Method for supplying air into a spray booth and a ventilation unit for implementing the method

Abstract

Presented are the method of paint booth air feeding to paint with liquid paints (variants) and an air supply unit to realize the method (variants). Said group of innovations consists of two innovations to the method and three innovations to the installation to realize the methods. In the method (variant 1), a closed air stream is created inside the painting booth and air supply unit, after passing the painting zone it is divided into two streams, the first stream returning to the painting booth, while the second stream, containing flammable liquid vapors, is extracted to atmosphere. Simultaneously, some additional air is taken from atmosphere, mixed with return air and supplied to the paint booth painting zone. In the method (variant 2) a closed air stream is created inside the painting booth and air supply unit, and, after passing through the painting zone, is mixed with some additional fresh air and then divided into two streams, the first returning to the painting booth, while the second stream containing flammable liquid vapors, is extracted to atmosphere. The painting booth with separated units of the air supply unit (variants 1 and 2) is intended to realize the method according to claim 1 (FIGS. 1 and 4). The painting booth with connected units of the air supply unit (variants 1 and 2) is intended to realize the method according to claim 1 (FIGS. 2 and 3). The paint booth with air supply unit (variant 3) is intended to realize the method according to claim 2 (FIG. 5). A better performance and improved ecological properties are the immediate technical results of the innovations proposed.

Claims

1. An air supply unit for feeding and extracting air from a painting booth, wherein the air supply unit comprises a return air treatment unit configured to provide an air stream to be returned to the painting booth by the air supply unit at the same time that paint is supplied to an object located in the painting booth to paint the object, the return air treatment unit having a housing and a partition that divides an area defined by said housing into a suction zone, a high pressure zone and a recirculation zone, said partition configured to permit air to flow from said suction zone to said high pressure zone, and configured to permit air to flow directly from said high pressure zone to said recirculation zone and said partition including a solid portion configured to prevent air from flowing directly from said suction zone to said recirculation zone, and an intake unit fluidly connected to the return air treatment unit by a mixing zone, said intake unit including an intake fan to draw air through said intake unit and said intake unit being configured to provide fresh air to said mixing zone at the same time that paint is supplied to an object located in the painting booth to paint the object, said mixing zone being configured for mixing said air stream exiting from the return air treatment unit and fresh air exiting from the intake unit into an airflow for return to the painting booth, an air duct operably connected to the painting booth and said return air treatment unit for transporting all airflow from said painting booth to said suction zone of said return air treatment unit and an air duct operably connected to the mixing zone and the painting booth for returning said airflow to the painting booth, one or more filters located between said high pressure zone and said recirculation zone so that air flowing from the high pressure zone to the recirculation zone passes through said one or more filters; an air regulation unit operably connected to the high pressure zone to extract air from said high pressure zone of said return air treatment unit, a second air regulation unit operably connected to the intake unit to take in fresh air for supply to said intake unit, and a recirculation fan and a recirculation fan housing are attached to the partition and are located to create suction in said suction zone of said return air treatment unit and high pressure in said high pressure zone of said return air treatment unit sufficient to ensure that a portion of air in the high pressure zone is fed to the recirculation zone, and wherein said mixing zone is located either in the painting booth between the return air treatment unit and the intake unit, or inside a special compartment connected to exits of the recirculation zone of the return air treatment unit and the intake unit, and wherein recirculating air leaves the return air treatment unit via the recirculating zone and flows 1 the mixing zone.

2. The air supply unit of claim 1, wherein there is only one recirculation fan and only one intake fan.

3. The air supply unit of claim 1, wherein the return air treatment unit is a single chamber divided by the partition.

4. The air supply unit of claim 1, wherein the partition divides the return air recirculation unit into a suction compartment enclosing the suction zone, a high pressure compartment enclosing the high pressure zone and an air recirculation compartment enclosing the air recirculation zone.

5. The air supply unit of claim 1, wherein the partition is substantially T-shaped.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a painting booth with ASU having two groups of fans and separated units, general view, variant 1.

(2) FIG. 2 is a painting booth with ASU having two groups of fans and combined units, general view, variant 1.

(3) FIG. 3 is a painting booth with ASU having two groups of fans and combined units, general view, variant 2.

(4) FIG. 4 is a painting booth with ASU having two groups of fans and separated units, general view, variant 2.

(5) FIG. 5 is a painting booth with ASU having one group of fans, general view, variant 3.

(6) FIG. 6 is a front view of the portion of the partition 21 of FIG. 4 located between the high pressure zone 11 and the recirculation zone 23 showing the filter 24 located within partition 21.

DESCRIPTION OF EMBODIMENTS

(7) The painting booth with separated units of ASU (Variants 1 and 2 of the method according to claim 1, FIGS. 1 and 4) comprises body 1 with filters 2. Filters 2 divide the painting booth into three zones: zone 3 to mix streams of return (recirculated) air and fresh atmosphere air, zone 4 to paint objects (working zone) where the mixed air stream is supplied from zone 3, and zone 5 to extract used air contaminated with EFL vapors and paint's residue particles. Body 1 of the painting booth is connected by means of supply ducts 6 and extract ducts 7 with ASU which consists of two main units: unit 8 for return air treatment and intake unit 9.

(8) The painting booth with combined units of ASU (Variants 1 and 2 of the method according to claim 1, FIGS. 2 and 3) comprises body 1 with filters 2. Filters 2 divide the painting booth into three zones: zone 20 to supply air, zone 4 to paint objects (working zone), and zone 5 to extract used air contaminated with EFL vapors and paint's residue particles. Body 1 of the painting booth is connected by means of supply duct 6 and extract duct 7 with ASU which consists of two main units: unit 8 for return air treatment and intake unit 9.

(9) Unit 8 of ASU (Variant 1 of the method according to claim 1, FIGS. 1 and 2) comprises recirculation fan 10 which creates a closed air stream as well as pressure zone 11 designed to divide used air into two streams, the first returning to the painting zone and creating a closed air stream inside the painting booth and ASU, while the second (with EFL vapors) is extracted to atmosphere by means of ARU 12.

(10) Intake unit 9 comprises intake fan 13 which divides the internal volume of unit 9 into zone 14 responsible for suction and cleaning the fresh air with filters 15 and pressure zone 16, air heater unit 17 being placed either in pressure zone 16 or in suction and cleaning zone 14. Intake unit 9 consists of ARU 18, which provides for the required volume of fresh air. ARU 18 and 12 are coordinated to maintain the necessary air pressure inside body 1 of the painting booth.

(11) Unit 8 of ASU (Variant 2 of the method according to claim 1, FIGS. 3 and 4) comprises recirculation fan 10 to create a closed air stream and partition 21 which divides the internal volume of unit 8 into three zones: suction zone 22, pressure zone 11 and zone 23 to clean or recirculate return air, and zone 3 to mix air streams, connected with the painting booth by means of supply air duct 6. Pressure zone 11 is intended to divide the used air into streams, the first returning to the painting zone which creates a closed air stream inside the painting booth and ASU while the second stream (with EFL vapors) is extracted to atmosphere by means of ARU 12.

(12) Partition 21 consists of two parts, the lower being air proof, the upper having holes for air which goes from pressure zone 11 to cleaning of return air zone 23 where return air is cleaned by filters 24. Filters 24 may be fitted either at the boundary between zones 11 and 23 into the holes of partition 21 or into supply air duct 6, zones 11 and 23 becoming one zone in this case.

(13) Zone 23, where return air is cleaned, is connected with air stream mixing zone 3, the latter being connected with intake unit 9 comprising intake fan 13 which divides unit 9 into zone 14, where fresh air is sucked and cleaned by filters 15, and pressure zone 16, with air heater unit 17 being placed either in pressure zone 16 or in suction and cleaning zone 14.

(14) Intake unit 9 also comprises ARU 18 which supplies the required volume of fresh air. ARU 18 and 12 are coordinated to maintain the required air pressure inside body 1 of the painting booth.

(15) ASU (Variants 1 and 2) can work either in the “Paint” or “Baking” mode. By-pass ARU 19 is fitted either in suction zone 22 of unit 8 (FIG. 3) or in suction zone 14 of unit 9 (FIGS. 1, 2 and 4) to operate in the “Baking” mode.

(16) The painting booth (Variant 3 to realize the method according to claim 2) comprises body 1 with filters 2. Filters 2 divide the painting booth into three zones: zone 20 to supply air, zone 4 to paint objects (working zone), and zone 5 to extract used air contaminated with EFL vapors and paint's residue particles. Body 1 of the painting booth is connected by means of supply duct 6 and extract duct 7 with ASU which consists of two main units: unit 8 for return air treatment and intake unit 9.

(17) Unit 8 of ASU comprises recirculation fan 10 to create a closed air stream and, simultaneously, to suck in fresh air, partition 21 which divides the internal volume of unit 8 into three zones: zone 3 to mix the air streams, pressure zone 11 and zone 23 to clean or recirculate return air. Zone 3 is intended to mix streams of used and fresh air, while pressure zone 11 is intended to divide air into two streams, the first returning to the painting zone which creates a closed air stream inside the painting booth and ASU, the second stream with EFL vapors being extracted to atmosphere by ARU 12.

(18) ARU 25 is fitted into zone 3 to regulate (together with ARU 18 at the intake of unit 9) the proportion of used and fresh air streams supplied by the fan. Partition 21 consists of two parts: the lower is air proof, while the upper is made with holes for air coming from pressure zone 11 to return air cleaning zone 23 where the return air is cleaned by filters 24. Filters 24 can be placed either at the boundary between zones 11 and 23 in the holes of partition 21 or in supply air duct 6, or combined with filters 2 in the supply air zone, zones 11 and 23 being coupled in this case.

(19) Zone 3 is connected with intake unit 9 comprising filters 15 and heater unit 17.

(20) ARU 18 and 12 are coordinated to maintain the required air pressure inside body 1 of the painting booth.

(21) ASU can be operated either in the “Paint” or “Baking” mode. Bypass ARU 19 is provided in fresh air intake unit 9 before heater unit 17 to operate in the “Baking” mode.

MODES FOR CARRYING OUT THE INVENTION

(22) The method of paint booth air feeding to paint with liquid paints (variant 1) can be realized as follows.

(23) To work in the “Paint” mode, the object to be painted is placed in body 1 of the paint booth (zone 4). Both recirculation 10 and intake 13 fans start working simultaneously when ASU is turned on. Some finely dispersed paint particles and EFL vapors, which are trapped in the air stream, are formed in zone 4 when the object is painted. The air stream, due to negative pressure created by fan 10, goes through bottom filters 2 of the booth's body, where paint particles are partially arrested, and then part of the air stream containing EFL vapors and finely dispersed dry paint particles is extracted through ARU 12 to be cleaned and/or exhausted to atmosphere, but the main air stream goes to mix with fresh external air supplied by the intake fan into zone 3, which leads to a decreased EFL vapor concentration and further removal of dust and paint in upper filters 2 of the booth's body. After the filters, the uniform mixed air stream is again supplied to the whole area of working zone 4.

(24) The second stream containing EFL vapors is either cleaned of EFL vapors by sorption or burning, or is directly exhausted to atmosphere.

(25) The method of paint booth air feeding to paint with liquid paints (variant 2) is realized as follows.

(26) To work in the “Paint” mode, the object to be painted is placed in body 1 of the paint booth (zone 4). Fan 10 creates negative pressure in zone 3, which leads to suction of fresh air from atmosphere. This air is cleaned of dust in filter 15 and then goes through heater unit 17 to stream mixing zone 3. The volume of fresh air intake is determined by opening of ARU 18. Recirculation fan 10, due to negative pressure in zone 3, also creates negative pressure in zone 5 whereby air is sucked from the working zone inside the painting booth through paint particle cleaning filters 2. The used air from zone 5 goes through ARU 25 to zone 3 where it mixes with the fresh air stream. The mixed stream is then supplied by fan 10 to zone 11, where it is separated into 2 streams. The first stream, due to pressure of fan 10, goes through filters 24 which can be fitted into holes in partition 21, proceeds through the air duct to the booth's body, where, as it passes through filters 2, it is again supplied as a uniform stream to the whole area of working zone 4 of the booth. The volume of air creating the second stream is determined by ARU 12 opening and is regulated by the operator depending on the amount of excess pressure required in working zone 4 of the painting booth, i.e. a little less than the volume of fresh air supplied.

(27) The second stream containing EFL vapors is either cleaned of EFL vapors by sorption or burning, or is directly exhausted to atmosphere.

(28) The Air Supply Unit to supply and extract air from the booth (variant 1) works as follows.

(29) To work in the “Paint” mode, the object to be painted is placed in body 1 of the paint booth (zone 4). Intake fan 13 creates negative pressure in zone 14 and sucks in fresh air which is cleaned of dust by filter 15 and is then supplied through heater 17 to stream mixing zone 3. The volume of fresh air sucked in is determined by opening of ARU 18. Recirculation fan 10 creates negative pressure in zone 5, whereby air is sucked (extracted) from working zone 4 inside the paint booth by paint particle filters 2. Then, the air is supplied by fan 10 to zone 11, where it is divided into 2 streams. The first stream, cleaned by additional filters (if available) or not cleaned, goes to zone 3 because of pressure of fan 10, where it is mixed with fresh air also supplied under pressure by fan 13 and, when passing through filters 2, is again supplied as a uniform stream to the whole area of working zone 4 of the booth. The volume of air creating the second stream which is exhausted into the cleaning device or atmosphere is determined by ARU 12 opening and is regulated by the operator dependending on how much excess pressure is required in working zone 4 of the painting booth, i.e. a little less than the volume of fresh air supplied.

(30) The Air Supply Unit to supply and extract air from the booth (variant 2) works as follows.

(31) To work in the “Paint” mode, the object to be painted is placed in body 1 of the paint booth (zone 4). Both recirculation 10 and intake 13 fans start working simultaneously when ASU is turned on. Some finely dispersed paint particles and EFL vapors, which are trapped in the air stream, are formed in zone 4 when the object is painted. The air stream, due to negative pressure created by fan 10, goes through bottom filters 2 of the booth's body, where paint particles are partially arrested, and then part of the air stream containing EFL vapors and finely dispersed dry paint particles is extracted through ARU 12 to be cleaned and/or exhausted to atmosphere, while the main air stream goes to fine cleaning filters 24 where additional extraction of finely dispersed paint particles from the return air stream is carried out, and then mixes with fresh external air in zone 3, which leads to a decreased EFL vapor concentration, and finally is further cleaned of dust and paint in upper filters 2. After the filters, the uniform mixed air stream is again supplied to the whole area of working zone 4.

(32) In said variant, internal partition 21 allows additional filters of fine cleaning 24 to be placed in return air treatment unit, which significantly improves the degree of air cleaning compared with variant 1 and lengthens the lifetime of upper filters 2 in the painting booth.

(33) The “Baking” mode (variants 1 and 2) is carried out as follows: the operator opens by-pass ARU 19 and closes ARU 12 and 18 after finishing the painting process. The level of mutual closing of the last two is determined by necessity to maintain some excess pressure in the paint booth body. Fan 13 starts to work in recirculation mode after completing the above steps, sucking air from zone 5 and supplying it through air heater unit 17 to zone 3, which provides fast air heating to the temperature required.

(34) The Air Supply Unit to supply air to the painting booth (variant 3) works as follows.

(35) To work in the “Paint” mode, the object to be painted is placed in body 1 of the paint booth (zone 4). The main (recirculation) fan 10 starts working when ASU is turned on. Fan 10 creates negative pressure in mixing zone 3 and, through it, in intake unit 9, whereby fresh air is sucked from atmosphere and is cleaned of dust by filter 15. It then goes through heater unit 17 to stream mixing zone 3. The volume of fresh air sucked in is determined by opening of ARU 18. Recirculation fan 10 (through zone 3) also creates negative pressure in zone 5 so that air is sucked (extracted) from working zone 4 inside the painting booth through paint particle cleaning filters 2. Used air goes to zone 3 through air duct 7 and ARU 25, where it is mixed with a fresh air stream. The stream ratio is regulated by the degree of mutual opening of ARUs 18 and 25. Then, the mixed air stream is supplied by fan 10 to zone 11, where it is separated into 2 streams. The first stream, due to pressure of fan 10, passes through filters 24 installed in partition 21 and goes to zone 23, then, through air duct 6, to zone 20 of the booth, where, after passing through cleaning filters 2 under pressure of fan 10, it is again supplied as a uniform stream to the whole area of working zone 4 of the booth. The volume of air creating the second stream is determined by ARU 12 opening and is regulated by the operator depending on the amount of excess pressure required in working zone 4 of the painting booth, i.e. a little less than the volume of fresh air supplied.

(36) The “Baking” mode goes as follows: the operator opens by-pass ARU 19 and closes ARUs 12 and 18 after finishing the painting process. The level of mutual closing of the last two is determined by necessity to maintain some excess pressure in the paint booth body. ARU 25 is partly closed to increase the volume of air going through the air heater. Fan 10 starts operating in a full recirculating mode after completing the above steps: it sucks air from zone 5 and supplies it through air heater unit 17 to zone 4 of the booth, which provides fast air heating to the temperature required.

INDUSTRIAL APPLICABILITY

(37) Application of the group of innovations proposed leads to:

(38) a) lower investment costs because of a simplified engineering design of the air units;

(39) b) improvement of exploitation properties because of a lower energy consumption when moving and heating the air;

(40) c) improved ecological properties because less atmospheric air is consumed and its subsequent complete cleaning before exhaust to atmosphere is facilitated.

CITED DOCUMENTS

See Page 1

(41) [1]—U.S. Pat. No. 5,395,285, B05B15/12, 1995 Mar. 7. [2]—German patent DE3408087, B05B15/12, 1985 Sep. 5.