FAQ'S Below are answers to some of the frequently asked questions (FAQ'S) about the Density Analytics Electronic Hydrometer, Specific Gravity/Liquid Density Meter, Monitor, Controller. Who is the inventor, developer and manufacturer of this device? This SGU-100 digital density meter, monitor, controller was invented, patented and developed by Density Analytics, L.L.C. The device is manufactured in the USA and is distributed globally.
What is the operating principle of this device? The density meter is basically a pure physics device that operates on the buoyancy principle. The submersible probe contains a mobile float that moves up and down in accordance with the density of the liquid. The float holds a bar magnet that actuates a patented Hall Effect linear proximity sensor. The signal output from the probe is processed by the connected electronic module that provides a calibrated digital read out of the liquid density in addition to an optional 4-20 ma analog output.
How does this device compare in functionality to similar devices? This Density Analytics density meter has the capability of doing a remote, in-tank, real time, continuous, measure, monitor, record and control of specific gravity/ liquid density. It is the only device on the market that has all these attributes and completeness of functionality. Hand held, desk top, or in-line devices cannot match the total functionality of this device.
How robust is the device? The density meter probe is immune to damage. It can be dropped on a floor, will not break, and still be operational – very much unlike hand held, desk top, and in-line devices which are considered to be physically and electronically very fragile devices.
How does one calibrate the device? The density meter electronic module operates on 120 vac power and contains a push button programmable meter. The user can very easily calibrate and program the meter at any time to read the output density in the users preferred engineering units – sgu, Baume, % concentration. The density range is customized to the application. These other devices use mostly Coriolis sensors-- these sensors are very fragile, not robust, are very easily breakable. In addition, they rely on an electronically activated tube that captures the liquid for processing. Any sticking or adhesion of previous liquids in the tube will alter the physics of the tube and contaminate and violate the accuracy of the readings. These devices cannot be easily checked and calibrated for the user’s particular application.
Can the probe be easily cleaned? The density meter probe contains only one moving part – a mobile float that is constrained by two stainless 316 springs. The probe can be easily dissembled, cleaned by swishing in clean water, and reassembled.
What are the fabrication materials and whetted parts? The probe and float are fabricated from engineered chemically resistant materials: CPVC housing, PVDT cable strain, 316 stainless springs, epoxy or silicone encapsulation and PVC or Teflon probe cable. These materials are chosen so that the probe is chemically resistant to hostile liquids.
What does the 4-20 ma analog output do for the user? In addition to a digital readout of density, the terminals on the back of the density meter electronic module provide a 4-20 ma analog output signal. This signal can be interfaced with a PLC controller to measure, record, monitor and control the liquid density by providing a signal that can turn valves on and off to maintain a particular user target density. In addition, this signal can be used to trigger process alarms for maximum or minimum density benchmark requirements.
Can the probe alone be purchased separately for direct PLC interfacing? Yes. The probe can be purchased separately. It operates on 5 vdc and provides a 0 – 5 vdc signal output to a simple 3 wire connector (power, ground, and signal) at the end of the probe cable. A density/voltage calibration curve is supplied with the probe.
Can device be used for detecting vertical density gradients in holding tanks? Yes. This density meter is an in-tank device and it measures and monitors the liquid density in the immediate location/vicinity of the probe. Therefore, it can be vertically lowered to detect vertical density gradients in holding tanks. This is useful for getting a more accurate measure of liquid inventory /assets in a holding tank. None of the above mentioned devices – hand held, desk top, and in-line -- are capable of doing this.
What type of mounting is used for this device? The remote, submersible probe is an in-tank sensor device. It can be simply hung or attached to a wall in the tank. Probe must be vertical and completely covered with liquid (11” probe height). The probe is atmospheric pressure invariant and can be submersed at any depth in the liquid.
How easy is it to incorporate this device into an existing application? Since the probe is connected to a submersible cable, simply hanging the probe in a process application tank is sufficient for the probe to have intimate contact with the liquid under observation. For this reason, we say this Density Analytics density meter is easily retrofittable to existing applications.
What are typical user applications? We have over 300 satisfied users and repeat users of this Density Analytics density meter device -- they have a myriad of applications. Morton Salt uses our devices to monitor salt concentration in evaporation basins. ESAB Welding (www.esab.com) uses our devices to monitor the density of lubricants in their welding machines. The Savannah River Nuclear Facility (www.srremediation.com) uses our devices to monitor the liquid density in their highly radioactive holding tanks. The metal finishing company Technic uses our devices to monitor the liquid density in a metal passivation/ cleaning process. Check out the web site for a listing of many more applications. What kind of product service can we expect? Density Analytics is the inventor, producer and distributor of this functionally superior density meter device. You can count on responsible product service and a support staff that is very familiar with the physics of operation of the device, and who will provide help and guidance with specific application/installations.