# US 10,502,236 B2 · Blade for industrial axial fan and industrial axial fan comprising such blade > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,236 B2 - Document ID: US10502236B2 - Status: Granted - Kind: B2 - Application number: 15/309,870 - Filed: 2014-05-13 - Published: 2017-05-25 - Granted: 2019-12-10 - Earliest claimed: 2014-05-13 - Assignees: R.E.M. Holding S.R.L. - Applicants: R.E.M. Holding S.R.L. - Inventors: Roberto Edoardo Mosiewicz - Web page: https://patentgrep.com/patent/US10502236B2 ## CPC - F04D 29/362: {during rotation} - F04D 19/002: {Axial flow fans} - F04D 29/382: {Flexible blades} - F04D 29/668: {damping or preventing mechanical vibrations} - F05D 2240/301: Cross-sectional characteristics - F05D 2300/501: Elasticity - F05D 2300/603: Composites; e.g. fibre-reinforced - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A blade for an industrial axial fan including an attachment and an airfoil having a longitudinal axis, the attachment connecting the airfoil to a hub, wherein the attachment has a stiffness and a stiffness distribution that allows the attachment to deform in a way to have at least an inflection point along the longitudinal axis during the operation of the axial fan. The attachment includes a first part for connection to the hub and a second part for connection to a proximal end of the airfoil. The blade further includes a weight fixed at a distal end of the airfoil. The attachment has a decreasing stiffness along its longitudinal direction from the first part to the second part so that during the operation of the axial fan, the attachment deforms and includes the inflection point to thereby induce the blade to vibrate according to a second vibrating mode. ## Claims ### Claim 1 A blade for an industrial axial fan comprising: an attachment and an airfoil having a longitudinal axis, said attachment connecting the airfoil to a hub, wherein the attachment has a stiffness and a stiffness distribution that allows the attachment to deform in a way to have at least an inflection point along the longitudinal axis during the operation of the axial fan, wherein said attachment comprises a first part for the connection to the hub and a second part for the connection to a proximal end of the airfoil; wherein the attachment has a decreasing stiffness along its longitudinal direction from said first part to said second part so that during the operation of the axial fan, the attachment deforms and includes the inflection point to thereby induce the blade to vibrate according to a second vibrating mode. ### Claim 2 (depends on 1) The blade for an industrial axial fan according to claim 1, wherein said attachment comprises a necking zone. ### Claim 3 (depends on 2) The blade for an industrial axial fan according to claim 2 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 4 (depends on 2) The blade for an industrial axial fan according to claim 2, wherein said attachment has an I-shaped profile provided with lateral ribs. ### Claim 5 (depends on 4) The blade for an industrial axial fan according to claim 4 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 6 (depends on 4) The blade for an industrial axial fan according to claim 4, wherein the width and the length of the lateral ribs decrease in size spanwise, along the longitudinal direction. ### Claim 7 (depends on 6) The blade for an industrial axial fan according to claim 6 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 8 (depends on 1) The blade for an industrial axial fan according to claim 1, wherein said attachment has a cross-section with a wall-thickness which decreases along the longitudinal direction. ### Claim 9 (depends on 8) The blade for an industrial axial fan according to claim 8 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 10 (depends on 1) The blade for an industrial axial fan according to claim 1, wherein said attachment comprises a necking zone having a stiffness which is lower compared to the stiffness of both the first part and the second part. ### Claim 11 (depends on 10) The blade for an industrial axial fan according to claim 10 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 12 (depends on 1) The blade for an industrial axial fan according to claim 1, wherein said attachment has a quadrangular cross-section, a rectangular cross-section, a round cross-section, or an oval cross-section. ### Claim 13 (depends on 12) The blade for an industrial axial fan according to claim 12 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 14 (depends on 1) The blade for an industrial axial fan according to claim 1, wherein said attachment has a U-shaped cross-section profile having a pair of lateral ribs. ### Claim 15 (depends on 14) The blade for an industrial axial fan according to claim 14 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 16 (depends on 1) A method for the reduction of the energy transmitted from the blade in accordance with claim 1 to a structure of the industrial axial fan, the method comprising the step of providing the attachment for connecting the blade to the hub, said attachment having the stiffness and stiffness distribution that allows the attachment to deform with the inflection point during the operation of the axial fan. ### Claim 17 (depends on 1) An industrial axial fan characterized in that it comprises a blade according to claim 1. ### Claim 18 (depends on 1) The blade for an industrial axial fan according to claim 1 further comprising at least an additional weight fixed at a distal end of the airfoil. ### Claim 19 A method for reducing energy transmitted from a fan blade to a hub of an industrial axial fan, the method comprising providing an attachment for connecting the blade to the hub, wherein said attachment has a stiffness and a stiffness distribution that allows the attachment to deform in a way to have at least an inflection point during the operation of the axial fan, wherein said attachment comprises a first part for the connection to the hub and a second part for the connection to the fan blade, the blade includes a distal end having a weight affixed thereto; wherein the attachment has a decreasing stiffness along its longitudinal direction from said first part to said second part so that during the operation of the axial fan, the attachment deforms and includes the inflection point to induce the blade to vibrate according to a second vibrating mode.