# US 9,039,149 B2 · Liquid feeding device and method of determining time of exchange of gas control element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,149 B2 - Document ID: US9039149B2 - Status: Granted - Kind: B2 - Application number: 13/760,899 - Filed: 2013-02-06 - Published: 2013-09-19 - Granted: 2015-05-26 - Earliest claimed: 2010-08-31 - Assignees: SCREEN Holdings Co., Ltd. - Applicants: Dainippon Screen MFG. CO., LTD. - Inventors: Motoyuki Anno - Web page: https://patentgrep.com/patent/US9039149B2 ## CPC - B01D 19/0063: {Regulation, control including valves and floats (for construction and details of valves F16K)} - B01D 19/0031: {by filtration} - B01D 19/0036: {Flash degasification (the other groups take precedence)} - B01D 63/02: Hollow fibre modules - B41J 2/19: for removing air bubbles - B41J 2/195: for monitoring ink quality - B01D 2313/903: Integrated control or detection device - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract Ink in an ink tank is fed through a dissolved gas control filter to a printer head. A gas pressure changing mechanism reduces pressure in a gas pressure control tank. In response, the dissolved gas control filter removes gas dissolved in the ink. The gas pressure control tank is placed under pressure corresponding to a sum of the pressure reduced by the gas pressure changing mechanism and the pressure of the gas having been removed from the liquid. A gas pressure measuring part measures the sum of these pressures as pressure in the gas pressure control tank. Then, a controller determines when time of exchange of the dissolved gas control filter has come based on the magnitude of a gradient of gas pressure variation in the gas pressure control tank. ## Claims ### Claim 1 A liquid feeding device that feeds liquid through a feeding system to a predetermined mechanism, the liquid feeding device comprising dissolved gas processing part that processes dissolved gas in said liquid, said dissolved gas processing part including: a gas control element provided in said feeding system, the gas control element controlling the amount of gas dissolved in said liquid by using gas pressure acting on the gas control element; a pressure control tank functioning as a buffer for controlling the gas pressure acting on said gas control element; gas pressure changing part that changes gas pressure in said pressure control tank; gas pressure measuring part that measures gas pressure variation in said pressure control tank while said gas control element controls the amount of gas dissolved in said liquid fed through said feeding system, the gas pressure variation being caused based on the gas pressure change by said gas pressure changing part and the control of the amount of gas dissolved in said liquid by said gas control element; and gas control element exchange suggesting part that suggests a time of exchange of said gas control element has come when a gradient of the gas pressure variation in said pressure control tank obtained from a result of measurement of the gas pressure variation by said gas pressure measuring part becomes the same as or lower than a predetermined threshold. ### Claim 2 (depends on 1) The liquid feeding device according to claim 1, wherein said gas control element includes a hollow fiber membrane. ### Claim 3 (depends on 1) The liquid feeding device according to claim 1, further comprising maintenance sequence executing part that performs maintenance of a device including said dissolved gas processing part at given time, wherein said gas pressure measuring part measures the gas pressure variation in said pressure control tank while said maintenance sequence executing part performs operation for maintenance, and said gas control element exchange suggesting part suggests exchange of said gas control element when a result of measurement of the gas pressure variation by said gas pressure measuring part becomes the same as or lower than the predetermined threshold. ### Claim 4 (depends on 1) The liquid feeding device according to claim 1, wherein the gas pressure change in said pressure control tank by said gas pressure changing part is pressure reduction. ### Claim 5 (depends on 4) The liquid feeding device according to claim 4, wherein the pressure in said pressure control tank measured by said gas pressure measuring part is the sum of the pressure of the gas having been removed from said liquid by said gas control element and the pressure of the gas reduced by said gas pressure changing part. ### Claim 6 (depends on 1) The liquid feeding device according to claim 1, wherein said predetermined mechanism to receive liquid is a printer head of an ink-jet printer and said liquid is ink.