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AssigneeThermo Electron LED GmbH
InventorsGerhard Schuck, Patrick Fanta, Gerd Ross, Oliver Rupp, Christoph Noll
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The invention relates to a safety workbench (1) having a work space (3) surrounded by a housing (2) having a work opening (6) located in the housing front side (4) and adjustable with an adjustable front panel (5) for admitting into the work space (3) an air inlet flow (7), an exhaust blower (8) and a circulating air blower (9) for conveying an air flow (10) in the safety workbench (1), which are designed such that a partial air flow drawn in by the exhaust blower (8) is filtered through an exhaust air filter (11) as exhaust air flow (12) from the safety workbench (1) and a partial air flow drawn in by the circulating air blower (9) through a circulating air filter (13) as downwardly directed circulating air flow (14) into the work space (3), and a control device (15), a differential pressure sensor (16) and two pressure transducers (17, 18) connected thereto which are designed to measure a pressure at two different positions within the safety workbench d, wherein a first of the pressure sensors (17) is arranged in the immediate vicinity of the fan blades (90) on the low pressure side (91) of the circulating air blower (9) and a second of the pressure sensors (18) is arranged in a low-flow area, (20) on the low pressure side (91) of the circulating air blower (9). The invention further relates to a method of operating a safety workbench according to any of the preceding claims, comprising the steps of: a) determining a pressure difference between the first pressure transducer (17) and the second pressure transducer (18) by means of the differential pressure sensor (16), b1) comparing the pressure difference determined in a) with a nominal pressure difference stored in the control device (15), which corresponds to a nominal volume flow, or b2) converting the pressure difference measured in a) into an associated volume flow and comparing the calculated volume flow with one nominal volume flow stored in the control device (15), and c) regulating the circulating air blower (9) such that the nominal volume flow is conveyed.
A safety workbench comprising a work space surrounded by a housing having a work opening located in a housing front side and adjustable with an adjustable front panel (5) for admitting into the work space an air inlet flow, an exhaust blower and a circulating air blower for conveying an air flow in the safety workbench, which are designed such that a partial air flow drawn in by the exhaust blower is filtered through an exhaust air filter as exhaust air flow from the safety workbench and a partial air flow drawn in by the circulating air blower through a circulating air filter as downwardly directed circulating air flow into the work space, and a control device, a differential pressure sensor and two pressure transducers connected thereto which are designed to measure a pressure at two different positions within the safety workbench,
Dependencies are inferred from the claim text.