Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
  • B01J49/80—Automatic regeneration
  • B01J49/85—Controlling or regulating devices therefor

Definitions

• the present invention relates to a novel method and apparatus for the treatment of liquid utilizing two or more treatment beds. More particularly, it relates to a treatment method and apparatus wherein two or more treatment tanks, each containing a treatment bed are connected in a parallel arrangement for treating a liquid. Even more particularly, this invention relates to the use of such a method and apparatus in an automatic water softening system.
• a liquid such as water prior to its use.
• Such treatments of water include softening to remove hardness and also filtering to remove solid suspended particles.
• soften hard water for many industrial, commercial and household uses.
• the liquid to be treated customarily flows through a pressurized tank containing a regeneratable treatment material. It is necessary to regenerate the treatment material, wherein its capacity to treat the liquid is lost.
• ion exchange resin particles acquire hardness inducing ions from hard raw water which is treated in exchange for soft ions. That is, ions which do not induce hardness to the water.
• the resin particles are regenerated by exposing bathing them in a brine solution, i.e., an aqueous solution of sodium chloride or potassium chloride or the like during a regeneration cycle.
• a brine solution i.e., an aqueous solution of sodium chloride or potassium chloride or the like
• the ion exchange process which takes place during the regeneration of the ion exchange material, is accomplished in a resin tank of softeners of well-known construction.
• the regeneration cycle is conducted during the early morning hours when water is normally not used.
• the most efficient regeneration of ion exchange material occurs when it is not regenerated until it is essentially depleted. It is further desirable to provide a water treatment or water softening system wherein the treated or softened water may be continuously provided, i.e., the supply is not interrupted by the need to regenerate the treatment bed.
• a water treatment or water softening system which employs at least two tanks containing treatment beds.
• the tanks are connected in parallel such that the untreated liquid flows through the treatment bed in either of the tanks, to emerge as a treated liquid. If more than two treatment tanks are utilized, there are as many parallel flow paths as there are treatment tanks.
• a flow meter is provided to measure the amount of liquid treated, such that by knowing the hardness of the water in the case of a softener, the amount of treatment capacity used in the treatment of the water can be determined.
• Electronic means are provided for recording the amount of treatment capacity of each of the treatment beds which has been utilized since it was last regenerated.
• the predetermined minimum amount of remaining capacity is equal to the full or total capacity of one of the treatment beds divided by the number of treatment beds connected in parallel.
• the recording means for that treatment bed is reset to again record the depletion of its treatment ability.
• FIG. 1 is a schematic representation of the liquid flow paths for two treatment tanks connected in accordance with this invention.
• FIG. 2 is a schematic diagram of an electrical control circuit for controlling the regeneration of two treatment tanks in accordance with this invention.
• FIGS. 3A through 3F are representations of manner in which a two tank system is regenerated in accordance with this invention.
• FIG. 4 is a flow diagram for a two resin tank softening system, setting forth the regeneration decisions in accordance with this invention.
• FIGS. 5A through 5E are representations of manner in which a three tank system is regenerated in accordance with this invention.
• FIG. 1 a schematic diagram of the liquid flow paths for a two tank system in accordance with this invention is shown in FIG. 1.
• a pair of tanks containing ion exchange resin particles are represented 10 and 12.
• a supply of raw water is connected to supply pipe 14 which is connected to the inlets 16 and 18 of the tanks 10 and 12 respectively through a shut-off valve 20, pipe 22, and tee connection 24.
• the outlets for the discharge of the treated or softened water 26 and 28 of tanks 10 and 12 respectively are connected together through another tee connection 30, a flow measuring device 32, a pipe 34, and a shut-off valve 36 to a treated water outlet pipe 38.
• bypass valve 40 is provided.
• the bypass valve 40 should only be opened when valves 20 and 36 are closed.
• the measuring device or means 32 may be in the form of a turbine-type meter which provides an electrical output indicative of the quantity of flow of processed or softened water through outlet pipe 38.
• control circuit 40 receives an electrical signal output from the flow measuring device 32 through leads 42, so as to enable recording means within the control circuit 40 to maintain a record or register of the use of the capacity of each of the tanks 10 and 12.
• the microprocessor in accordance with an algorithm recorded therein, utilizes the recorded use of the capacity of each of the tanks 10 and 12 to develop control signals which control the valve motors 44 and 46 which control the regeneration cycles of each of the tanks 10 and 12 respectively.
• the various flow cycles necessary for regenerating a water softener resin bed using a brine solution are well known in the art and are not further described herein.
• the microprocessor 40 is connected to valve motor 44 by the leads 48 and 50, and to the valve motor 46 by the electrical leads 52 and 54.
• the outlet 26 and 28 from the tanks 10 and 12, as well as the flow measuring device 32 and the outlet pipe 38 are also shown in FIG. 2. Referring to FIGS. 3A through 3F, the manner in which a two tank system is regenerated in accordance with this invention will be described.
• the two tanks of the system are shown as tanks 1 and 2.
• the remaining softening capacity of each of the tank is represented by the darkened area of the tank.
• both resin tanks be placed in service at full or 100% capacity, as represented by the fully darkened tanks in FIG. 3A.
• the capacity of both tanks is equally depleted. The depletion of the tanks will continue until both of the tanks are depleted to a predetermined minimum amount of remaining capacity, which in the case of a two tank system is preferably 50% of the tanks full capacity.
• tank 1 is taken out of service and regenerated when it is exhausted to 50% of its total capacity.
• Tank 2 remains in service to provide softened water, such that its remaining capacity drops below 50% if softened water is used while tank 1 is being regenerated.
• tank number 1 has been regenerated to full or 100% capacity, while the remaining capacity of tank 2 has continued to drop during the regeneration of tank 1, due to the use of softened water.
• Tank 1 will return to the service position and both tanks will remain in service until tank 2 is exhausted to a predetermined lower limit, which is normal close to full exhaustion, and is shown as such in FIG.3D.
• Tank 1 remains in service to handle all the softening requirements until the regeneration of tank 2 is finished.
• FIG.3E the remaining capacity of tank 1 will have continued to drop as tank number 2 is regenerated and restored to full or 100% of capacity. Both tanks will be on line again until tank number 1 has been completely exhausted.
• tank 1 has become completely exhausted, such that it will be regenerated and tank 2 will handle all of the softening requirements while it is being regenerated. Thereafter, the cyclic regeneration of the tanks will continue as from the condition shown in FIG.3C.
• the fundamental decision when to initiate a regeneration of one of the two resin tanks is: Is the capacity used recorded by the softener's electronic control equal to the set capacity in the control? Or in other terminology, is the capacity remaining in a resin tank at 50% or 0% (completely depleted) . If one of the two conditions is true a regeneration will be initiated immediately.
• the 50% remaining capacity trip point is used to prevent hard water bleed when one tank is on line and the other tank is regenerating. It is also used to insure sufficient softening capacity remains in the tank remaining in service.
• the softener must be more carefully sized to the installation because sufficient capacity must remain in the tank left in service while the other tank regenerates.
• the salt or brine dosage used to regenerate a tank in accordance with the system of this invention is always that necessary to fully restore and essentially depleted tank.
• the advantage of a twin resin tank softener configuration is that a continual source of soft water is available. As the softener softens, water capacity in the two tanks depletes. When the softening capacity has been depleted to a preset level or predetermined minimum amount, one resin tank will regenerate and the other tank will remain on line softening water. The capacity in the resin tank remaining on line must be sufficient to provide soft water during the regeneration. Every time a regeneration occurs, the regeneration will use preselected salt and water efficient settings, for completely regenerating the tank.
• the Twin Tank Softener is designed to provide the highest possible salt efficiency and the minimum possible water usage for regeneration. Because two resin tanks are used, the regeneration of one tank can occur at any time of day because there is always capacity available in the opposite tank to provide soft water. Under normal operating conditions, both resin tanks operate simultaneously to provide soft water, each tank processing one half of the water used. The controller directs the valve operation such that the resin tanks are operated in a out-of-phase regeneration sequence so that at least one tank always has water softening capacity available.
• FIG. 4 This flow diagram sets forth the regeneration decision made in accordance with this invention.
• the present invention not only contemplates two tank systems but also multi-tank systems.
• FIGS. 5A through 5E the manner in which a three tank system is regenerated in accordance with this invention will be described.
• the three tanks of the system are shown as tanks 1, 2 and 3.
• the remaining softening capacity of each of the tank is represented by the cross-hatched area of the tank. While the initial start up conditions could be different, it is preferred that all of the resin tanks be placed in service at full or 100% capacity, as represented by the fully cross- hatched tanks in FIG. 5A.
• tank 1 is taken out of service and regenerated when it is exhausted to 66.7% of its total capacity.
• Tanks 2 and 3 remain in service to provide softened water, such that their remaining capacities drop below 66.7% if softened water is used while tank 1 is being regenerated.
• tank number 1 has been regenerated to full or 100% capacity, while the remaining capacities of tanks 2 and 3 continued to drop during the regeneration of tank 1, due to the use of softened water.
• Tank 1 will return to the service position and all three tanks will remain in service until tank 2 or tank three or both are exhausted to a predetermined lower limit, which is normal close to full exhaustion.
• tank 3 is shown full regenerated in FIG.5D, while the capacities of tanks 1 and 3 continue to be reduced due to the use of softened water while tank 2 is being regenerated.
• the capacity of tank 3 having been completely exhausted, as shown in FIG.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Treatment Of Water By Ion Exchange (AREA)

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• 1993
  • 1993-12-14 CA CA002154443A patent/CA2154443A1/en not_active Abandoned
  • 1993-12-14 WO PCT/US1993/012201 patent/WO1994013379A1/en not_active Application Discontinuation
  • 1993-12-14 EP EP94903655A patent/EP0673275A4/de not_active Withdrawn

Non-Patent Citations (2)

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