In a 4 wire mode, the sensor also offers green LED, illuminating the exact target size, or laser aiming.

Depending on the model, either DS-40N or DG-40N, and temperature range, selected optics provide small target, close focus e.g. 1.2mm diameter at 210mm distance, or extended focus out to 4m with a 20mm diameter target.? A USB connection gives access to PC adjustments of such parameters as emissivity, response time, temperature sub-range and peak picker, with supplied software.

Without cooling, the non-contact temperature sensor will operate in ambient temperatures up to 70?C, and in higher ambient of 200?C with the optional cooling and lens-purging jacket.? The Model DS-40N has a spectral response of 0.8 to 1.1?m, and the DG-40N 1.5?m to 1.8?m, for minimum vulnerability to variable target emissivity, and to optimize the effective emissivity of low radiance targets.

The temperature ranges, optics, rugged construction and signal processing capability will appeal to users in the Steel, Ceramics and Glass Industries, Cement and Refractory manufacture, Induction Heating and Sintering operations.

Process Sensors? ?PSC Spot Software? supports sensor set-up, multi-tasking, graphic display of temperature trends, and data logging, and in general allows the user to customize the sensor to the application.

Detailed specification information can be found at