The field of the present embodiments is directed to printing devices and, more particularly, control of the emissions exhausted from photocopiers and the like. More particularly, the present embodiments are directed to reduce ultrafine particles (UFPs) and volatile organic compounds (VOC) emissions from the exhaust of the system, although those skilled in the art will appreciate that the embodiments are applicable to other types of electronic equipment.
Current photocopier products emit UFPs at high rates, peaking at over 250,000 counts within prescribed test print cycles.
The majority of UFPs emitted from such machines comprise water vapor released by the fuser heat, the water being originally contained in the paper, or the VOCs from materials such as the fuser web oil. Fusers are typically lubricated using silicone oil. These UFPs usually exist in a gas or liquid (vapor) phase and are transported out of the machine in cooling airstreams, coalesce and are counted as particles by particle counters.
Industry standards and regulations continue to demand emission quality improvements by reducing the UFP and VOC content in exhaust emissions. Thus there is a need for methods and systems to address and improve photocopier, and other electric equipment, exhaust emission quality.
The preferred embodiments exploit structure and methods for effecting surface condensation and coalescence of the UFPs on cooled surfaces within the machine to reduce UFP and VOC emissions from the machine. More particularly, a UFP particle removal assembly effects a cross-flow between cooling ambient air and the device exhaust emissions through an aluminum honeycomb so that heat transfer through the honeycomb walls effect condensation and/or coalescence through exhaust cooling for improved reduction and control of the UFPs.
More particularly, the subject embodiments comprise a printing device having UFP emissions including an UFP particle removal assembly. The assembly comprises a fluid conduit having a printing device emission input and output and an other fluid input and output wherein an emission portion of the conduit is affected by the other fluid portion and communication of the other fluid through the removal assembly effects a condensation/coalescence of the UFP emissions between the emission input and output for a reduction in UFP content of printing device emissions at the printing device emission output. The fluid conduit includes an interface between the emission portion and the other fluid portion for heat transfer from the emissions to the other fluid.
The subject embodiments are directed to the exploitation of surface condensation and coalescence of the UFPs on cooled surfaces within an exhaust assembly to a printing machine to reduce UFP and VOC emissions from the machine. More specifically, the use of a dual direction or “cross-flow” expanded aluminum honeycomb structure as the principal componentry of the removal assembly effectively controls, through condensation and/coalescence, the ultrafine particle reduction in exhaust emissions.
With particular reference to
With particular reference to
Honeycombs (such as those made of paper or aluminum) are made by a multi-stage process. Large thin sheets of the material (usually 1.2×2.4 m) are printed with alternating, parallel, thin strips of adhesive and the sheets are then stacked in a heated press while the adhesive cures. In the case of aluminum honeycomb, the stack of sheets is then sliced through its thickness. The slices (known as “block form”) are later gently stretched and expanded to form the sheet of continuous hexagonal cell shapes. The result is that air passing through the assembly 14 from one side 20 can only be emitted through an opposed output side 22. In addition, air entering from an orthogonal direction at side 24 can only exit through outputs 26. The result is a plurality of cross-flow planes each sealed from its adjacent plane so that the air in the first plane flows in an orthogonal direction from the air in any adjacent plane. Air flows in a first direction through conduit 28 and exhaust through an orthogonal direction in conduit 30.
In the subject embodiments, the UFP exhaust is directed so that the interface between the emission portion of the exhaust and the other fluid portion, such as ambient air, will flow orthogonally, respectively. Thus, as the exhaust air 12 flows through the assembly 14 it will be effectively cooled by the aluminum walls of the assembly 14 due to the flow of the cooling air on the opposite side of a wall from which the exhaust air is passing. With particular reference to
The model boundary conditions were defined as follows (with associated results):
The horizontal airflow (left to right), is hot humid air that would normally exit the machine directly, but at 100% humidity, it is predominantly UFPs and contains a significant amount of VOCs.
The action of the cross-flow honeycomb heat exchanger significantly reduces the humidity level of the exit air and thus reduces the UFP and VOC content.
It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.