Hypo Batch Controller with Temperature Indicator (Digital ORP/ORP/Temperature System) 2400 Series

Hypo Batch Controller with Temperature Indicator (Digital ORP/ORP/Temperature System) 2400 Series

Introduction

A sodium hypochlorite batch controller has been designed for bleach producers. The batch controller measures and displays the chlorine content of the bleach on a solid state digital D.C. millivolt meter as the sodium hydroxide is chlorinated. The sodium hydroxide must be at a predetermined strength before chlorination of the batch is begun. The batch controller utilizes two ORP meters that perform a redundant safety feature. If the control meter should fail, the safety meter will still alarm. A temperature meter has been installed to alarm and shutdown on high batch temperature. The digital meters are installed inside of a 30"h x 24"w x 8"d NEMA 4 case with a window in the front of the cabinet for easy visibility of the meters.

The oxidation-reduction method utilizing silver and platinum electrodes immersed in the bleach solution measure the chlorine content of the bleach. The standard electrode holders are constructed of PVC plastic and are designed for 2" or larger pipe. An optional holder designed to mount between any size pipe flange is available. Two complete chlorine control loops are provided with the batch controller, one is referenced as "Chlorine Control Indication", and the other as "Chlorine Safety Indication." As the sodium hydroxide is chlorinated, a voltage is produced proportional to the degree of chlorination and is displayed on the digital D.C. millivolt meter, with two adjustable set points. When the chlorine is added
to the sodium hydroxide, the voltage increases until the low set point of the chlorine control meter is reached, thus turning on the chlorine control alarm light and alarm horn. Usually, the low set point is used only to notify the operator that the batch is nearing completion. After the alarm horn sounds, it is silenced by the alarm silence button. The first set point will sound a horn, which may be silenced by the operator.

After the operator silences the alarm, he can reduce the rate of chlorine flow being added to the batch if he desires. He then waits for the chlorine control shutdown light to turn on and the alarm horn to sound. If the optional automatic chlorine valve is installed, it will shut off when the chlorine control shutdown activates, and indicate valve open on the controller pilot light. If an automatic valve is not installed, the operator is expected to manually shut off the chlorine at this point. When the temperature alarm is reached the operator needs to slow the rate that chlorine is added to the system. If the temperature continues to raise the shutdown will close the optional chlorine valve.