WO2023229583A1 - Filtres à matière volatile - Google Patents

Filtres à matière volatile Download PDF

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Publication number
WO2023229583A1
WO2023229583A1 PCT/US2022/030728 US2022030728W WO2023229583A1 WO 2023229583 A1 WO2023229583 A1 WO 2023229583A1 US 2022030728 W US2022030728 W US 2022030728W WO 2023229583 A1 WO2023229583 A1 WO 2023229583A1
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WO
WIPO (PCT)
Prior art keywords
gas
filter
volatile material
recovery
operational state
Prior art date
Application number
PCT/US2022/030728
Other languages
English (en)
Inventor
Doron Schlumm
Assaf PINES
Mark Sandler
Original Assignee
Hewlett-Packard Development Company, L.P.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hewlett-Packard Development Company, L.P. filed Critical Hewlett-Packard Development Company, L.P.
Priority to PCT/US2022/030728 priority Critical patent/WO2023229583A1/fr
Publication of WO2023229583A1 publication Critical patent/WO2023229583A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/0407—Constructional details of adsorbing systems
    • B01D53/0438—Cooling or heating systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/0015—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form for treating before, during or after printing or for uniform coating or laminating the copy material before or after printing
    • B41J11/002—Curing or drying the ink on the copy materials, e.g. by heating or irradiating
    • B41J11/0022—Curing or drying the ink on the copy materials, e.g. by heating or irradiating using convection means, e.g. by using a fan for blowing or sucking air
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • G03G15/107—Condensing developer fumes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/20—Humidity or temperature control also ozone evacuation; Internal apparatus environment control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/106—Silica or silicates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/106—Silica or silicates
    • B01D2253/11—Clays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
    • B01D2257/708—Volatile organic compounds V.O.C.'s
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0258—Other waste gases from painting equipments or paint drying installations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/06—Polluted air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/40083—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
    • B01D2259/40088—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating
    • B01D2259/4009—Regeneration of adsorbents in processes other than pressure or temperature swing adsorption by heating using hot gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/402—Further details for adsorption processes and devices using two beds

Definitions

  • Volatile materials are substances which may readily vaporise. Such materials may be useful in processes, such as industrial processes or printing. However there may be health and environmental concerns associated with their release into the environment or other locations. Therefore, there may be efforts to reduce the concentration of volatile materials in gasses which are exhausted from such processes.
  • Figure 1 is a simplified schematic drawing of an example apparatus
  • Figure 2A is a simplified schematic drawing of an example apparatus in a first operational state
  • Figure 2B is a simplified schematic drawing of an example apparatus in a second operational state
  • Figure 3 is a simplified schematic drawing of an example apparatus
  • Figure 4 is a flowchart of an example of a method for recovering volatile material from a gas
  • Figure 5 is a flowchart of another example of a method for recovering volatile material from a gas.
  • FIGS 6 and 7 are simplified schematic drawings of an example printing apparatus. DETAILED DESCRIPTION
  • Volatile materials are materials which have a high volatility, wherein volatility is a property of a material which describes how readily the material vaporizes.
  • a substance with high volatility may vaporize, boil or evaporate at, or near, room temperature and pressure, or at temperatures of processes in which it is used.
  • Volatile materials have many uses in industrial processes, for example as solvents. They may also be used in substances such as paints, inks or varnishes.
  • a colorant such as a dye or pigment may be mixed with a volatile material which acts as a solvent. When the mixture is deposited on a surface, such as a substrate (for example paper, card, plastic, or the like) the volatile material may evaporate (i.e. vaporize) leaving the colored pigment or dye on the surface.
  • Volatile materials are therefore often used in printing processes as a solvent.
  • Volatile materials include volatile organic compounds (VOCs), which are organic chemicals which have a low boiling point at standard atmospheric pressure and near room temperature (i.e. a high vapour pressure).
  • VOC volatile organic compounds
  • a VOC may be defined as an organic compound having a boiling point less than or equal to 250°C at standard atmospheric pressure.
  • VOCs include isoparaffinic fluids such as Isopar (e.g. Isopar L, Isopar H, Isopar M), hexane or Isopropyl alcohol (IPA).
  • Volatile materials such as VOCs
  • VOCs may be dangerous to human health or may harm the environment. Therefore, emission of VOCs may be regulated or controlled.
  • Processes which use volatile materials may therefore employ filtering to remove volatile materials from gasses which are exhausted from the process or exchanged between an environment of the process and its surroundings (e.g. an interior of an apparatus carrying out the process and a room the apparatus is located in).
  • volatile materials may be captured and disposed of, while in other examples the captured material may be recycled.
  • Volatile materials may condense at low temperatures, therefore some processes may reduce the volatile material concentration of their exhaust gasses by cooling the exhaust gas causing the volatile materials therein to condense to a liquid which may then be collected.
  • the collected liquid may be recycled, reused or safely disposed of. This reduces harm caused by emission of the volatile material and can also reduce costs associated with the process when the material is reused or recycled.
  • supplies of the volatile material and filters may be replenished or replaced less frequently if the volatile material and filters can be reused.
  • the exhaust gases may be cooled using an apparatus such as a heat exchanger to reduce the temperature of the exhaust gas.
  • a heat exchanger e.g. connected to a site chiller
  • This level may be determined by the operating temperature of the heat exchanger.
  • a heat exchanger which operates at 10°C may be able to reduce the exhaust concentration of an example volatile material of Isopar L to approximately 200ppm. It may not be practically possible to operate heat exchangers at significantly lower temperatures because at lower temperatures ice may form on cooling fins of the heat exchanger causing loss of efficiency. Ice formation may be removed by use of a defrosting cycle, however this may also lead to a reduction in efficiency.
  • Figure 1 shows an example of apparatus 100, which may be used for recovering volatile material from a filter.
  • a filter may comprise a porous material through which a fluid may permeate while trapping a material which is intended to be removed from the fluid.
  • the fluid may comprise a gas
  • the gas may comprise mainly air and may be from a process such as a printing process and the material intended to be removed may be a volatile material such as VOCs.
  • the apparatus 100 may be a printing apparatus or may be associated with a printing apparatus.
  • the apparatus 100 may be an apparatus for processing gas from a printing process.
  • printing may refer to depositing agents (e.g. inks, colorants) on a substrate or generating three dimensional objects using additive manufacturing.
  • the apparatus 100 comprises a heating module 102, a filter 104 to capture a volatile material and a recovery module 106.
  • capture includes adsorbing (i.e. adhesion to a surface of the filter material) or absorbing (i.e. entering the bulk of the filter material) material by the filter 104.
  • the filter 104 may be used to capture (e.g. adsorb or absorb) volatile material from a gas to reduce the concentration of volatile material in the gas. As the quantity of volatile material captured by the filter 104 increases, the ability of the filter 104 to capture more volatile material may reduce as the filter 104 becomes saturated with volatile material. When the ability to capture volatile material drops below a certain level, a filter 104 may be considered “full”, “used” or “saturated”. To continue to efficiently reduce volatile material concentration in a gas, the filter may be replaced or regenerated. Replacement of a filter may be inconvenient for a user or operator of an apparatus and when a filter is replaced the used volatile material captured by the used filter may not be recovered, for example the filter may be incinerated.
  • a filter may be inconvenient for a user or operator of an apparatus and when a filter is replaced the used volatile material captured by the used filter may not be recovered, for example the filter may be incinerated.
  • the type of volatile material adsorbed by the filter may not be identifiable to the entity processing the filter and so recovery and reuse of the volatile material may not be practical, resulting in incineration being used as a practical means for processing used filters.
  • the apparatus 100 allows the filter 104 to be regenerated so that the filter 104 may be reused and the volatile material captured by the filter 104 can be captured for recycling or reuse.
  • the volatile material adsorbed by the filter 104 may be a VOC, such as Isopar (e.g. Isopar L).
  • the heating module 102 is to supply heated gas 108 with a first volatile material concentration to the filter 104.
  • the heating module 102 may comprise any suitable type of heating apparatus for heating the gas, for example the heating module may comprise an electrical heater, such as a resistive heater.
  • the heating module 102 may comprise a resistive heating element located in a gas stream (i.e. within a duct or pipe through which a gas flows).
  • the heating carried out by the heating module 102 may, at least in part, be part of another process, for example a process of drying a printing fluid on a substrate may include heating the printing fluid.
  • the heated gas 108 may be heated to at least 100°C or a temperature of approximately 180°C.
  • the temperature of the heated gas is less than the autoignition temperature of the volatile material.
  • the autoignition temperature of Isopar L may be 220°C. Therefore, when the volatile material is Isopar L, the temperature of the heated air may be less than 200°C (for example approximately 180°C) to ensure the Isopar L does not ignite.
  • the filter 104 is to output gas 110 with a second volatile material concentration, wherein the second volatile material concentration is higher than the first volatile material concentration.
  • the filter 104 may be a “used” filter i.e. it may have been used to adsorb volatile material from a gas and therefore contains adsorbed volatile material.
  • Use of the apparatus 100 may cause the filter 104 to be regenerated by reducing the quantity of volatile material in the filter 104.
  • the heated gas 108 is supplied to the filter 104 at a temperature which causes the volatile material to evaporate or vaporize, thereby increasing the concentration of volatile material in the gas output from the filter 104 relative to the heated gas 108 input to the filter 104.
  • a relatively small flow rate of heated gas 108 to the filter 104 may also contribute to increasing the concentration of volatile material in the gas output from the filter 104 relative to the heated gas 108 input to the filter 104. This also results in a reduction of the quantity of volatile material in the filter 104, thereby regenerating the filter 104 to allow it to be used again in a filtering role to remove volatile material from a gas. Regeneration of the filter 104 may reduce waste and costs associated with disposing of and replacing filters because it allows a filter to be reused multiple times.
  • the recovery module 106 is to recover liquid volatile material from gas 110 which has passed through the filter 104.
  • the gas 110 which has passed through the filter 104 has an increased concentration of volatile material due to the evaporation or vaporization of volatile material from the filter 104.
  • the recovery module 106 may use any suitable means to recover the volatile material from the gas 110 which has passed through the filter 104, for example it may cool the gas 110 and/or increase the pressure of the gas 110 to cause condensation of the volatile material. Condensed volatile material may then be collected. The collected volatile material may be recycled or reused in a process within the apparatus 100 or in a different process.
  • the gas 110 which has passed through the filter 104 may be provided directly to the recovery module 106 without participating in any other substantial process.
  • the gas 110 which has passed through the filter 104 may be used in another process within the apparatus 100, for example the gas 110 may be useful due to its high temperature and therefore may be used in a process which uses hot gas or elevated temperatures.
  • the gas 108, 110 may be routed within the apparatus via any suitable ducting.
  • the apparatus 100 may also include blowers or fans to cause the gas to move through the ducting and the other components of the apparatus described herein.
  • Figure 2A and Figure 2B show an example of an apparatus 200 in a first operational state and an apparatus 200’ in a second operational state, respectively.
  • the apparatus 200, 200’ may be an example of the apparatus 100 described with respect to Figure 1.
  • the arrows in Figures 2A and 2B indicate routing of gas within the apparatus 200. Relative volumes of gas may be indicated by the thickness of the arrows i.e. a thicker arrow may indicate a greater volume of gas than a thinner arrow. In practical examples, the gas would be routed within pipes or ducting.
  • the apparatus 200 comprises a heating module 202, a first filter 204 and a heat exchanger 206, which may correspond to the heating module 102, the filter 104 and recovery module 106 of Figure 1 , respectively.
  • the apparatus 200 further includes a second filter 212.
  • Figure 2A shows the apparatus 200 in a first operational state.
  • the first filter 204 is being regenerated i.e. the quantity of volatile material in the first filter 204 is being reduced, or ‘desorbing’ and the second filter 212 is actively filtering e.g. it is adsorbing volatile material.
  • the heating module 202 heats gas to an elevated temperature.
  • the heated gas 208 from the heating module 202 is provided to the first filter 204.
  • the heated gas 208 causes volatile material in the first filter 204 to evaporate causing the first filter 204 to release captured volatile material into the gas.
  • the first filter 204 therefore outputs gas 210 with an increased volatile material concentration to the heat exchanger 206.
  • the output gas 210 from the first filter 204 may be cooled before entering the heat exchanger 206 (for example by a second heat exchanger, as described in further detail below).
  • the recovery module is a heat exchanger 206 and recovers liquid volatile material by reducing the temperature of the gas causing the volatile material to condense.
  • a heat exchanger may be an apparatus which transfers heat between two fluids.
  • the heat exchanger 206 is used to transfer heat away from the gas, causing it to be cooled thereby reducing the temperature of the gas.
  • any other suitable means for cooling the gas may be used, such as refrigeration.
  • the gas 210 which has passed through the first filter 204 has an increased temperature and an increased volatile material concentration relative to the gas 214 input to the heating module 202.
  • the heat exchanger 206 may also, as shown in this example, have a further gas input 216.
  • the gas received at gas input 216 may be gas extracted from an apparatus which releases VOCs, such as a printing apparatus.
  • Gas 210 which has passed through the first filter 204 and the gas input 216 may be mixed prior to entering the heat exchanger 206 or mixed within the heat exchanger 206.
  • the concentration of VOCs in gas emitted by a process such as a printing process may initially be increased by the addition of gas 210 recovered from the first filter 204, before being reduced by the heat exchanger 206.
  • the condensed volatile material may be collected and recycled or reused.
  • the volatile material may be reused in a process within the apparatus 200, or a process associated with the apparatus 200.
  • the apparatus 200 is a printing apparatus or an apparatus associated with a printing process
  • the recovered volatile material may be reused in the printing process.
  • the collected volatile material may undergo some additional processing before it can be reused.
  • a portion of the gas 214 output from the heat exchanger 206 is supplied to the heating module 202 to be heated to form the heated gas 208 with the first volatile material concentration.
  • this gas 214 which is input to the heating module 202 has a relatively low concentration of volatile material (e.g. approximately 200ppm). Therefore, the heated gas 208 which is provided to the first filter 204 also has a relatively low concentration of volatile material (e.g. approximately 200ppm).
  • This gas 208 with a relatively low volatile material concentration and relatively high temperature causes a volatile material captured in the first filter 204 to evaporate at a relatively high rate, thereby increasing the efficiency of regeneration of the first filter 204 for reuse.
  • the gas flow 214 may be provided from some other source.
  • the heating module 202 may heat the gas 208 to a temperature of at least 100°C, for example 180°C.
  • the temperature of the heated gas 208 may be less than the autoignition temperature of the VOC under consideration.
  • the temperature may be less than 220°C or less than 200°C.
  • the apparatus 200 further comprises a second filter 212, wherein the second filter 212 is to capture volatile material from a portion of the gas 218 output from the heat exchanger 206.
  • the gas may then be exhausted from the apparatus 200 after passing through the second filter 212.
  • the gas may be heated prior to being exhausted from the apparatus to avoid cooling the environment around the apparatus 200 and/or to remove heat from the interior of the apparatus 200, thereby cooling the apparatus 200, as described in greater detail below.
  • the second filter 212 may be substantially the same as the first filter 204 in terms of its construction (i.e. materials, dimensions, shape, etc.).
  • at least one of the first filter 204 and the second filter 212 comprise a silica gel, activated carbon or a zeolite.
  • the second filter 212 receives gas 218 output from the heat exchanger 206 and captures volatile material from said gas 218 to reduce the concentration of volatile material in the gas 218, for example by adsorbing the volatile material.
  • Gas 220 is exhausted from the second filter 212 after it has passed through the second filter 212.
  • the concentration of gas 220 exhausted from the second filter 212 may be lower than, and in some examples significantly lower than, the concentration of the gas 218 received by the filter.
  • the gas received by the second filter 212 i.e. gas output by the heat exchanger
  • the gas 220 exhausted by the second filter 212 may have a volatile material concentration of less than 10ppm.
  • the concentration of volatile material exhausted from the second filter 212 is low, it may safely be exhausted from the apparatus, for example into a room in which the apparatus is located or into the environment.
  • the temperature of this gas may be relatively low because it has passed through the heat exchanger 206 which uses low temperatures (e.g. approximately 10°C) to recover volatile material. Therefore, the exhaust gas may pass through a second heat exchanger, referred to as an ‘economiser’, before being vented from the apparatus 200 to the room or environment.
  • a second heat exchanger may use the cool exhaust gas 220 to reduce the temperature of the gas 216 input to the heat exchanger 206 to further increase efficiency of recovery of volatile material.
  • the gas 216 input to the heat exchanger 206 may be from an industrial process and therefore may have a relatively high temperature, for example in the range 100°C to 200°C.
  • the gas from the process may be cooled by the economiser to a temperature of 30°C to 40°C prior to being input to the heat exchanger 206 which may further cool the gas to approximately 10°C.
  • the exhaust gas 220 may have a temperature of approximately 10°C prior to passing through the second heat exchanger (i.e. the economiser), which may heat the exhaust gas, for example to room temperature (i.e. around 20°C to 25°C). Therefore, the exhaust gas 220 may be vented from the economiser of the apparatus 200 to a room without adversely affecting the temperature in the room and without releasing gas with a harmful concentration of volatile material.
  • the flow rate of gas through the second filter 212 may be greater than the flow rate of gas through the heating module 202 and first filter 204 in the first operational state. Conversely in the second operating state the flow rate of gas through the first filter 204 may be greater than the flow rate of gas through the heating module 202 and the second filter 212. Therefore, a relatively small portion of the gas 214 output from the heat exchanger 206 is used to regenerate the filter and the bulk of the gas is directed through the filter which is actively filtering volatile material. The regeneration process may be operated efficiently with a relatively low flow rate.
  • the ratio of gas passing through the heating module 202 and first filter 204 relative to the second filter 212 may be 3:10.
  • the flow rate of gas through the heat exchanger may be approximately 100 litres per second (l/s) resulting in approximately 23 l/s of gas through the heating module 202 and first filter 204 and 77 l/s through the second filter 212.
  • the flow rates may vary depending on size and desorption efficiency of the filters 204, 212, which may depend on gas temperature and mechanical configuration of the filters 204, 212.
  • the output of the heat exchanger may be split and flow to the first filter 204 (via the heating module 202) and to the second filter 212.
  • a greater volume of gas may flow to the second filter 212 than the first filter 204, for example the flow rate of gas through the second filter 212 may be 3 to 10 times greater than the flow rate through the first filter 204.
  • the ratio of gas flow rate through the heating module 202 and second filter 212 relative to the first filter 204 is 3:10.
  • a relatively small flow rate of gas through the regenerating filter and a relatively high flow rate through the active filter may contribute to increasing the volatile material concentration in the gas output from the regenerating filter relative to the concentration in the gas output from the active filter.
  • the second filter 212 actively removes volatile material from a gas.
  • the first filter 204 is being regenerated i.e. volatile material which has been captured (e.g. adsorbed) by the first filter 204 is being removed from the first filter 204.
  • the apparatus 200 may be switched to a second operational state in which the first filter 204 and the second filter 212 switch roles. This allows one filter to be actively filtering volatile material from a gas while the other filter is being regenerated, allowing substantially continuous filtration of volatile material from a gas. Furthermore, this means the filters may be reused without replacement and the volatile material captured by the filters may be efficiently recovered for recycling or reuse.
  • the apparatus 200 further comprises a controller 222.
  • the controller 222 is to control the apparatus 200 to be in a first operational state and to control the apparatus 200’ to be in the second operational state by altering a routing of gas in the apparatus.
  • the controller 222 may be implemented, at least in part, by processing circuitry executing machine readable instructions.
  • the heating module 202 supplies heated gas 208 to the first filter 204
  • the heat exchanger 206 recovers liquid volatile material from gas 210 which has passed through the first filter 204 and the second filter 212 captures (e.g. adsorbs) volatile material from gas 218 output from the heat exchanger 206.
  • Figure 1 shows the apparatus to be the first operational state.
  • Figure 2B shows an apparatus 200’ in a second operational state.
  • the apparatus 200’ in the second operational state is substantially the same as the apparatus 200 in the first operational state depicted by Figure 2A, however the routing of the gas has been altered such that the roles of the first filter 204 and the second filter 212 have been swapped.
  • the heating module 202 supplies heated gas 208’ to the second filter 212, the heat exchanger 206 recovers liquid volatile material from gas 210’ which has passed through the second filter 212 and the first filter 204 captures (e.g. adsorbs) volatile material from gas 218’ output from the heat exchanger 206.
  • the second filter 212 can be regenerated for reuse while the first filter 204 is actively filtering and the first filter 204 can be regenerated for reuse while the second filter 212 is actively filtering.
  • This arrangement may be suitable when the time taken for a filter to be regenerated is less than or equal to the time taken for an active filter to become saturated.
  • the apparatus 200 comprises two filters, however in other examples the apparatus 200 may comprise more than two filters.
  • the time taken for a filter to be regenerated may be longer than the time taken for a filter to become saturated with volatile material. For example if the time taken for a filter to be regenerated was twice the time taken for an active filter to become saturated, then the apparatus may comprise three filters.
  • the controller 222 is to cycle the apparatus 200 between the first operational state and the second operational state. Cycling the apparatus between operational states may comprise altering routing of gas through the apparatus, for example by controlling valves as described in relation to Figure 3. In this way the apparatus 200 may substantially continuously filter volatile material from a gas. In examples where there are more than two filters the controller 222 may cycle the apparatus 200 between further operational states (e.g.
  • an apparatus with three filters may have three operational states), wherein in each state, one filter is actively filtering and two filters are regenerated, such that two different filters perform filtering for half the period that the third filter is regenerating (and are themselves regenerating for different other half of the prior for which the third filter is regenerating).
  • each of the filters may operate on a cycle, wherein the cycles of the filters are offset from one another.
  • additional operational states for example comprising a state in which at least one filter is neither actively filtering or actively being generated.
  • additional operational states may comprise part of the cycle, for example an additional operational state may be a cooling state, in which cool gas may be passed through a filter to cool the filter after the filter has been regenerated with heated gas and prior to using the filter capture volatile material.
  • Figure 2A depicts gas 210 from the first filter and Figure 2B depicts gas 210’ from the second filter 212 being input to the heat exchanger 206.
  • this gas 210, 210’ is used in a process in the apparatus 200 prior to being input to the heat exchanger 206.
  • This gas 210, 210’ has been heated and therefore may be useful for a process which uses heated air.
  • the apparatus 200 may be a printing apparatus and the gas 210, 210’ may be used in an air knife.
  • the heated gas may be used to warm gas to be output to the environment in the economiser.
  • Figure 3 is an example of an apparatus 300, which may be an example of apparatus 200 depicted in Figures 2A and 2B.
  • the apparatus 300 comprises heating module 202, first filter 204, heat exchanger 206, second filter 212 and controller 222 described in relation to Figures 2A and 2B.
  • the apparatus 300 further comprises valves 302, 304, 306, 308.
  • the controller 222 is to control the valves 302, 304, 306, 308 to adjust the routing of gas in the apparatus 300 between the first operational state and the second operational state.
  • the solid and dashed arrows of Figure 3 indicate the routing of gas in the first operational state and the second operational state, respectively.
  • Figure 3 indicates the routing of gas to and from the valves 302, 304, 306, 308 and does not indicate all other features of the apparatus 300.
  • the valves 302, 304, 306, 308 may be three way valves. Such valves may be switched between a first state and a second state.
  • a first valve 302 and a third valve 306 of the valves comprise two inputs and one output, and when these valves are switched between the first and second states, the routing of gas is switched between a first and a second of the inputs of each valve.
  • a second valve 304 and a fourth valve 308 of the valves comprise one input and two outputs, and when these valves are switched between the first and second states the routing of gas is switched between a first and a second of the outputs.
  • gas flows from the heating module 202 via the first valve 302 to the first filter 204, and from the first filter 204 via the second valve 304 to the heat exchanger 206.
  • gas also flows from the heat exchanger 206 via the third valve 306 to the second filter 212, and from the second filter 212 via a fourth valve 308 after which it is exhausted from the apparatus 300.
  • gas flows from the heating module 202 via the first valve 302 to the second filter 212, and from the second filter 212 via the second valve 304 to the heat exchanger 206.
  • gas also flows from the heat exchanger 206 via the third valve 306 to the first filter 204, and from the first filter 204 via the fourth valve 308 after which it is exhausted from the apparatus 300.
  • a gas 310 which is to be filtered is input to the heat exchanger 206 and a gas 312 is exhausted from the apparatus 300.
  • valves 302, 304, 306, 308 can be controlled, by the controller 222, to switch the apparatus 300 between the first and second operational states, thereby switching the roles of the first filter 204 and the second filter 212.
  • the fourth valve 308 may not be present in the apparatus and instead the gas may be exhausted from the apparatus 300 after passing through the active filter (i.e. the second filter 212 in the first operational state or the first filter 204 in the second operational state).
  • the gas may be routed for use in another process of the apparatus after passing through the second valve 304. This gas has been heated and so it may be useful for processes which uses heated gas.
  • the gas may be routed after the second valve 304 to an air knife. Air knives are described in more detail in relation to Figure 7. A blower, a fan or a vacuum pump may then be used to direct or suck gas which has been jetted by the air knife to be input into the heat exchanger 206.
  • the blower, fan or vacuum pump may also direct or suck gas which was not jetted from the air knife into the input of the heat exchanger.
  • This additional gas may be from a process associated with the apparatus 300, for example the gas may be associated with a printing process, for example from the interior of a printing apparatus.
  • Figure 4 is an example of a method, which may comprise a method for recovering volatile material from a gas.
  • the gas may be a gas associated with a printing process, for example it may be a gas extracted from an interior of a printing apparatus.
  • the method comprises, in block 402, heating a gas.
  • the gas may be heated using a heating module as described in relation to Figures 1 to 3.
  • the gas to be heated may undergo some processing prior to being heated, for example it may undergo a process to reduce the concentration of volatile material in the gas.
  • the concentration of volatile material in the gas to be heated may be reduced by a recovery module or heat exchanger as described in relation to Figures 1 to 3.
  • the method comprises, in block 404, providing the heated gas to a filter containing a captured (e.g. absorbed or adsorbed) volatile material to decrease a quantity of volatile material in the filter and increase a volatile material concentration in the heated gas.
  • the filter may be a filter which was used to absorb or adsorb volatile material from a gas and has become loaded, or saturated, with the volatile material. Therefore, the filter may have captured a significant quantity of volatile material. Passing the heated gas through the filter may cause the volatile material in the filter to evaporate, thereby reducing the quantity of volatile material in the filter.
  • the heated gas may be passed through the filter until the quantity of volatile material in the filter has reduced to a low enough level such that the filter may be reused to filter volatile material from a gas again, thereby regenerating the filter for reuse.
  • the filter may correspond to the filter 104 described in relation to Figure 1 or the first filter 204 described in relation to Figures 2A, 2B and 3.
  • the method comprises, in block 406, providing gas which has passed through the filter to a recovery apparatus to recover volatile material from the gas.
  • the recovery apparatus may be any apparatus suitable for recovering volatile material from a gas.
  • the recovery apparatus may cool and/or compress the gas to cause the volatile material to condense.
  • the recovery apparatus may be a recovery module as described in relation to Figure 1 and/or a heat exchanger as described in relation to Figures 2A, 2B or 3.
  • Figure 5 provides an example of the method of Figure 4.
  • blocks 502 to 504 may provide an example of the method of blocks 402 to 404 described in relation to Figure 4.
  • Block 502 comprises heating a gas, and may correspond to block 402 of Figure 4.
  • Block 504 comprises providing the heated gas to a first filter containing a captured volatile material to decrease a quantity of volatile material in the first filter and increase a volatile material concentration in the heated gas and may correspond to block 404 of Figure 4.
  • Block 506 comprises mixing gas which has passed through the first filter with a gas from an industrial process (e.g. a printing process).
  • Block 508 comprises providing the mixed gases to the recovery apparatus to recover volatile material from the gas from the printing process.
  • the heated gas has higher volatile material concentration than the gas from the printing process. Therefore, the higher concentration of volatile material in the heated gas causes the overall concentration of volatile material input to the recovery apparatus to be increased.
  • the recovery apparatus may be able to operate more efficiently when the gas input to the recovery apparatus comprises a higher concentration of volatile material. Therefore, by using the heated gas which has been used to reduce the quantity of volatile material in the first filter during regeneration of the first filter as an input to the recovery apparatus, the overall efficiency of recovery of the volatile material by the recovery apparatus may be increased.
  • the method therefore provides a means for regenerating used filters so that they can be reused and also results in increased recovery of volatile material by the recovery apparatus.
  • Block 510 comprises filtering output gas of the recovery apparatus by a second filter to reduce volatile material concentration of the output gas of the recovery apparatus.
  • the output gas of the recovery apparatus may be passed through the second filter as described in relation to Figures 2A and 3.
  • the second filter is to capture (e.g. absorb or adsorb) volatile material in gasses which pass through it.
  • the gas output from the recovery apparatus may comprise approximately 200ppm volatile material and the same gas after passing through the second filter may comprise less than 10ppm.
  • the gas may be exhausted to a surrounding environment.
  • the gas may be heated prior to being exhausted.
  • the gas may pass through a second heat exchanger (i.e. an economiser) prior to being exhausted to increase the temperature of the gas.
  • the second heat exchanger may also be used to decrease the temperature of gas which is provided to the recovery apparatus.
  • the second heat exchanger therefore may increase the efficiency of the recovery apparatus by pre-cooling the gas provided thereto.
  • the second heat exchanger may also raise the temperature of the exhausted gas so that it is close, or closer, to that of the environment (e.g. to room temperature).
  • Block 512 comprises cycling between a first operational state and a second operational state.
  • the first and second operational states may be the states described in relation to Figures 2A and 2B, respectively. In practice, this may comprise controlling gas flows by controlling valves or the like. In some examples, the cycles may include a portion of time in which the filters are neither actively filtering nor actively being generated.
  • the heated gas is provided to the first filter to decrease the quantity of volatile material in the first filter and increase the volatile material concentration of the heated gas, and output gas of the recovery apparatus is filtered by the second filter to reduce volatile material concentration of the output gas of the recovery apparatus.
  • the heated gas is provided to the second filter to decrease the quantity of volatile material in the second filter and increase the volatile material concentration of the heated gas, and output gas of the recovery apparatus is filtered by the first filter to reduce volatile material concentration of the output gas of the recovery apparatus.
  • the first and second operational states may be used alternately to regenerate the first filter and to actively filter gas using the second filter and vice versa.
  • the first and second operational states may be cycled every N minutes, wherein N may depend on the filter material, dimensions, material to be captured and type of gas.
  • the quantity of captured volatile material may be measured and monitored and the operational states may be cycled in response to determining a filter has been regenerated or has become saturated.
  • the filters could be weighed to monitor their weight, from which the quantity of captured volatile material could be determined.
  • the quantity of gas which has passed through the filters could be measured and the operational states cycled when a threshold quantity of gas is reached.
  • the filters may each be cycled between a state in which they are capturing volatile compounds and a state in which they are being regenerated (wherein in some examples the cycles may include a state in which a filter is neither actively filtering nor actively being generated).
  • the cycles of each filter are offset from one another.
  • Figure 6 is an example printing apparatus 600.
  • the printing apparatus 600 may be a Liquid Electrophotographic (LEP) printer, laser printer, inkjet printer or additive manufacturing apparatus (e.g. a 3D printer).
  • LEP Liquid Electrophotographic
  • the printing apparatus 600 may be an example of the apparatus described in relation to Figures 1 , 2A, 2B or 3 and may carry out the methods described in Figures 4 or 5.
  • the printing apparatus 600 comprises a first filter 602, a second filter 604 and a recovery module 606.
  • the first filter 602 may correspond to the filter 104 described in relation to Figure 1 or the first filter 204 described in relation to Figures 2A, 2B or 3.
  • the printing apparatus 600 may also comprise printing apparatus components such as print head(s), at least one print agent supply, and the like.
  • the print apparatus is a ‘two dimensional’ printer, it may for example comprise a LEP printer, a laser printer, an inkjet printer or the like, and may comprise a print head, substrate handling system, sources of print agents, inks or toner, and the like.
  • the printer is a ‘three dimensional’ printer, it may comprise, or be associated with, a print bed, a fabrication chamber, a print head, at least one energy source, a source of build material, or the like.
  • the recovery module 606 is to recover volatile material from a gas 608.
  • the recovery module 606 may correspond to the recovery module 106 of Figure 1 or the heat exchanger 206 of Figures 2A, 2B or 3.
  • the recovery module may cool and/or compress the gas 608 to cause the volatile material in the gas to condense. The volatile material may then be collected, reused or recycled.
  • the first filter 602 may have been used to filter volatile material from a gas. Therefore, in this example the first filter 602 contains a captured (e.g. absorbed or adsorbed) volatile material.
  • the first filter 602 may have been used to filter volatile material from gas passed through the first filter 602 by capturing the volatile material. In use of the printing apparatus 600 the captured volatile material is to be released from the first filter 602 to increase volatile material concentration of the gas 608 provided to the recovery module 606.
  • the second filter 604 is to capture (e.g. absorb or adsorb) volatile material to reduce volatile material concentration of a gas 610 received from a printing operation.
  • Printing operations may use volatile materials which evaporate during or after the printing operation.
  • the gas associated with the printing operation e.g. from the interior of the printing apparatus
  • the printing apparatus 600 may further comprise the components described in relation to Figures 1 to 3.
  • the recovery module 606 may provide gas to the first filter 602 via a heater and to the second filter 604. Gas which has passed through the second filter may be exhausted from the apparatus. Gas from a printing process within the printing apparatus 600 may be input to the recovery module 606.
  • the printing apparatus 600 is shown in a first operational state, wherein the first filter is being regenerated (i.e. the amount of captured volatile material therein is being reduced) and the second filter 604 is actively filtering volatile material from a gas 610.
  • the printing apparatus 600 may further comprise a controller (for example a controller 222), wherein the controller may cause the roles of the filters 602, 604 to be switched.
  • the controller may control a series of valves which control the routing of gas within the printing apparatus 600 as described in relation to Figure 3.
  • the controller may therefore control the printing apparatus 600 to be in a first operational state, as shown in Figure 6 or to be in a second operational state, in which the roles of the filters is reversed (i.e. the first filter 602 is actively filtering and the second filter 604 is being regenerated).
  • a controller may also control print operations, although in other examples a separate controller may be provided for this purpose.
  • Figure 7 is an example printing apparatus 700, which may be an example of the printing apparatus 600 of Figure 6.
  • the printing apparatus 700 comprises the first filter 602, the second filter 604 and the recovery module 606 described in relation to Figure 6.
  • the gas 608 provided to the recovery module 606 passes through the first filter 602 and is subsequently used in a printing process.
  • the gas entering the first filter 602 is heated, for example by a heating module as described in relation to Figures 1 to 3. The elevated temperature of this gas may be utilised in a process within the printing apparatus.
  • the printing process comprises using the gas in an air knife 702.
  • the air knife 702 may comprise a constriction, such as small orifices or a narrow slot, through which the gas passes.
  • the constriction causes an increase in the velocity of the gas, which may be jetted for use in a process.
  • the gas jetted from the air knife 702 may be directed towards print agent which has been deposited on a substrate to increase the rate at which the agent dries, or it may be used to remove dust or debris from a substrate prior to printing.
  • the air knife 702 may direct gas towards a surface to break a boundary layer of gas at the surface, thereby increasing the rate of evaporation of a fluid from the surface.
  • an air knife may be used to clean a printing surface of a print apparatus, for example a photoconductive imaging plate on which an image may be formed prior to be applied to a substrate.
  • the gas jetted by the air knife may be received by an inlet 704 to the recovery module 606.
  • a blower, fan or vacuum pump may be used to direct or suck gas jetted from the air knife 702 to the inlet 704.
  • At least one of the first filter 602 and the second filter 604 comprises silica (e.g. a silica gel), activated carbon or a zeolite.
  • silica e.g. a silica gel
  • activated carbon e.g. a zeolite
  • a filter which comprises silica gel may adsorb up to 11 % of its weight in VOCs.
  • Examples in the present disclosure can be provided as methods, systems or machine readable instructions, such as any combination of software, hardware, firmware or the like.
  • Such machine readable instructions may be included on a computer readable storage medium (including but not limited to disc storage, CD-ROM, optical storage, etc.) having computer readable program codes therein or thereon.
  • the machine readable instructions may, for example, be executed by a general purpose computer, a special purpose computer, an embedded processor or processors of other programmable data processing devices to realize the functions described in the description and diagrams.
  • a processor or processing apparatus may execute the machine readable instructions.
  • functional modules of the apparatus and devices may be implemented by a processor executing machine readable instructions stored in a memory, or a processor operating in accordance with instructions embedded in logic circuitry.
  • the term ‘processor’ is to be interpreted broadly to include a CPU, processing unit, ASIC, logic unit, or programmable gate array etc.
  • the methods and functional modules may all be performed by a single processor or divided amongst several processors.
  • Such machine readable instructions may also be stored in a computer readable storage that can guide the computer or other programmable data processing devices to operate in a specific mode.
  • Such machine readable instructions may also be loaded onto a computer or other programmable data processing devices, so that the computer or other programmable data processing devices perform a series of operations to produce computer-implemented processing, thus the instructions executed on the computer or other programmable devices realize functions specified by block(s) in the flow charts and/or block diagrams.
  • teachings herein may be implemented in the form of a computer software product, the computer software product being stored in a storage medium and comprising a plurality of instructions for making a computer device implement the methods recited in the examples of the present disclosure.

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Abstract

Un exemple de l'invention concerne un appareil comprenant un module de chauffage, un filtre destiné à capturer une matière volatile et un module de récupération. Dans certains exemples, le module de chauffage est destiné à fournir du gaz chauffé avec une première concentration de matière volatile au filtre. Le filtre peut délivrer en sortie du gaz avec une deuxième concentration de matière volatile, la deuxième concentration de matière étant supérieure à la première concentration de matière. Dans certains exemples, le module de récupération est destiné à récupérer une matière volatile liquide à partir d'un gaz qui a traversé le filtre.
PCT/US2022/030728 2022-05-24 2022-05-24 Filtres à matière volatile WO2023229583A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2022/030728 WO2023229583A1 (fr) 2022-05-24 2022-05-24 Filtres à matière volatile

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2022/030728 WO2023229583A1 (fr) 2022-05-24 2022-05-24 Filtres à matière volatile

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1948779A (en) * 1931-06-30 1934-02-27 Chester F Hockley Adsorption system
US3534529A (en) * 1969-10-27 1970-10-20 Day & Zimmermann Inc Process for recovering organic vapors from airstream
US4414003A (en) * 1980-11-07 1983-11-08 Lohmann Gmbh & Co., Kg Process and apparatus for the recovery of solvents
US5759236A (en) * 1993-11-22 1998-06-02 Engelhard Process Chemicals Gmbh Energy-saving process for the separation of organic compounds from gases

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1948779A (en) * 1931-06-30 1934-02-27 Chester F Hockley Adsorption system
US3534529A (en) * 1969-10-27 1970-10-20 Day & Zimmermann Inc Process for recovering organic vapors from airstream
US4414003A (en) * 1980-11-07 1983-11-08 Lohmann Gmbh & Co., Kg Process and apparatus for the recovery of solvents
US5759236A (en) * 1993-11-22 1998-06-02 Engelhard Process Chemicals Gmbh Energy-saving process for the separation of organic compounds from gases

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