Connection of Sensors to Valves Is Chemical Plant’s Formula for Total Quality
To obtain its ISO 9000 Certification, State Chemical — a division of State Industrial Products — replaced its deteriorating batch control systems with Easy LINK™ solutions consisting of Burkert Type 8035 inline flow transmitters with digital display, direct-linked to Burkert Type 2000 Y-pattern valves for precision ON/OFF control.
Located in Cleveland, Ohio, State Chemical now automatically controls all bulk and mixed chemical transfers by using the programming capabilities of Type 8035 for automatic or manually entered batch volumes. This cost effective approach saves material by reducing the plant’s overfill rate from more than 5% to less than 1%, and reduces human interaction with chemicals during the transfer process, offering a system payout in two months.
Inside the 30,000-square-foot plant, operators turn out numerous chemical batches per day. State Chemical manufactures several thousand industrial cleaning products including solvents, hand soaps, floor waxes and disinfectants. All finished goods are water-based and range from highly corrosive, acidic products with a pH of 0.4, to boiler water treatments which are very basic, and may have a pH of 13.
Depending upon which of approximately 300 batch recipes are being made, the compounding process takes place in a 250- to 3,700-gallon stainless steel compounding tank. First softened water, then raw chemicals are dispensed in preset quantities and mixed. Following quality control approval, each batch is filled into finished goods which range from pint and gallon bottles to bulk pails and drums.
Until recently, the plant had been getting by with outdated equipment and technology, according to Tim Gale, State Chemical production engineer.
“We determined that new process control equipment would have a significant impact on our product quality. To become ISO 9000 certified, we had to have equipment that can be calibrated. The positive displacement meters we had been using for 10 to 15 years had become so inaccurate that they could no longer be calibrated,” Gale explained.
“That meant we had to manually measure the level of fluid in the tank to determine how much was actually dispensed. We were losing a lot of fluid so we were adding more than was necessary. The old valves leaked and didn’t always stop, causing a lot of spilled product,” he said.
The decision to go with a Burkert fluid control solution was based on State Chemical’s success with the Burkert Type 8035 inline digital flow transmitter for process water dispensing at another site.
So with ISO 9000 certification as the goal, Gale contacted his Burkert distributor, HLT Inc. in Parma, Ohio. After several engineering meetings, he and Mike Coughlin, of HLT agreed on a solution utilizing Burkert Type 8035 inline batch controllers with Burkert Type 2000 Y-pattern valves for controlled volumes. Four wall-mounted transmitter/valve combinations and several remote transmitters are used for solvent and process water dispensing. Another flow transmitter and valve are mounted on a portable transfer unit supplied by HLT for controlled filling of finished goods.
The control process is the same for each batch. A Type 8035 batch controller, consisting of an electronic module with brass fitting, meters the flow of softened process water in 2-in. lines into the mixing vessel. The quick, quarter-turn interface between the fitting and sensor facilitated the upgrade without the need for additional cables or plugs.
Similarly, solvents are metered in precise amounts from 4,000-gallon underground storage tanks, using Type 8035 with PVDF fittings. Each transmitter is programmed to deliver a particular material via a Type 2000 valve, directly connected to the sensor.
Equipped with a large LCD digital readout, the Type 8035 displays both flow rate and volume with up to seven different programmable batches. TEACH-IN and Test Simulation functions allow setup without actually operating the flow system, features critical to State Chemical’s ability to meet the demands for calibration under ISO 9000. The plant calibrates the Burkert Type 8035 flow transmitters on a quarterly basis, documents the calibration using a calibration records database and tracks its yields, for total quality control.
Type 8035 has an open-cell, in-line rotor sensor built into the body with ceramic bearings. When liquid flows through the line, the in-line rotor rotates, inducing a frequency in the transducer proportional to the flow. Using standard relay output, the flow transmitters are linked directly to Burkert Type 2000 Y-pattern valves, creating individual ON/OFF control loops that automatically add the proper materials to the batch in the right amounts.
The Type 2000 valves feature two sets of self-compensating PTFE seals to keep all process materials from the actuator mechanism. Positive valve sealing is assured through the use of an articulated seat, also made of PTFE. Like the flow transmitter, the Type 2000 also is easy to install. Its compact actuator lets these valves fit in tight spaces never considered possible with traditional ball valves. Installation is made simple because the valve’s pneumatic inlet ports and pilot valve can be rotated 360° around its circumference.
State Chemical’s portable unit is used for mixed chemical transfer and filling. It contains a diaphragm pump and pulsation dampener, a Burkert Type 8035 batch controller and Type 2000 valve. Type 8035 automatically dispenses the correct amount of filled product into the container and then closes the valve.
The new system lets operators be more productive. “Formerly, the operator couldn’t do anything but stand there and watch the drum fill, and then he had to go around and label the drums. Now he can label the drum while it fills, paying no attention to the filler whatsoever,” Gale explained.
Moreover, filling 5-gallon pails used to be stressful on the operators’ backs, requiring them to remain bent over while the pail filled. Now they just insert the hose and the system starts and stops automatically.
Following ISO 9000 Certification of both its Cleveland and Tulsa, Oklahoma plants, State Chemical is considering adding Burkert steam valves for temperature control. According to Gale, the greatest benefit would be the elimination of scrap and rework because the mixing tank has been overheated or the wrong material added to the chemical batch.