Hypo Batch Controller with Temperature Indicator - Powell ...

Powell
Fabrication & Manufacturing Inc
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.
The batch controller has been designed to lockout the chlorine valve so that it can not open
automatically after the ORP shutdown alarm has been reached. If the millivoltage drops
below the shutdown set point and the operator turns the chlorine valve control switch to the
"release" position and then back to the on position, the shutdown alarm will reset to the
normal mode and the chlorine valve will turn on. The operator has full control of the optional
chlorine valve and can turn it on or off as desired. Since the alarms for both meters are
adjustable, the operator has a choice on the alarm and shutdown points of each meter. The
temperature alarm does not lock out the automatic valve and will automatically reopen the
chlorine valve when the batch cools.

Typically, the batch controller is placed at a convenient operator location with the alarm horn
remotely mounted in any location within hearing range. The electrodes are usually placed on
the suction side of a recirculation pump for the batch, or through a tank wall with field
fabricated and installed bulkhead fittings. Special electrode holders will be designed for any
application.
Installation
NOTE: Recommended installation of the digital batch controller provides for dual ORP
readings from the same bleach tank, causing the redundancy for an independent backup
input and alarm of the batch chlorination. Wiring or plumbing, which defeats the backup or
redundancy of the second meter reading of an individual batch, is not recommended by
Powell Fabrication & Manufacturing, Inc.
1. The electrodes are installed into the pipe line using PVC electrode adapters that are
designed to screw into a ¾" NPT thread. These adapters can be installed into PVC
cross with threaded bushings or by drilling, taping, and gluing the PVC pipe. The set of
electrodes should be installed in the suction side of the recirculating bleach pump line,
and should be in the pipe line so that the line will always be completely full when the
bleach is pumped. Optionally, the ORP ring will fit between flanges.
The electrodes can also be installed into the chlorination tank and since there are many
ways this can be accomplished, please call the plant for suggestions. Install the set of
positive and negative electrodes opposite each other as described by the electrode
instruction sheet.
2. Insert the threaded titanium well into the piping to the tank. The well has a ½" NPT
thread. Make sure the well is in the main stream of bleach flow or tank wall for good heat
transfer. Often this is accomplished by inserting a threaded bushing into an end outlet of
a tee. Make sure there are no obstructions the well will contact when screwing the
titanium well into the adapter. Thread the spring loaded RTD probe holder into the well a
little more than hand tight.
3. Locate the batch controller in an area of choice. The temperature of the area must
be between 14 0 F and 140 0 F for the meters to operate correctly.
4. The positive and negative wire from the first set of electrodes attached to the low voltage
terminal board of the batch controller low voltage terminals #1 and #2 using #16 THHN
copper wire.
5. The positive and negative wire from the second set of electrodes attached to the low
voltage terminal board of the batch controller low voltage terminal #3 and #4 using #16
THHN copper wire. Connect temperature probe wiring as shown on the electrical print
from the RTD probe to low voltage to terminals #5, #6, and #7.
6. The horn is located in the area of choice. Conduit is connected from the batch
controller to the horn. The horn is connected to the high voltage terminals #4 and #5.
7. The chlorine shutoff valve, power and limit switch, optional, is wired in conduit to the
batch controller. To indicate valve open position, the limit switch is connected to the high
voltage terminal #8 and #9. The power for the chlorine liquid valves is connected to the
high voltage terminal #6 and #7.

8. The 120-volt control power for the unit is connected to terminal #1, #2 and #3 on the high
voltage terminal board according to the terminal board connection diagram.
9. Without the chlorine car turned on, put 120-volt power to the batch controller and adjust
the meters to the desired settings. The meters have been factory programmed,
however, the alarm and shutdown points may need to be adjusted. The meters are
adjusted to the desired set points by entering keystrokes into the lower front panel
keypad. Press "D" key consecutively until desired parameter appears. Pause until the
set point appears, then press the ">" key to select the next unit to be changed, and the "^"
key to obtain new value. When set point is correct, press the ">" key until the right most
digit flashes and press the "E" key to store the new value into memory. Pressing "X" will
cancel the current operation and return the display to the scaled input value.
Example:
Action
Press "D"
Release "D"
Press "D"
Release "D"
pressed)
Press "D"
Release "D"
Press and release >
Press and release ^
Display
"I" Input
(MVDC Reading)
"P" Peak
(Peak value since last time "X" was
"S1" Set point one
(Setpoint one)
Flashing Digit
Scroll to desired digit
*Repeat previous steps until desired set point is displayed.
Press and release E
To enter value and resume normal display
Press "X"
To return to normal display at any time
10. After the alarms are set, prepare your caustic dilution and begin chlorination. Titrate
your bleach as you chlorinate and make sure that the alarm and shutdown points are set
to achieve the results you desire.
Normal Set Points
Please note the batch controller will control the end point of the bleach reaction since the
lower the residual caustic, the higher the voltage from the electrodes. Depending on the
strength of bleach you manufacture, the end point voltage will vary.
The only way to determine the correct end point voltage for your system is to produce a
batch of bleach by the titration method and record the millivoltage at the end of the batch.
Using this end point for a reference, the controller set points can be adjusted.

Below are two examples for reference only. The set points of the alarm contacts are your
choice.
Example #1
Chlorine Control Meter (left unit)
Set Point 1 - 530 MVDC
Results in alarm only
Set Point 2 - 540 MVDC
Results in shutdown of optional chlorine valve and sounds alarm horn.
Chlorine Safety Meter (right unit)
Set Point 1 - 550 MVDC
Results in alarm only
Set Point 2 - 560 MVDC
Results in shutdown of optional chlorine valve and sounds alarm horn.
Temperature Meter (Bottom Unit)
Set Point 1 - 85 o F
Results in alarm only
Set Point 2 - 87 o F
Results in shutdown of optional chlorine valve and sounds alarm horn.
The above example is set up to have the system operate from the control meter for ORP and
use the contacts of the safety meter for redundant control.
Example #2
Chlorine Control Meter
Set Point 1 - 560 MVDC
Results in alarm only
Set Point 2 - 530 MVDC
Results in shutdown of optional chlorine valve and sounds alarm horn.
Chlorine Safety Meter
Set Point 1 - 570 MVDC
Results in alarm only
Temperature Meter (Bottom Unit)
Set Point 1 - 90 o F
Results in alarm only
Set Point 2 - 85 o F
Results in shutdown of optional chlorine valve and sounds horn.
Set Point 2 - 550 MVDC
Results in shutdown of optional chlorine valve and sounds alarm horn.
The above example show an important feature of the controller and that is the low alarm, SP1,
can be set higher than the high alarm, SP2. Therefore, as in example #2, the controlling meter
can be set to alarm and shutdown the chlorine valve by SP2 contact first, or the safety meter
would shutdown the system using its SP2 contact. Effectively the low alarms in both meters are
not being used in this example.
As mentioned above, setting of the contacts is the operator’s job, but if you have any problems,
please call us.

Specifications
Power Requirements
120 volt, 1 phase, 15-amp circuit
NOTE: Cabinet is internally fuse protected by 2-5 amp fast blow fuses.
Electrical Relay Contacts:
Voltage Meter Range:
Temperature Meter Range:
-336 o to +1560 o
Inductive at 35% P.F.
Continuous - 5 amps
Make - 15 amp.
Break - 1.5 amps.
Resistive at 75% P.F.
Continuous, Make, and Break -5 amps
0-2 VDC with two alarm contacts
External wiring provided by customer: Control power, cabinet to electrodes and
thermocouple, horn and optional chlorine
shutoff system.
Standard Equipment:
-- Two digital ORP controllers, one digital temperature meter in NEMA 4 case.
-- Alarm horn.
-- Two silver electrodes with Kynar holder and PVC dust cap.
-- Two platinum electrodes with Kynar holder and PVC dust cap.
-- 100 ohm RTD probe with titanium well PVC electrode holder (Four required).
-- Instructions and set up procedure; wiring diagrams.
Maintenance
As consecutive batches are chlorinated and titrated, results are compared with the set point
values, the end point alarm will begin to drift indicating dirty electrodes. Refer to electrode
maintenance to clean and replace electrodes.
Powell
Fabrication & Manufacturing Inc
740 East Monroe Road • St. Louis, MI 48880
Phone 989.681.2158 • Fax 989.681.5013
e-mail info@powellfab.com • www.powellfab.com
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