US 4,786,295 AGranted

Filtration device for airborne contaminants

AssigneeGPAC, Inc.

InventorsEugene E. Newman, Anthony Natale, Thomas Natale

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Abstract

A filtration device for filtering airborne contaminants, such as airborne asbestos fibers, from the air, including a housing having an inlet for receiving contaminated air, an outlet for expelling filtered air outside of the housing, a filter, including a HEPA filter, in sealed communication with the inlet, and a blower within the housing for drawing air through the filter means and for expelling the filtered air through the outlet to the outside of the housing. A control and display system continuously senses differential air pressure within the housing and blower speed, converts the differential air pressure and blower speed to an air flow rate value and displays the air flow rate through a display unit. Manually controllable key pad switches are provided to selectively change the desired air flow rate, to set upper and lower pressure limit values, and to set the operating time for the system operation. When the system is set to operate at an air flow rate below the maximum air flow rate, the system automatically and continuously maintains the air flow rate at the selected value.

Claims16

Dependent claims

In a filtration device for filtering airborne contaminents, such as airborne asbestos fibers, from the air, said filtration device including a housing having an inlet for receiving contaminated air and an outlet for expelling filtered air outside the housing, a filter means within said housing including a HEPA filter in sealed communication across said inlet, a blower means within said housing for drawing air through said filter means and for expelling the filtered air through the outlet to the outside of the housing, the improvement comprising,

piezoelectric pressure sensing means for sensing the differential air pressure within said housing, downsteam of said filter means, from the air pressure outside of the housing, and for providing an electrical output signal indicative of the differential air pressure,
processing means for reading the differential air pressure output signal, determining the air flow rate through said housing based upon the differential air pressure output signal, calculating the average air flow rate through said housing during an operative period of the filtration unit blower means, timing an operative period of the filtration unit blower means, and for providing differential air pressure, air flow rate, average air flow rate, and operative time period information to an alphanumeric display means;
alphanumeric display means for visually displaying information processed and provided by said processing means;
manual control input means for selectively controlling the processing means to provide differential air pressure, air flow rate, average air flow rate, and operative time period information to said alphanumeric display means.

1 more element

A filtration device for filtering airborne contaminants, such as airborne asbestos fibers, from the air comprising,

a housing having an air inlet and an air outlet;
filter means within said housing in sealed engagement with said air inlet such that all of the inlet air passes through said filter means;
blower means within said housing for drawing air through said filter means and for expelling air through the air outlet of the housing;
pressure sensing means associated with said housing for sensing the differential air pressure within said housing, downstream of the filter means, with the air pressure outside of the housing, and for providing an electrical output signal indicative of the differential air pressure;
central processing means connected with said pressure sensing means, and with a memory means and a visual display means via a data/address bus;
memory means for storing air flow rates as a function of differential air pressures;
and
visual display means for visually displaying data provided by said central processing means;
wherein said central processing means reads the differential air pressure from said pressure sensing means, determines the air flow rate corresponding to said differential air pressure from said memory means, and provides data corresponding to said air flow rate to said visual display means.

6 more elements

Dependencies are inferred from the claim text.