Liquid purification or separation – Flow – fluid pressure or material level – responsive – Filter cleaning
Reexamination Certificate
1999-03-29
2001-04-10
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
Flow, fluid pressure or material level, responsive
Filter cleaning
C210S143000, C210S142000, C210S190000, C210S269000, C137S624180
Reexamination Certificate
active
06214214
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to fluid treatment and in particular to an improved control system and control device for controlling a fluid treatment apparatus.
BACKGROUND ART
U.S. Pat. No. 4,298,025, which is owned by the present assignee, discloses a control valve for use in water softeners having two resin tanks. One of the resin tanks is normally on-line while the other tank is regenerated and placed in a standby condition until the first tank requires regeneration. The disclosed control valve controls which of the tanks is on-line and controls the regeneration sequence of an exhausted tank.
The quantity of water treated by a given tank, is monitored by a mechanism that includes a water usage turbine driven by water entering the on-line resin tank. When a predetermined quantity of water is treated, which produces to a predetermined number of revolutions in the turbine, a regeneration sequence is initiated which places the standby tank on-line and isolates the exhausted tank.
A second turbine, operatively connected to a regeneration sequence control element (in the form of a disk) is rotated by a stream of water that is activated at the beginning of the regeneration cycle. The stream of water physically drives the regeneration control disk (via the turbine and associated drive train) through its sequence. With the disclosed arrangement, the frequency of regeneration of the water softener system is determined by the usage turbine which directly measures the quantity of fluid treated by a given tank.
In Pat. No. 4,427,549 which is also owned by the present assignee, a deionization method and apparatus is disclosed. The disclosed apparatus includes a control valve similar to the control valve disclosed in U.S. Pat. No. 4,298,025 in that it includes a usage turbine for monitoring the amount of source water treated by a given tank and a regeneration control turbine for driving a control element through a regeneration sequence.
In the control valves disclosed in the above-identified patents, the last step in the regeneration sequence is a water rinse that is performed in the counterflow direction. It is known that a fast rinse in the service direction or “downflow” rinse provides certain advantages over a rinse in the counterflow direction. For example, a downflow fast rinse tends to pack the media bed making the operation of the bed more effective upon initial start-up. Attempts have been made to provide a downflow fast rinse in the type of control valve disclosed in the above-identified patents, but these attempts have resulted in undue complexity in the valve, and the need for creating additional fluid signals in order to provide the necessary rinse function.
It has also been found desirable to improve the overall efficiency of the type of valve disclosed in the above-identified patents, so that the amount of water consumed during regeneration is reduced.
DISCLOSURE OF INVENTION
The present invention provides a new and improved control valve for controlling a fluid treatment apparatus such as a deionization system or a water softener. In the illustrated embodiment, the improved control valve is used to control a fluid treatment system having a pair of resin tanks, one of which is on-line, while the other is regenerated and held in a standby condition. The disclosed control valve, although similar to the control valves described in U.S. Pat. Nos. 4,298,025 and 4,427,549, which are hereby incorporated by reference, includes several improvements which enhance the overall operation of a fluid treatment system that utilizes the control valve.
According to the invention, a water treatment apparatus is disclosed including at least one treatment tank containing a treatment material The tank defines a fluid flow path through which water to be treated is passed. The treatment tank may form part of a water softener, deionization unit or a mechanical filter. A control unit similar in construction to the control valve illustrated in U.S. Pat. Nos. 3,891,552 and 4,298,025 controls the communication of water to be treated (or a water source) with a tank inlet and controls the communication of treated water from a tank outlet and a conduit or system outlet. In the illustrated embodiment, the control unit also has a regeneration controller that controls the regeneration of the tank when needed.
In accordance with the invention, a downflow rinse is provided during regeneration which communicates rinse water to the tank and passes it through the tank in a service direction and discharges the rinse water to an ambient drain. To achieve this feature, the control unit includes a purge valve for communicating the outlet of the tank with an ambient drain. According to the invention, the purge valve communicates the outlet of the tank with an ambient drain when an outlet valve associated with the tank is closed and an associated inlet valve is closed. The inlet valve controls the communication of the source water with the inlet of the tank. In the illustrated embodiment, the purge valve does not require a separate signal from the regeneration controller to effect the required communication of the tank outlet with the ambient drain. It utilizes existing signals that are used to close the associated outlet valve and open the associated inlet valve.
In accordance with a more preferred embodiment of the invention, the apparatus includes a second tank and the control unit is operative to control which of the tanks is on-line and which of the tanks is regenerated and then kept off-line until the on-line tank requires regeneration. Both tanks in this more preferred embodiment, however, are rinsed in the service direction by the regeneration controller, during a regeneration cycle. In the more preferred embodiment, the controller includes separate purge valves for each tank, each of the purge valves being controlled by a combination of signals sent to the corresponding tank inlet and tank outlet valves. In the preferred and illustrated embodiment, the signals comprise fluid signals which apply pressures to valve operating pistons forming part of the respective tank inlet and outlet valves.
According to another feature of the invention, the regeneration controller includes a regeneration turbine which is driven by fluid emitted from a regeneration control nozzle. The disclosed turbine is an improvement of the regeneration control turbine shown and discussed in the above-identified patents. The improved turbine includes a plurality of vanes extending from a hub. Side edges of the turbine blades are captured between a pair of disc-like structures so that a plurality of enclosed cavities are provided. These enclosed cavities receive fluid emitted by the regeneration control nozzle, which in turn applies forces to the turbine causing its rotation. Because the cavities are enclosed, the fluid emitted by the nozzle can only escape through the openings through which the fluid entered. In the past, turbine blades of the regeneration control turbine extended openly and were not confined. The disclosed turbine construction substantially improves the efficiency of the regeneration control mechanism thereby reducing the amount of driving fluid needed to sequence the controller through a regeneration cycle.
A fuller understanding will be obtained and additional features of the invention will become apparent in reading the following detailed description made in connection with the accompanying drawings.
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Halemba Peter
Hansen Christopher L.
Park Stuart
Cecil Terry K.
Drodge Joseph W.
Kinetico Incorporated
Watts, Hoffman, Fisher & Heinke Co.
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