# US 10,307,700 B2 · Contamination indicator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,307,700 B2 - Document ID: US10307700B2 - Status: Granted - Kind: B2 - Application number: 14/628,328 - Filed: 2015-02-23 - Published: 2015-10-22 - Granted: 2019-06-04 - Earliest claimed: 2014-04-16 - Assignees: Hydac Filtertechnik GmbH - Applicants: Hydac Filtertechnik GmbH - Inventors: Artur Jung; Jörg Michael Wendels - Web page: https://patentgrep.com/patent/US10307700B2 ## CPC - B01D 35/143: Filter condition indicators - 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) ## Abstract A contamination indicator is for filter elements (12) for fluids that are replaceably housed in a filter housing (2). The indicator has a fluid-conveying connection (58) to the interior of the housing (2) and possesses an indicating device (52) providing information concerning the degree to which the filter element is contaminated (12). A temperature-dependently active actuation device (50) is connected upstream from the indicating device (52) in the direction of fluid inlet. By the actuation device, the indicating device (52) is activated when the fluid temperature has reached a predefinable threshold value. ## Claims ### Claim 1 A contamination indicator for filter elements for fluids housed in a filter housing, comprising: a fluid-conveying connection in fluid communication with a filter housing interior; an indicating device providing information of degree of filter element contamination and having a fluid inlet; and a temperature-dependent active actuation device being connected upstream of said indicating device in a direction of said fluid inlet of said indicating device and activating said indicating device when a temperature of fluid being filtered has reached a predefinable threshold value, said actuation device including a valve having a movable closing body with a body longitudinal axis, said closing body being biased toward a closed position blocking said fluid inlet of said indicating device and being movable into an open position opening said fluid inlet of said indicating device by a temperature-dependent active positioning device associated with said valve, said positioning device having an expansion element with an element longitudinal axis being connected upstream of said closing body in the direction of said fluid inlet, coming into contact with the fluid and being coupled with said closing body such that said closing body is moved along said body longitudinal axis into the open position through thermal expansion of said expansion element in a direction along said element longitudinal axis applied mechanically to said closing body and in a direction of the thermal expansion of said expansion element, said closing body including a valve spool guided in a valve cylinder forming a part of and being in fluid communication with said fluid inlet, said valve spool being movable in a direction thereof to an open position thereof by the expansion of said expansion element in which said spool releases an outlet of said valve cylinder leading to said indicting device. ### Claim 2 (depends on 1) A contamination indicator according to claim 1 wherein said indicating device comprises a differential pressure indicator detecting a pressure differential at the filter element during operation, said pressure differential indicator being in fluid communication with a clean side and a dirty slide of the filter element with pressure at the dirty and clean sides acting on said pressure differential indicator. ### Claim 3 (depends on 1) A contamination indicator according to claim 1 wherein said indicating device comprises a back pressure indicator in fluid communication with a dirty side of the filter element via said actuation device, pressure of the dirty side of the filter element acting on said back pressure indicator counter to static ambient pressure. ### Claim 4 (depends on 1) A contamination indicator according to claim 1 wherein said expansion element comprises an expansion body having one side on said closing body and an opposite side on a stationary part of said valve. ### Claim 5 (depends on 1) A contamination indicator according to claim 1 wherein a valve block houses said valve cylinder of said actuation device and said indicating device, said valve block having inner fluid connections for respective fluid inlets of said indicating device and said actuation device. ### Claim 6 (depends on 5) A contamination indicator according to claim 5 wherein said valve block comprises a connecting port being threadable into a connecting bore of a head section of a filter housing, having an inner fluid passage and forming a fluid-conveying connection to an interior of the filter housing via the connecting bore of the head section, said inner fluid passage being formed as part of said fluid inlet of said actuation device. ### Claim 7 (depends on 1) A contamination indicator according to claim 1 wherein said valve of said actuation device comprises a valve seat abutted by said closing body along said body longitudinal axis under pretensioning of a closing spring. ### Claim 8 (depends on 7) A contamination indicator according to claim 7 wherein said valve seat is in a valve housing having a fluid passage defined by a stepped bore extending through said valve housing, said stepped bore having a step forming said valve seat, said closing body comprising a valve ball. ### Claim 9 (depends on 8) A contamination indicator according to claim 8 wherein said valve housing comprises a connection part being on an inlet said of said stepped bore and forming a fluid connection to the dirty side of the filter element; and said expansion element comprises an expansion spring of a metal alloy having shape memory in an end section of said stepped bore adjacent to said connection part, said expansion spring expanding to a greater length upon heating, being supported on one end on said connection part and transmitting a dynamic force on said valve ball against a closing force of said closing spring with another end of said expansion spring upon heating of said expansion spring. ### Claim 10 (depends on 9) A contamination indicator according to claim 9 wherein said stepped bore comprises a narrowed section between said valve seat and said expansion spring; and a tappet extends through said narrowed section, one end of said tapped abutting said valve ball, said tappet having an actuation part supporting said expansion spring. ### Claim 11 (depends on 10) A contamination indicator according to claim 10 wherein said expansion spring is in a widened bore segment of said stepped bore, said widened bore segment being widened compared to said narrowed section adjacent said valve seat and receiving and movably guiding said actuation part of said tappet. ### Claim 12 (depends on 8) A contamination indicator according to claim 8 wherein said closing spring comprises a compression spring in a spring bore section of said stepped bore extending from said valve seat to an outlet end of said valve housing, said outlet end having a threaded section threadedly receiving a hollow adjustment screw, said closing spring having one end engaging said adjacent screw and an opposite end engaging said valve ball. ### Claim 13 (depends on 1) A contamination indicator according to claim 1 wherein said expansion element comprises an axial expansion spring of a metal alloy having shape memory, said expansion spring extending along a longitudinal axis of said expansion spring to a greater length upon heating thereof and being supported on one side on said closing body and on an opposite side thereof on a stationary part of said valve. ### Claim 14 (depends on 1) A contamination indicator according to claim 1 wherein said body longitudinal axis and said element longitudinal axis are parallel to a longitudinal axis of a filter element located in a filter housing. ### Claim 15 (depends on 14) A contamination indicator according to claim 14 wherein said body longitudinal axis and said element longitudinal axis are offset relative to the longitudinal axis of the filter housing. ### Claim 16 (depends on 1) A contamination indictor according to claim 1 wherein fluid communication between an inlet of the filter housing and said indicating device is blocked in closing body in the closed position thereof. ### Claim 17 A contamination indicator for filter elements for fluids housed in a filter housing, comprising: a fluid-conveying connection in fluid communication with a filter housing interior; an indicating device providing information of degree of filter element contamination and having a fluid inlet; and a temperature-dependent active actuation device being connected upstream of said indicating device in a direction of said fluid inlet of said indicating device and activating said indicating device when a temperature of fluid being filtered has reached a predefinable threshold value, said actuation device including a valve having a movable closing body with a body longitudinal axis, said closing body being biased toward a closed position blocking said fluid inlet of said indicating device and being movable into an open position opening said fluid inlet of said indicating device by a temperature-dependent active positioning device associated with said valve, said positioning device having an expansion element with an element longitudinal axis being connected upstream of said closing body in the direction of said fluid inlet, coming into contact with the fluid and being coupled with said closing body such that said closing body is moved along said body longitudinal axis into the open position through thermal expansion of said expansion element in a direction along said element longitudinal axis applied mechanically to said closing body and in a direction of the thermal expansion of said expansion element, said valve seat being in a valve housing having a fluid passage defined by a stepped bore extending axially through said valve housing, said stepped bore having a step forming said valve seat, said closing body comprising a valve ball, said valve housing including a connection part being on an inlet said of said stepped bore and forming a fluid connection to the dirty side of the filter element, said expansion element including an expansion spring of a metal alloy having shape memory in an end section of said stepped bore adjacent to said connection part, said expansion spring expanding to a greater length upon heating, being supported on one end on said connection part and transmitting a dynamic force on said valve ball against a closing force of said closing spring with another end of said expansion spring upon heating of said expansion spring. ### Claim 18 A contamination indicator for filter elements for fluids housed in a filter housing, comprising: a fluid-conveying connection in fluid communication with a filter housing interior; an indicating device providing information of degree of filter element contamination and having a fluid inlet; and a temperature-dependent active actuation device being connected upstream of said indicating device in a direction of said fluid inlet of said indicating device and activating said indicating device when a temperature of fluid being filtered has reached a predefinable threshold value, said actuation device including a valve having a movable closing body with a body longitudinal axis, said closing body being biased toward a closed position blocking said fluid inlet of said indicating device and being movable into an open position opening said fluid inlet of said indicating device by a temperature-dependent active positioning device associated with said valve, said positioning device having an expansion element with an element longitudinal axis being connected upstream of said closing body in the direction of said fluid inlet, coming into contact with the fluid and being coupled with said closing body such that said closing body is moved along said body longitudinal axis into the open position through thermal expansion of said expansion element in a direction along said element longitudinal axis applied mechanically to said closing body and in a direction of the thermal expansion of said expansion element, said valve of said actuation device including a valve seat axially abutted by said closing body along said body longitudinal axis under pretensioning of a closing spring, said valve seat being in a valve housing having a fluid passage defined by a stepped bore extending through said valve housing, said stepped bore having a step forming said valve seat, said closing body comprising a valve ball, said closing spring including a compression spring in a spring bore section of said stepped bore extending from said valve seat to an outlet end of said valve housing, said outlet end having a threaded section threadedly receiving a hollow adjustment screw, said closing spring having one end engaging said adjacent screw and an opposite end engaging said valve ball. ### Claim 19 A contamination indicator for filter elements for fluids housed in a filter housing, comprising: a fluid-conveying connection in fluid communication with a filter housing interior; an indicating device providing information of degree of filter element contamination and having a fluid inlet; and a temperature-dependent active actuation device being connected upstream of said indicating device in a direction of said fluid inlet of said indicating device and activating said indicating device when a temperature of fluid being filtered has reached a predefinable threshold value, said actuation device including a valve having a movable closing body with a body longitudinal axis, said closing body being biased toward a closed position blocking said fluid inlet of said indicating device and being movable into an open position opening said fluid inlet of said indicating device by a temperature-dependent active positioning device associated with said valve, said positioning device having an expansion element with an element longitudinal axis being connected upstream of said closing body in the direction of said fluid inlet, coming into contact with the fluid and being coupled with said closing body such that said closing body is moved along said body longitudinal axis into the open position through thermal expansion of said expansion element in a direction along said element longitudinal axis applied mechanically to said closing body and in a direction of the thermal expansion of said expansion element, said expansion element including an expansion spring of a metal alloy having shape memory, said expansion spring extending axially along a longitudinal axis of said expansion spring to a greater length upon heating thereof and being supported on one side on said closing body and on an opposite side thereof on a stationary part of said valve.