# US 7,744,765 B2 · Water treatment system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,765 B2 - Document ID: US7744765B2 - Status: Granted - Kind: B2 - Application number: 12/087,997 - Filed: 2006-01-23 - Published: 2009-01-08 - Granted: 2010-06-29 - Earliest claimed: 2006-01-23 - Assignees: Firstwater Controls DA - Inventors: Jørn-Rudi Bjerkan; Morten Fredriksen - Web page: https://patentgrep.com/patent/US7744765B2 ## CPC - E04H 4/1281: {Devices for distributing chemical products in the water of swimming pools} - C02F 1/008: {Control or steering systems not provided for elsewhere in subclass C02F} - C02F 1/68: by addition of specified substances, e.g. trace elements, for ameliorating potable water (medicinal water A61K) - C02F 1/02: by heating (methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D) - C02F 2103/42: from bathing facilities, e.g. swimming pools - C02F 2209/006: comprising a software program or a logic diagram - C02F 2209/03: Pressure - C02F 2301/046: Recirculation with an external loop - C02F 2303/04: Disinfection - E04H: BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL (foundations E02D) - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) ## Abstract A system, a device and a method for maintaining water quality in a pool or similar water container for use by people which is characterized in that a pressure sensor is arranged to sense the pressure variations inside a main water container 1 and to provide a pressure variation signal to a control and processing unit 3. The control and processing unit is connected with a dispensing module and is adapted to generate and transfer control signals to said dispensing modules. The control signal depends on the detected pressure variation signal. The system for water treatment comprises also a water treatment circulation loop 3A-D at least one controllable chemical dispensing module 8A-D, 9A-D. The circulation loop is adapted to pump water from the main water container 1, around the circulation loop 3A-D, and back into the main water container 1 via the dispensing module for dispensing a chemical treatment agent. ## Claims ### Claim 1 A water treatment system comprising: a main water container, a water treatment circulation loop, at least one controllable chemical dispensing module, said circulation loop being adapted to pump water from the main water container, around the circulation loop, and back into the main water container, wherein a pressure sensor is arranged to sense the pressure variations inside the main water container and to provide a pressure variation signal to a control and processing unit, said control and processing unit being connected to said dispensing modules and being adapted to generate and transfer control signals to said dispensing modules via a control signal line, said control signal depending on said pressure variation signal. ### Claim 2 (depends on 1) The water treatment system according to claim 1, wherein the processing unit is programmable so as to be able to provide a value representing the current usage of the main water container. ### Claim 3 (depends on 1) The water treatment system according to claim 1, wherein the dispensing modules comprise a number of chemical vessels, each chemical vessel being coupled via a peristaltic pump to a mixing chamber being a part of said circulation loop whereby said control signals determine the amount of chemical to inject into the circulating water. ### Claim 4 (depends on 1) The water treatment system according to claim 1, wherein the control and processing unit is adapted to check the usage of the main water container, whereby the control signals being generated and sent to peristaltic pumps depend on the outcome of said usage check. ### Claim 5 (depends on 1) The water treatment system according to claim 1, wherein the duty cycle of the chemical dispensing function is set by the control and processing unit on the basis of input signals of a pressure sensor, said pressure sensor being located so as to sense the pressure variations in said main water container caused by people using/entering the main water container. ### Claim 6 (depends on 1) The water treatment system according to claim 1, wherein said pressure sensor is coupled with said main water container via a hose or pipe entering said main water container via a housing of a water filter. ### Claim 7 (depends on 1) The water treatment system according to claim 1, wherein said pressure sensor is coupled with said main water container via a hose or pipe entering said main water container via a pressure nipple arranged in a hole in a wall of said main water container. ### Claim 8 (depends on 1) The water treatment system according to claim 1, wherein said pressure sensor is mounted in a flange arranged in a hole in a wall of said main water container. ### Claim 9 (depends on 1) The water treatment system according to claim 1, wherein said at least one controllable chemical dispensing module is arranged in thermal contact with a part of the water treatment circulation loop, in order that heat energy of the water is used to prevent the at least one controllable chemical dispensing module from freezing. ### Claim 10 (depends on 1) The water treatment system according to claim 1, wherein the main water container is a spa. ### Claim 11 A dispensing device for dispensing a controlled amount of a chemical into a water container, such as e.g. a pool or spa, comprising: a pressure sensing device arranged to sense pressure variations in water contained by said container, a dispensing device coupled to said water container for dispensing a controlled amount of a water treatment chemical into said water, a processing unit having an input connected to said pressure sensing device, said processing unit being adapted for generating an output signal to said dispensing device, where said signal depends on the said pressure input signal, so that the dispensed amount of chemical is made to depend on the sensed pressure variations. ### Claim 12 (depends on 11) The dispensing device according to claim 11, comprising a signal filter arranged to filter the signal from the pressure sensing device. ### Claim 13 (depends on 12) The dispensing device according to claim 12, wherein the signal filter is adapted to attenuate the high frequency components of the pressure signal while passing low frequency components. ### Claim 14 (depends on 12) The dispensing device according to claim 12, wherein the signal filter comprises a low-pass filter with a cut-off frequency of about 5 Hz. ### Claim 15 (depends on 12) The dispensing device according to claim 12, wherein the signal filter is an electronic circuit having a filtering function and which is integrated in the pressure sensor. ### Claim 16 (depends on 12) The dispensing device according to claim 12, wherein the signal filter is a computer program module incorporating a filtering function and which is a part of the computer program running in the main programmable processing module. ### Claim 17 A method of maintaining the quality of water in a container, the method comprising the steps of detecting pressure variations in the water in the container due to the activity of people present in the container by the use of a pressure sensing device, generating a pressure variation dependent output signal using a processing unit taking as an input an output of said pressure sensing device, transferring said output signal to a controllable dispensing device adapted and arranged for dispensing a chemical into said water in dependence on said generated signal, whereby the amount of dispensed chemical is made to depend on the activity of people using the container. ### Claim 18 (depends on 17) The method according to claim 17, wherein the container is a pool or spa.