Liquid Solids Control, Inc.

We provide continuous In-Line measurement of concentration, typically displayed as: %, % Solids, Brix, RI, or various engineering units.

We are known around the world for unique innovation without compromise, sophistication while maintaining user simplicity, and superb service to our extremely wide customer base. Serving all major Pulp and Paper industries.

Typical applications: Pulp & paper Industry
  • Heavy black liquor solids
  • Weak black liquor solids
  • Red liquor solids
  • Brown stock wash water
  • Caustic dilution
Typical applications: Chemical Industry
  • Various acids; sulfuric, hydrochloric, nitric, etc.
  • Urea, urea formaldehyde
  • Caustic, caustic soda
  • DMA/DMF water blend
  • Styrene – ethylbenzene
  • Acrylic, acrylamide
  • MEK, toluene
Typical applications: Miscellaneous Industry
  • Glycerine, glycol
  • Salt, brine, vinegar
  • Latex, cooked starch
  • Lubricating oils

Our refractometers measures dissolved solids (soluble solids) using the “critical angle” technique (an interface measurement of refractive index). This measurement technique is not sensitive to suspended solids, turbidity, entrained air, viscosity, color, transparency, opacity, or flow rate, and the output readings are automatically corrected for variations in process temperature. The electronic circuitry includes a signal output, adjustable in both frequency and duration, for automatic washing of the sapphire sensing window face, when/if required. The measurement is displayed in the most useful terms for that particular application. The most common read-out units are % Solids, Refractive Index and TTA.

Model 1022 = The Ultimate in Reliability

With keen focus on functional reliability – employing a truly dependable and accurate system of the highest quality – LSC again demonstrates its continual leadership and is stepping out front offering the Model 1022 Automatic Liquor Divert System. Contributing to LSC’s extensive experience in the design and development of this equipment were many invaluable suggestions and mandates from several of the most prominent users/customers within the Pulp and Paper Industry. The LSC Model 1022 performs all necessary operational functions, including a number of “first ever” features, and fully complies with all recommendations of B.L.R.B.A.C.

With all hardware and software designed specifically for this application, the Model 1022 is an Automatic Liquor Divert System well ahead of its time, equally appropriate as a devoted standalone system (operates the Divert Valve directly) or integrated with a modern DCS or Burner Management System through various discrete dry contacts.

  • Dual solids measurement dependability “Smart Wash” automatic prism wash
  • Extensive reporting capabilities – all changes/events logged with time and date Exclusive – “first-out”/sequence report
  • Redundant operational features No simple arbitrary “disable” mode
  • All automatic divert features are retained during single refractometer operation Automatically removes a refractometer from operation when deemed necessary
  • Internal display screen for settings, diagnostics/troubleshooting and history Hard copy option (printer available) of all settings, alarms, and logged events/history
  • Intelligent fluorescent display (external) located on enclosure or on operator console Fully complies with the recommendations of Black Liquor Recovery Boiler Advisory Committee
  • It also comprise a gate adaptor assembly that can be added to effectively enable client to perform prism cleaning functions while actively running the process, without interruptions.
On-Line Measurement of Dissolved Solids
Model 326 Introduction

Liquid Solids Control is stepping out front, once again, with the Model 326 Refractometer.It offers a large 8.4″ LED Touch- Screen Display, as well as, an Ethernet connection for remote access via a web browser (we recommend Firefox).Providing a direct link to all of the instrument’s information, the Model 326 gives the customer the flexibility and convenience of interfacing with the unit from any location within the plant’s network (instrument shop/maintenance shop, control room, etc.).Furthermore, when needed, your IT department can set-up a VPN allowing the LSC factory to troubleshoot your refractometer remotely, saving you time and money.For customers that do not have their instruments networked, we have incorporated a USB port which allows the technician to off-load all diagnostic files (history, event alarms and calibration files), so that they can be e-mailed to LSC for troubleshooting assistance.

Engineers / Technicians will simply touch the large, user-friendly icons to change and/or view any of the parameters of the refractometer.

Multiple-level, customer-defined pass-word protection allows limited access to key operational and diagnostic functions.


Liquid Solids Control provides solutions for all installations.A variety of end fittings and flanges are readily available to complement the Model 326 process refractometer.

Sanitary Sensor

The In-Line Sensing Head is designed for sanitary applications. It is encased in a strong, waterproof (sealed) stainless steel housing and is completely maintenance free.

Prism Wash Sensor

The In-Line Prism Wash Sensing Head comes with an industrial wash nozzle and check valve.This ensures the prism stays clean on tough applications.

Insertion Probe

The probe is designed to be installed on tanks, vacuum pans and large pipe lines.They can be supplied with industrial or sanitary flanges. A prism wash nozzle is available when required.

Pipe Section

The Pipe Section is used to mount our in-line sensing head directly into the process line.They are available from 3″ to 18″ in diameter and can be supplied with or without industrial flanges (ANSI, DIN, JIS).

Valve Body

The Valve Body is typically 2″ to 4″ in diameter and with industrial flanges for general industry use, or sanitary flanges for use in food processing applications.


The Flow-Thru-Block is used in smaller process lines from 1/8″ to 3″ diameter.Threaded NPT Female connections, Industrial Flanges and Sanitary Tri-Clover Flanges are available.


The Model 326 Process Refractometer can be used to improve the entire efficiency of the “Kraft” liquor process, from the brown-stock washers, through the multiple-effect evaporators, concentrator, recovery boiler and even the dissolving tank.

Model 326 Process Refractometer

The Model 326 Process Refractometer can be used to improve the entire efficiency of the “Kraft” liquor process, from the brown-stock washers, through the multiple-effect evaporators, concentrator, recovery boiler and even the dissolving tank.

Key Facts:

Optimizing consumption of pulp chemicals.
  • Improve capacity of Evaporator/Concentrator.
  • Increase Recovery Boiler run-time and safety.
  • Typical Applications:

    • Heavy black liquor solids
    • Weak black liquor solids
    • Red liquor solids
    • Stock washer
    • Caustic dilution
    • Green Liquor
    Gate Adaptor

    The Liquid Solids Control Gate Adaptor provides the means for simple and quick removal of a sensing head from an active black liquor process pipeline, while ensuring the ultimate in safety.This dedicated unit eliminates the need for costly “By-Pass Loops”, which tend to be a bother by either leaking or plugging and even unscheduled process line shutdown to allow for maintenance.

    The gate adaptor (duplex 2205) employs a completely captive slide plate, mechanically sure, operated by an eccentric cam.Operation of the Gate Adaptor is accomplished by turning a 1″ (25 mm) hex operator just under 1/2 turn.Double Teflon seals are provided against both sides of the slide plate.

    The Gate Adaptor provides for an external lock “fully open” or locked “fully closed” additionally providing positive and physical indication of “fully open” or “fully closed”.

    Prism Wash

    The Model 326 Transmitter can be programmed to wash the sensing window (prism) on a time basis with steam or water.The 326 incorporates Smart Wash Technology, which means it monitors itself and self-adjusts to wash for only “as long as necessary”, eliminating most prism wash maintenance problems.


    The LSC Model 326 offers accurate in-line concentration measurements in the chemical, petrochemical and other various industrial process applications.Continuous monitoring enables uniform product quality and minimizes waste, as well as provides instant feedback on any process changes.

    Linear and Non-Linear Applications

    There are hundreds of ideal applications for process refractometers within the chemical and petrochemical industries. Some process measurements are linear, and some are not.The Model 326 has the ability to linearize/shape, or reverse, any customer’s product characteristics.This allows the process refractometer to track and produce accurate concentration measurements of products with a non-linear refractive index curve.Multiple linearized calibration tables may be stored and selected, as required.If desired, the measurement units, calibration, and correction points can selectively be changed at will, via the user-friendly touch-screen or remote web browser interface.The 4-20 mA output signal is automatically calibrated to the selected measurement range.

    Intrinsically Safe Installations

    Through the use of intrinsic safety barriers, the LSC Model 326 Sensing Head (either the in-line style or insertion probe) can easily be operated in a hazardous area, being intrinsically safe to the highest level.The sensing head is classified as a “Simple Apparatus”.Our system’s unique design allows for the sensing head to be located up to 500 feet (150 meters) away from the electronic enclosure.This exclusive feature eliminates various cumbersome problems associated with distance limitations that can occur when using other process instruments.The flexibility of the Model 326 allows the user to locate the electronics enclosure in the most convenient “safe zone”.

    Dimensions & Weights

    All flow cells that Liquid Solids Control manufacture are tailor-made to the requirements of the customer’s installation. This includes the line size, connection type and material.Typical length for single flanged pipe sections is 18″ face to face.Dual pipe spools are 28″..

    LSC Model 326 Technical Specifications

    Input Power Required

    100 to 240 VAC, 50/60 Hz, < 25 Watts

    Refractive Index Range

    % Solids or Brix Range

    1.3000 – 1.6000

    0 – 100

    Span (calibration)













    *May vary with some process materials or applications


    ±0.5% of selected span range



    Speed and Response

    500 milli-seconds

    Process Temperature Range

    -25º to 150º C

    Temperature Compensation

    Automatic (Can be calculated for any range)

    Process Line Pressure

    Up to 1000 PSIG (68 Bar)

    Interconnecting Cable Length

    1,500 feet maximum (455 meters)

    Process Measurement Outputs

    Standard and included

    Isolated 4 – 20mA DC, (15 V compliance) Isolated 0 – 10 VDC

    Optional Local Display

    8.4" Touch Screen (800×600 RES)

    Remote Communication

    Web Browser via Ethernet

    Process Temperature Output

    0 – 10 VDC

    Diagnostic Port


    Alarm Set Points


    Relays normally energized or normally not energized LO / HI set points are fully adjustable

    Prism Wash

    Automatic  “Settable”

    Wetted Material

    Duplex 2205, 316SS, Alloy 20, Hastelloy-C, Teflons, Other materials available upon request


    Sapphire (Highest Industrial Grade)

    Processor Enclosure

    Polypro Nema 4X Enclosure with SS Latches

    Electronic Enclosure Ambient Temp.

    Up to 50º C


    (1) 2205 Duplex and 316LStainless Steel are used as our standard wetted material.Many other materials are available for specialty applications.(2) Due to ongoing Research and Development and product improvement, all specifications are subject to change

    Two year warranty

    The Model 326 Process Refractometer manufactured by Liquid Solids Control, Inc. is warranted against any/all defects in materials, components, and workmanship for a period of two (2) years from the date of shipment.In the unlikely event that this product proves to be defective during the warranty period, return it to Liquid Solids Control, Inc., and it will be, at our discretion, repaired or replaced free of charge for both labor and parts.

    Have a question about LSC?

    Please contact us for more information.