Multi-tank ion exchange water treatment system
United States Patent 1 1 Yocum Apr. 8, 1975 [54] MULTI-TANK [ON EXCHANGE WATER 3.044.626 7/l962 Rose 2lO/l03 TREATMENT SYSTEM 3,366.24! l/l968 McMorris 210/96 3,383.3l0 5/1968 Ammer 2l0/96 X [75] In e t C arl s u s ll. 3,396,845 8/1968 Bouskill 210/190 x [73] Assignee: Rock Valley Water Conditioning, I  
  Inc&#34; Rockford &#34;L Primary E.rammer-Roy Lake Asxistun! E.\&#39;aminerCraig R. Feinberg lzzl Flled: 1973 Attorney, Agent, or FirmWolfe, Hubbard, Leydig, 211 App]. No.: 387,115 &amp;  
 1521 11.5. c1. 210/96; 2l0/98; 210/190 {57] ABSTRACT [51] Int. Cl 801d 15/06 A series of ion g rs r n te in parallel in [58] Field of Sear h 210/96 93 140 142 19() a water treatment system and are electrically inter- 2 I0/l9l. I I8, 263, 102 [03, [05 424 locked against simultaneous regeneration. After an exchanger regenerates, it is held in standby status and is [56] Ref e (jir d automatically returned to service use when another UNTED STATES PATENTS exchanger begins its regeneration cycle. 1.893.933 [H933 Dotterweich 210/96 6 Claims, 5 Drawing Figures MULTI-TANK ION EXCHANGE WATER TREATMENT SYSTEM BACKGROUND OF THE INVENTION This invention relates to an ion exchange water treatment system of the type in which two or more ion ex changers are connected in parallel in a water system so as to provide relatively large treatment capacity while keeping water service available to the using system when one of the exchangers is in its regeneration cycle.  
 SUMMARY OF THE INVENTION The general aim of the present invention is to interconnect the exchangers with unique and relatively simple means for taking each exchanger out of service when the exchanger begins its regenerating cycle, for keeping the exchanger out of service and in a standby status after such exchanger completes its regenerating cycle. and for bringing the standby exchanger back into service when another exchanger begins its regenerating cycle.  
  Another object is to provide novel interconnecting means which enable construction of the exchangers as virtually identical modular units and which enable a given exchanger to be used interchangeably in treat ment systems equipped with two. three or even more exchangers.  
  The invention also resides in the provision of unique hydraulic interconnecting means which switch a newly regenerating exchanger out of service and which switch a standby exchanger into service in response to the initial flow of liquid through the drain line of the newly regenerating exchanger.  
 These and other objects and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawingsv BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic view and fluid circuit diagram of a new and improved ion exchange water treatment system embodying the novel features of the present invention.  
  FIG. 2 is a diagram of the electric control circuit for the treatment system shown in FIG. 1.  
 FIG. 3 is a schematic view of an alternative fluid circuit.  
  FIGS. 4 and 5 are views similar to FIG. 3 but showing different conditions of the fluid circuit illustrated in FIG. 3.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes of illustration, the invention is embodied in an ion exchange water treatment system having a plurality of ion exchangers II] which are connected in parallel in a water system to treat raw water flowing from a supply line I] and to deliver treated water into a service line 13 and then to at using system. Herein. three exchangers ltlut [0b and I00 are shown as being connected into the water sys tem although more than three exchangers could be used and. in many instances. only two exchangers will be employed. With two or more exchangers connected in parallel. a relatively large supply of treated water is made available to the using system and. in addition. the  
 supply of water to the using system is not interrupted when one ofthe exchangers is being regenerated. Thus. a muIti-exchanger treatment system of the type disclosed herein is capable of serving a large using system more adequately than would be the case if only a single exchanger were employed.  
  The basic exchangers 10 are of well known construc tion and each includes a tank I4 containing a bed 15 of ion exchange resin. Water flows into the top of each tank through an inlet line I6 communicating with the supply line I I, flows downwardly through the resin bed for treatment, and then flows out of the bottom of the tank through an outlet line 17 communicating with the service line I3.  
  When the exchangers 10 are regenerated to recondi tion the resin beds 15. water and regenerating chemi cals flow into and out of the tanks through riser pipes 19. the liquid which flows out each tank being carried to a drain by a drain line 20 having a flow controller 21 for restricting the rate of flow. The flow through each riser pipe is controlled by a regenerating valve 23 (FIG. 2) driven by an electrically energized valve motor 24 which. in turn. is controlled by an electrically energized timing motor 25. To simplify the drawings. the valve and the two motors have not been illustrated in detail but instead have been schematically shown as incorporated in a regeneration control unit 26 (FIGS. I and 2) located at the top of the tank [4. Various types ofconventional regeneration control units may be used and. since the basic construction. organization and operation of such units are well known. these details do not require description here. It will suffice to say that the timing motor of the unit used in the present instance is energized when a sensor 27 (FIGS. 1 and 2) detects the need for regeneration and. once energized. the tim ing motor causes the exchanger to operate through a complete regeneration cycle.  
  In the present instance the exchangers II] are interlocked to prevent more than one exchanger from regenerating at a time, the interlocking being achieved in a relatively simple and versatile manner and enabling any number of exchangers to be installed in the water system without increasing the complexity of the interlocking hardware. Such simplicity and versatility are achieved by disabling the sensor 27 of each exchanger whenever any other exchanger is regenerating so that such sensor is incapable of initiating a regeneration cycle even though regeneration may be required.  
  In one specific embodiment the control units 26 of the exchangers I0 are connected into a control circuit 30 (FIG. 2) having lines L-I and L2 connected across a source of voltage such as volts a.c. The circuit 30 includes three control branches 3] connected in parallel combination with one another across the lines L-l and L-2, there being one control unit 26 connected within and adapted to be energized by way of each control branch. The the circuit 30 further comprises three energizing paths 33 which are connected in parallel combination with one another and which include means for energizing the sensors 27. Herein, these means have been shown as being transformers 34 having their primary coils connected into the respective energizing paths 33 and adapted to convert the 120 volts a.c. source voltage into 24 volts d.c. for energizing the sensors 27.  
  The sensor 27 for each exchanger I0 is attached to the riser pipe 19 (FIG. 1) and has been illustrated in a schematic manner since the sensor which is used herein is well known and since various types of sensors may be used. Basically. the sensor which is disclosed detects the conductivity of the resin bed and produces an electrical signal as an incident to the conductivity reaching a certain level when the bed requires regenerating. The sensor is adapted to be energized by way of a sensing circuit 35 (FIG. 2) and has been illustrated schematically as forming part of a Wheatstone bridge 36 which is normally in balance but which reaches a critical level of imbalance when the conductivity of the resin bed changes sufficiently to dictate the need for regeneration. To energize the sensors 27. the secondary coils of the transformers 34 are included within the respective sensing circuits 35 and are connected to the input terminals of the respective bridge 36. The output terminals of each bridge 36 are connected across a responding means in the form of a normally de-energized relay 37 whose normally open contacts 39 7 are located in the respective control branch 31 of the control circuit 30.  
  Let it be assumed that none of the exchangers 10 is in a regeneration cycle and that the sensor 27 of one exchanger (for example. the exchanger 10a) detects that such exchanger requires regeneration. At such time. the bridge 36a reaches a critical level of imbalance and supplies the relay 37a with current sufficiently high to energize the relay. Energization of the relay causes closing of the contacts 390 in the control branch 31a so as to energize the timing motor of the control unit 26a. As the timing motor starts up. a cam [not shown) driven by the motor closes a normally open switch 40a which seals around the relay contacts 39a and maintains an energizing circuit to the motor when the relay 37a is subsequently de-energized and the relay contacts re-opened. As will be explained subsequently. the relay 37a is de-energized shortly after the initiation of a regenerating cycle.  
  After being energized. the timing motor 25a acts through conventional mechanism and circuitry housed within the control unit 26a and illustrated schematically at 4111 (FIG. 2) to cause energization of the valve motor 24a at appropriate intervals. The valve motor drives the regenerating valve 230 to different positions to cause the exchanger 10a to operate through a full re generation cycle. When the regeneration cycle is completed and the valve 23a is returned to service position. the timing motor 25:: causes opening of the switch 40a to de-energize the control branch 310.  
  To advantage the exchangers 10 are interlocked against simultaneous regeneration by three normally closed interlocking switches 43a. 43b and 43c connected with one another in the control circuit 30 in a series combination which. in turn. is connected in series with the parallel combination of energizing paths 33. If any one of the interlocking switches 43 is opened. current flow to all of the energizing paths 33 is interrupted and thus the transformers 34 and the sensing circuits 35 are de-energized. Under these conditions. any exchanger which is not already regenerating cannot begin a regeneration cycle because. even ifthe conductivity of the resin bed 15 of such exchanger reaches the regeneration level. the respective sensing circuit 35 is de-energized and thus the relay 37 cannot be ener gized to close the contacts 39 in the respective control branch 31.  
  Again. let it be assumed that none of the exchangers 10 is in a regeneration cycle and that the sensor 27 of one exchanger (the exchanger 10a) detects that such exchanger requires regeneration. When the previously described regeneration cycle is initiated and the valve motor 240 is energized. a cam 44a (FIG. 2) driven by the valve motor causes the interlocking switch 43a to open. As a result. all of the transformers 34 and sensing circuits 35 are de-energized since current flow to the energizing paths 33 is interrupted. Thus. the other two exchangers 10b and 10c cannot begin a regeneration cycle. Even though the relay 37a is de-energized when the switch 43a is opened. the exchanger 10a continues with its regeneration cycle by virtue of the circuit maintained to the control branch 310 by the sealing switch 40a.  
  The interlocking switch 430 is held open during the entire regenerating cycle of the exchanger 10a and thus the exchangers 10b and are prevented from regenerating. When the exchanger 10a completes its regeneration cycle. the cam 44a closes the interlocking switch 430 to re-establish current flow to all of the energizing paths 33 so that any exchanger which either then or subsequently requires regeneration is capable of beginning its regenerating cycle. It will be appreciated that the interlocking switches 43b and 430 are&#39; opened and closed in the same fashion as the interlock ing switch 43a and thus the exchangers 10a and H]:- are prevented from regenerating when the exchanger 10b is regenerating and the exchangers 10a and [0b are prevented from regenerating when the exchanger 100 is regenerating.  
  From the foregoing, it will be apparent that the energizing paths 33 for the sensor circuits 35 are connected in parallel combination with one another and are separated or isolated from the parallel combination of the control branches 31. The interlocking switches 43 for controlling the energizing paths 33 are connected in a series combination which is connected in series with the parallel combination of energizing paths. With this arrangement. the circuitry is relatively simple and is virtually identical for each exchanger 10 so as to enable manufacture of the exchangers as substantially identical modular units. ln addition. any number of exchangers may be added to the water treatment system and interlocked with the other exchangers without increasing the complexity of the wiring harnesses between the exchangers. For example. it will be seen in FIG. 2 that the exchanger 10a is connected to the exchanger 10b by a four-wire harness not including a ground wire) and by ajack and plug unit 45a (the latter being shown in four places in the drawing but collectively being one unit). The exchanger 10b. in turn. is connected to the exchanger l0c by a similar four-wire harness and jack and plug unit 45b. Any number of exchangers may be connected into the system with similar four-wire harnesses and without need of providing additional wiring within the harnesses. The lead exchanger 10a. of course. includes an additional harness leading to the ac. voltage source. and the jack 451&#39; of the harness of the final exchanger 100 is suitably jumpered as indicated at 46 in order to complete the control circuit 30.  
  According to the present invention. the exchangers 10 are hydraulically interconnected in a novel manner so that each exchanger which completes its regenerating cycle is not immediately returned to service use but instead is held in a reserve or standby status until such time as another exchanger begins its regenerating cy cle. In this way, a freshly regenerated exchanger is made available to the using system whenever another exchanger begins regenerating and thus a continuous supply of treated water is insured.  
  In order to prevent a given exchanger from returning to service use after it completes its regenerating cycle. the flow system through the exchanger is closed off during the regenerating cycle and is kept closed until another exchanger beings regeneration. To close off the flow system. shutoff valves and 51 (FIG. 1) are connected into the inlet and outlet lines 16 and 17 of each exchanger and are adapted to be moved between opened and closed positions by fluid-operated actuators 53 and 54. In this instance. cach valve actuator comprises a walled chamber 55 which is divided into two compartments by a flexible diaphragm 56. the latter being springbiased in an upward direction and being connected to the shut-off valve. When fluid under pres sure is admitted into the upper side of the chamber 55 of the upper actuator 53 through a line 57 the respective diaphragm is flexed downwardly to close off the valve 50 in the inlet line 16. At the same time. pressure is transmitted to the upper side of the chamber of the lower actuator 54 through a line 59 and serves to close off the valve in the outlet line 17. When the pressure is dumped from the line 57. both valves are automatically returned to their open positions by virtue of the upward spring bias applied to the diaphragms 56.  
  To control the flow of pressure fluid to and from the valve actuators 53 and 54. a pilot valve 60 is associated with each exchanger 10 and includes a valve spool 61 slidable within a housing 63. When the valve spool is shifted to the right from the position shown in FIG. 1, a land 64 is located so as to enable the line 57 to communicate with a line 65 connected to the supply line 11. Accordingly, water under pressure is directed to the actuators 53 and 54 to close the shut-off valves 50 and 51. When the spool 61 is returned to the left, the line 57 communicates with a drain line 66 and thus the water is dumped from the actuators to allow the shutoff valves to return to their open positions.  
  Normally. the valve spool 61 of each pilot valve 60 is located to the left in a service position as shown in FIG. 1. When the associated exchanger 10 begins its regenerating cycle. the valve spool is shifted to the right to a standby position to close off the flow system of the exchanger and thus take the exchanger out of service use. To shift the valve spool from its service position to its standby position. a line 67 advantageously communicates with the exchanger drain line 20 at a point upstream from the flow controller 2] and also communicates with a chamber 69 located at the left end of the valve housing 63, there being a piston 70 slidable in the chamber and connected to the valve spool 61. When the exchanger begins its regenerating cycle. liquid flows through the drain line 20 and. because of the restriction created by the flow controller 21, a pressure pulse is created in the line 67 and is transmitted to the piston 70 to shift the valve spool 61 to the right to its standby position. Thus, the shut-off valves 50 and 51 are closed automatically as an incident to the exchanger producing a pressure pulse in its drain line 20 at the beginning of its regenerating cycle.  
  The spool 61 of a given pilot valve 60 remains in its standby position even after the associated exchanger 10 completes its regenerating cycle and is returned to service position only when another exchanger begins regeneration. To return the spool to its service position. a pressure pulse is transmitted to a piston connected to the right end of the valve spool and slidable within a chamber 76 at the right end of the valve housing 63. The chamber 76 communicates with a header 77 which. in turn. communicates with the drain lines 20 of the other two exchangers by way of lines 79 and 80. Thus. when either of the other two exchangers 10 begins a regeneration cycle, a pressure pulse from one of the drain lines 20 is transmitted through the lines 79 or 80 to the piston 75 of the valve spool 61 in standby position. The spool thus is shifted to the left to its service position by the pressure pulse so as to cause opening of the shut-off valves 50 and 51 of the associated ex changer and thereby switch the exchanger from standby to service.  
  From the foregoing. it will be apparent that two functions are performed by the pressure pulse produced in the drain line 20 of any given exchanger 10 when that exchanger begins its regeneration cycle. That is. the pressure pulse shifts the valve spool 61 of the regenerating exchanger into its standby position so that the ex changer will not return to service when its regenerating cycle is completed. Secondly. the pressure pulse simultaneously acts on the valve spool of the exchanger which has previously been on standby and shifts that valve spool to its service position so as to switch the as sociated exchanger from standby to service. In this way. a freshly regenerated exchanger is brought into service each time another exchanger begins its regeneration cycle. Since the exchangers are electrically interlocked against simultaneous regeneration. it is not possible for a pressure pulse to exist in more than one drain line 20 at any given time. Accordingly. when pressure is applied to one of the pistons 70 or 76 of any valve spool. there is no back pressure against the other piston and thus the spool may shift freely. Moreover. once shifted. the valve spool remains in a stable position until it is shifted reversely by a pressure pulse originating from another exchanger.  
  An alternative pilot valve arrangement is shown in FIGS. 3 to 5 and is advantageous in that it reduces the number of pilot valves required and also simplifies the piping so as to enable additional exchangers to be easily added to the system without need of directly connecting the drain line of each exchanger to the pilot valve of every other exchanger. When three exchangers 10 are connected in the system, two pilot valves and 91 are used and the valves include spools 93 and 94, re spectively, disposed end-to-end and each adapted to move between left and right positions.  
  As shown. the line 67a leads to the left end of the spool 93, the line 67c leads to the right end of the spool 94, and the line 67b leads to a pipe 95 which extends between the right end of the spool 93 and the left end of the spool 94. The supply line 11 and the line 57a lead to the valve 90 while the lines 57b and 57c lead to the valve 91. The valve 90 communicates directly with a drain line 96 while the valve 91 communicates with the drain line by way of lines 97 and 98. Finally, the valve 90 communicates with the valve 91 via lines 99 and FIG. 3 shows the positions of the valve spools 93 and 94 when the exchanger 10a is regenerating and the exchangers 10b and 10c are in service. When the exchanger 100 begins regenerating, a pressure pulse is produced in the line 67a to shift the spool 93 to the right to the position shown in FIG. 3. As a result. water under pressure is directed from the supply line 11 to the line 57a to close off the flow system of the exchanger 10a.  
  Now assume that the exchanger 10a completes re generation and the exchanger 10b begins regenerating. At this time. a pressure pulse is produced in the line 67b and passes through the pipe 95 to shift the spool 93 to the left to the position shown in FIG. 4. As a resalt. the line 5711 is vented to the drain line 96 to cause opening of the llow system of the exchanger I01! so as to switch that exchanger from standby to service. At the same time. water under pressure is directed from the supply line ll to the line 5711 via the line 99 and thus the flow system ofthe exchanger 10!) is closed off.  
  If it now be assumed that the exchanger lllb completes regeneration and the exchanger 10c begins re generation. a pressure pulse is produced in the line 67c to shift the spool 94 to the left as shown in FIG. 5. As an incident thereto. the line 57b is vented to the drain line 96 by way of the line 97 and thus the flow system of the exchanger 10/1 is opened up to switch that exchanger from standby to service. In addition. water under pressure is directed from the supply line 1] to the line 571 by way of the line 99 and thus the flow system of the exchanger 100 is closed off.  
  if the exchanger Illa is the exchanger which next regenerates. the spool 93 is shifted to the right and the line 570 is vented to the drain line 96 so as to return the exchanger 101 to service use. If the exchanger 10b is the exchanger which next regenerates. the pressure pulse produced in the line 67b and the pipe 95 shifts the spool 94 to the right so that the line 57c is vented to the drain line 96 by way of the line 98.  
  Ifthe exchangers l regenerate in certain unusual sequences. the pressure pulses alone are not effective to shift the valve spools 93 and 94 to the proper positions To overcome this disability. a rod 101 is loosely telescoped into the pipe 95. The length of the rod is equal to the distance between adjacent ends of the spools when the spool 93 is left and the spool 94 is right. minus the distance through which a spool shifts in moving between its positions.  
  Now assume. for example. that the exchanger a is in standby (the spool 93 thus being to the right] and the exchanger [0c begins regenerating. The pressure pulse produced in the line 67c is effective to move the spool 94 from right to left but, without the rod 101. the spool 93 would remain to the right. Water under pressure then would continue to be directed from the supply line 11 to the line 57a and none would be directed to the line 570. By virtue of the intermediate rod I01, how ever. the spool 94 mechanically shifts the spool 93 to the left. the left end of the spool 94 engaging and pushing the rod which. in turn. engages and pushes the spool 93. The spools thus are positioned as shown in FIG. 3 to switch the exchanger 10a to service and to place the exchanger 10c in standby. The rod I01 thus causes the spool 93 to shift left [if that spool is right) when the spool 94 shifts left and yet leaves the spool 94 free to shift right without changing the position of the spool 93. With this arrangement. the exchangers will always be properly placed into and taken out of standby regardless of the sequence of regeneration.  
  From the foregoing. it will be apparent that the valving arrangement shown in FIGS. 3 to 5 enables three exchangers to be controlled with only two pilot valves and 91. I have found that as many as twelve exchangers can be incorporated in the system and. for each exchanger that is added. one additional pilot valve is used. Thus, the number of pilot valves is one less than the number of exchangers. In addition to reducing the number of pilot valves. the valving arrangement shown in FIGS. 3 to 5 simplifies the piping between the exchangers and enables additional exchangers to be easily incorporated into the system.  
 I claim:  
  I. An ion exchange water treatment system comprising a plurality of ion exchangers connected in parallel in a water system. each of said exchangers having a flow system by which water flows through the exchanger when the latter is in service use. valve means associated with the flow system of each exchanger and movable between open and closed positions to open and close such flow system. means associated with each exchanger for intermittently causing the exchanger to operate through a regenerating cycle, each exchanger including a drain system through which liquid flows during said regenerating cycle. and means associated with each exchanger and operable to cause closing of the valve means of such exchanger and to cause opening of the closed valve means of any other exchanger in response to the flow of liquid through the drain system of such exchanger.  
  2. An ion exchange water treatment system comprising a plurality of ion exchangers connected in parallel in a water system, each of said exchangers having a flow system by which water flows through the ex changer when the latter is in service use, at least one valve associated with the flow system of each exchanger and movable between open and closed positions to open and close such flow system. a fluid operated actuator connected to each valve for moving the latter between its positions as fluid is delivered to and dumped from the actuator. a pilot valve associated with each actuator and movable between service and standby positions. said pilot valve delivering fluid to said actuator when in one of said positions and dumping fluid from the actuator when in the other of said positions, means associated with each exchanger for intermittently causing the exchanger to operate through a regenerating cycle. each exchanger including a drain system through which liquid flows during said regenerating cycle, and means connecting the drain system of each exchanger with the pilot valve of such exchanger and with the pilot valve of every other exchanger to cause the respective pilot valve to move to standby positions and to cause any other pilot valve in standby po sition to move to service position in response to the flow of liquid through the drain system of such exchanger.  
  3. An ion exchange water treatment system as defined in claim 2 in which at least three ion exchangers are connected in parallel in said water system.  
  4. An ion exchange water treatment system comprising a plurality of ion exchangers connected in parallel in a water system. each of said exchangers having a flow system by which water flows through the exchanger when the latter is in service use. at least one valve associated with the flow system of each exchanger and movable between open and closed positions to open and close such flow system. a fluid operated actuator connected to each valve for moving the latter between its positions as fluid is delivered to and dumped from the actuator. a plurality of pilot valves associated with said exchangers and controlling the flow of fluid to and from said actuators, means associated with each exchanger for intermittently causing the exchanger to operate through a regenerating cycle. each exchanger including a drain system through which liquid flows during said regenerating cycle. and means connecting the drain systems of said exchangers with said pilot valves to cause the pilot valves to effect closing of the flow system of any regenerating exchanger and opening of the closed flow system of any other exchanger in response to the flow of liquid through the drain system of said regenerating exchanger.  
 LII  
  5. An ion exchange water treatment system as defined in claim 4 in which the number of pilot valves is one less than the number of exchangers.  
  6. An ion exchange water treatment system as defined in claim 5 which includes at least two pilot valves disposed end-to-end. each of said valves including a spool movable between first and second positions. and means mechanically interconnecting said spools to shift one of the spools from its first position to its second position when the other spool is shifted from its first position to its second position while leaving said other spool free to shift back to its first position without changing the position of said one spool.