Water softener abstract
A novel electronic control circuit which includes a probe for detecting
the conductivity in ion exchange material in a water softener and
wherein the probe includes two pairs of spaced electrodes which
are connected in a bridge circuit and connected so as to close an
energizing circuit and latch it until it is time for regeneration
and wherein the regeneration is controlled so that it will occur
only at those times which are preset as, for example, during the
night when the regeneration will not interfere with normal use of
the water supply.
Water softener claims
We claim as our invention:
1. Apparatus for regenerating the ion bed of a water softener having
a regenerating means and a recycling control connected to control
the regenerating means comprising, two pairs of spaced electrodes
mounted in the ion exchange bed and their resistivity depending
on the condition of the ion exchange bed, comparing means connected
to said pairs of electrodes to compare their resistivity and when
the difference exceeds a predetermined difference the output of
said comparing means changing condition, a latching means connected
to said comparing means and latched to indicate regenerating of
the ion bed is necessary for a period of time until said regeneration
has been completed, and a timing means capable of being set to selected
time periods connected to said recycling control and to said latching
means to cause regenerating of said ion bed during a preset period
when said latching means is latched, including a reset means for
resetting said latching means and comprising a time delay means
connected between said latching means and said pairs of spaced electrodes.
2. Apparatus for regenerating the ion exchange bed of a water softener
having a regenerating means and a recycling control connected to
control the regenerating means comprising, two pairs of spaced electrodes
and at least one mounted in the ion exchange bed, a bridge circuit
including said pair of electrodes, an A.C. power supply signal applied
to said bridge circuit, a first comparator receiving a first input
from said bridge circuit, a reference signal supplied to said first
comparator, a relay with switch contacts operated by said first
comparator, a latching circuit connected to said relay to maintain
it energized, a timing means capable of being set to selected time
periods, and a recycle switch controlled by said timing means and
said recycle switch and the switch contacts of said relay connected
in circuit with said recycling control including a reset switch
connected to said latching circuit for resetting it and wherein
said reset switch is controlled by said timing means to reset said
latching circuit after said ion bed has been regenerated and including
a time delay circuit connected between said first comparator and
relay so that said relay is operated only if the output of said
first comparator indicates that regeneration should occur for a
fixed time period.
3. Apparatus according to claim 2 including a second comparator
receiving the output of said time delay circuit and a reference
signal and its output connected to said relay.
4. Apparatus according to claim 3 wherein said latching circuit
includes a third comparator which receives a reference signal and
the output of said second comparator and supplies its output to
the input of said second comparator through said reset switch.
5. Apparatus according to claim 2 wherein said time delay circuit
includes a capacitor and resistor.
6. Apparatus according to claim 5 including unilateral direction
current means between said capacitor and said first comparator.
Water softener description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to water softeners and in particular
to a novel detecting and controlling system for a water softener.
2. Description of the Prior Art
Probes to indicate resistance changes in ion exchange material
in water softeners are known as shown by issued U.S. Pat. No. 3373351
to Stanley F. Rak and resistance sensing probe systems are disclosed
in U.S. Pat. No. 3159573 to H. D. Ritchie. However, these systems
of the prior art are designed to immediately rejuvenate and recondition
the ion exchange resin which can occur at times when it is desirable
that water be supplied from such system.
Thus, in the prior art various systems have been known for causing
regeneration of the resin bed of a water softener such as manual
regeneration, or regeneration based on a control device which initiates
regeneration at fixed given intervals of time. The problem with
these two systems is that the regeneration may occur before it is
needed or alternatively may not occur quickly enough and the water
is not properly softened toward the end of the interval. A third
system for water softening is based on a control which causes water
softening when the condition of the output water and/or the resin
bed indicates that regeneration should occur. The problem with this
type of system is that regeneration can occur at periods when there
is a high demand for soft water and during regeneration generally
the soft water is not available and the unsoftened is bypassed by
the water softener.
Other systems have utilized a pair of water softening or water
conditioning apparatus each having separate control units and in
which the units are interconnected with interlocking devices to
prevent both units from being in the regenerating condition at the
same time and an example of this type of system is disclosed in
U.S. Pat. No. 3675041. Of course, this type of system is expensive
in that two complete systems are required.
SUMMARY OF THE INVENTION
The present invention relates to a water softener system and control
wherein a resistance sensing probe including two pairs of spaced
electrodes are mounted in the ion exchange bed of the granular material
carrying water softening ions to detect the condition of the ion
exchange bed and when the condition is such that rejuvenation should
occur a control circuit is placed in a latched condition to command
rejuvenation. However, the control remains in the latched condition
and rejuvenation does not occur until a preset time of day as, for
example, during the night in order to assure that normal usage of
water is not interrupted during the daytime. After the rejuvenation
has occurred the circuit is reset ready to again detect the condition
which requires rejuvenation.
Other objects, features and advantages of the invention will be
readily apparent from the following description of certain preferred
embodiments thereof taken in conjunction with the accompanying drawings
although variations and modifications may be effected without departing
from the spirit and scope of the novel concepts of the disclosure
and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a water softening system with certain
portions cut away; and
FIG. 2 is an electrical schematic of the control system of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a water conditioning or softening apparatus
or device generally indicated as 10 which has a control unit 11.
The water conditioning apparatus 10 includes a tank 12 containing
a bed 13 of suitable ion exchange resin. So as to provide water
to the tank, a water supply line 14 is connected to the valve housing
16 which passes the water through a pipe 17 which extends to the
tank 12. The water passes down through the bed 13 and is removed
by a pipe 18 through the valve housing 16 to a line 19 which supplies
the softened water to the water system. A conduit 21 extends from
the valve control to a brine tank 22 which contains salt for forming
the brine. A drain conduit 23 is also connected to the valve housing
16 and is connected to a suitable drain.
The control valve structure 16 may be on conventional type as,
for example, described in U.S. Pat. No. 3926071 and may be of
either the two or five cycle type which systems are well known to
those skilled in the art. The recycling control 24 controls the
recycling and might be, for example, such as described in U.S. Pat.
No. 3926071 and in the present invention comprises an electronic
control 26 which assures that the recycling does not occur except
at predetermined times as, for example, between 2:00 and 6:00 A.M.
so that rejuvenation does not occur at other times when is desired
to have softened water supplied for use.
The electronic control 26 of the present invention detects when
rejuvenation of the resin bed should occur by the use of two pairs
of vertically mounted electrodes R.sub.s and R.sub.r which are mounted
in a suitable holding probe unit 27 which extends down into the
tank 12 and are vertically spaced relative to each other and by
detecting the resistivity determines when rejuvenation should occur
and energizes a latching circuit. However, in the present invention
rejuvenation of the resin bed is not immediately commenced when
the condition is detected which indicates rejuvenation should occur,
but rather the circuit of the invention remains in a latched condition
until a time which has been preset during which it is desired to
rejuvenate the resin at which time such rejuvenation will occur
and the detecting circuit will then be reset after rejuvenation
until rejuvenation is again required. In other words, in the present
invention as soon as the resistivity difference between the detecting
electrodes R.sub.s and R.sub.r is such that rejuvenation should
occur then the circuit of the invention is placed in a latched condition
and will remain in such latched condition until the resin is rejuvenated.
However, the rejuvenation will not be initiated until the preset
period as, for example, between 2:00 to 6:00 A.M. so that rejuvenation
doesn't occur at those periods when there is a demand for softened
water.
A pair of 60 cycle input power terminals 27 and 28 are connected
to the primary 29 of a transformer T1 which has secondary windings
31 and 32. A bridge circuit 33 includes a pair of resistors R1 and
R2 and a reference cell R.sub.r and a sensing cell R.sub.s connected
in a bridge configuration. The junction point between resistors
R1 and R2 is connected to one end of the secondary 32 and the other
end of the secondary 32 is connected to the junction point between
the sensing and reference cells R.sub.s and R.sub.r. The other secondary
winding 31 of transformer T1 has one end connected to the junction
point between resistor R2 and the cell R.sub.r and the other side
is connected to a diode D1 which has its other side connected to
an input terminal of a voltage regulator 34. The junction point
between resistors R1 and R.sub.s is connected to the negative input
terminal of an operational amplifier A1 which comprises a comparator
and which receives a regulated voltage V.sub.s which is supplied
from an adjustable wiper contact 41 which engages a resistor R4
which has one end connected to a lead 42 that is connected to the
other end of the secondary winding 31 of the transformer T1 and
also provides an input to the voltage regulator 34. A resistor R5
is connected between the other end of the resistor R4 and the voltage
regulator output lead 43. The output of the comparator A1 is connected
to the junction point between the secondary 31 and the diode D1
by a resistor R3. A diode D2 is connected to the output of the comparator
A1 and a capacitor C1 is connected between the other side of the
diode D2 and lead 42. A resistor R6 is connected in parallel with
the capacitor C1. A comparator A2 is connected to the diode D2 as
shown and receives a reference input voltage V3 through a resistor
R8 from lead 43 which is connected to the output of the voltage
regulator 34. An energizing relay 36 is connected from the output
of the comparator A2 to lead 44 which is connected between the diode
D1 and the voltage regulator 34. The relay 36 controls relay contacts
46 and 47 so that they are connected together when the relay 36
is energized. The contact 47 is connected to the recycling control
24 and the contact 46 is connected to a normally opened contact
48 of a switch 49 which is connected to the recycling control 24.
A cam 51 which is driven by a suitable clock motor is driven by
shaft 52 at the output of the clock motor 53. The cam 51 has a high
point portion 56 so as to close the switch contacts 49 and 48 during
preset time periods as, for example, between 2:00 and 6:00 A.M.
Thus, in the event the relay 36 has been energized so as to close
the relay contacts 46 and 47 such contacts will remain closed and
the relay 36 will remain energized by a latching circuit to be later
described and when the switch contacts 46 and 47 are engaged by
the energization of the relay 36 the time driven cam 51 will close
the switch contacts 48 and 49 thus initiating recycling through
the recycling control 24 so that the water softener will be recycled.
After recycling has occured, the high point of the cam 56 will move
out of engagement with the switch contacts 49 and 48 so that they
will open. The latching circuit includes a comparator A3 which is
connected to the output of the comparator A2 and which receives
a second input from the voltage regulator 34 from lead 43 through
resistor R8. The resistor R8 is also connected to the comparator
A2. The output of the comparator A3 is supplied through a resistor
R9 and a switch S1 to the input terminal of the comparator A2 to
reset it by momentarily opening switch S1 when R.sub.s equals R.sub.r
which indicates that the system has been rejuvenated. So as to open
the switch S1 after rejuvenation has occurred, a cam 61 with a high
portion 62 is also driven by the clock motor 53 and is mounted on
the output shaft 52 of the clock motor. The high portion 62 is phased
relative to the high portion 56 of cam 51 such that the switch S1
is only opened after the switch contacts 48 and 49 have been closed
for a sufficient time to allow rejuvenation of the resin bed which
condition also assures that the sensing cells R.sub.s and R.sub.r
will be at the same resistivity so that when the switch S1 is opened
the relay 36 will be de-energized opening the contacts 46 and 47
and the circuit will be reset until rejuvenation is required again.
The clock 53 may be driven by suitable AC power supplied to terminals
67 and 68.
The voltage regulator 34 may be a type LM 34 OT which produces
an output of 5 volts on lead 43 for example. The voltage comparators
A1 A2 and A3 may be type CA339 QUAD voltage comparator wherein
one of the comparators present in the unit is not utilized.
In operation, as the impedance of the sensing cell R.sub.s goes
up, the voltage V1 at the output of the bridge 33 will increase
and the positive half cycles of the applied voltage V1 from the
bridge 33 to the comparator A1 will exceed the reference set level
V.sub.s from potentiometer 41 and this will cause the comparator
A1 to clamp the voltage V2 at the secondary 31 during the positive
half cycles of the voltage V1. Since voltages V1 and V2 are in phase
and the positive half cycles of V2 charge the capacitor C1 through
the diode D2 when the voltage V2 is clamped by the comparator A1
during the positive half cycles, the capacitor C1 starts to discharge.
On the other hand, when the comparator A1 does not clamp the voltage
V2 the capacitor C1 is maintained in a charged condition.
The voltage across the capacitor C1 will start to decay and will
decay through the resistor R6 to ground and the voltage across the
capacitor C1 is supplied through the resistor R7 to the comparator
A2. When the voltage V4 at the input of the comparator A2 becomes
less than the reference voltage V3 from the regulator 34 through
the resistor R8 the comparator A2 will clamp the end of the relay
36 to the voltage V5 (ground) thereby energizing it. The voltage
V5 will be lower than the reference voltage V3 and comparator A3
will clamp the capacitor C1 to ground thereby locking the relay
36 in the energized position where it will remain energized until
the switch S1 is momentarily opened at a time when the sensing cell
and the reference cell have the same impedance.
The discharge time of the capacitor C1 can be set by selection
of a resistor R6 to a value of about 30 seconds so as to prevent
premature or false lock outs.
In the event the bridge is unbalanced in the reverse direction
so that R.sub.r becomes greater than R.sub.s nothing happens since
the voltages V1 and V2 at that time would be out of phase.
The resistor R9 protects the comparator A3 from a high inrush current
but is low enough in value to maintain the voltage V4 below the
voltage V3.
The bridge circuit consisting of the resistors R1 R2 R.sub.s
and R.sub.r is connected to the transformer secondaries 31 and 32
such that when the sensing cell R.sub.s becomes greater than the
reference R.sub.r (resistance) the bridge will be unbalanced to
produce an AC voltage V1 which is in phase with V2. The comparator
A1 receives the regulated voltage V.sub.s and the variable voltage
V1 such that when V1 is less than V.sub.s the positive half of the
voltage V2 will charge the capacitor C1 through the resistors R3
and the diode D2. The comparator A2 receives the applied voltage
V4 which is essentially the voltage across the capacitor C1 and
the voltage V3 is the reference voltage from the regulator and might
be, for example, approximately 5.0 volts and when V4 is greater
than V3 the relay 36 will not be energized.
The comparator A3 receives the applied voltage V5 which is high
and might be, for example, approximately 12 to 14 volts when the
relay is not energized and when V5 is greater than V3 no clamping
action occurs at the output of the comparator A3.
The diode D1 and the capacitor C2 provide for rectification and
filtering.
It is seen that this invention provides a novel electronic latching
control circuit for a water softener which assures that rejuvenation
of the resin bed will occur only when it is required. Furthermore,
in view of the cam 51 the circuit will recycle only during the
preset period as, for example, between 2:00 and 6:00 A.M. The reset
cam 61 will open switch S1 momentarily only after recycling has
been completed assuming that recycling was commanded by the relay
36.
A diode D20 is poled as shown in FIG. 2 and is connected between
lead 42 and V1. A capacitor C20 is connected in parallel with coil
36.
Although the invention has been described with respect to preferred
embodiments, it is not to be so limited as changes and modifications
can be made which are within the full intended scope of the invention
as defined by the appended claims. |