Plasma generating device and electrostatic sprayer for generating plasma activated mist

Abstract

The invention provides a plasma generating device and an electrostatic sprayer for generating plasma activated mist. The device comprises: a shell, one end of which is connected to a nozzle, and a plasma generator is arranged in the shell; the plasma generator is a flat dielectric barrier discharge structure; the plasma generator comprises a dielectric layer, a ground electrode and a high-voltage electrode, and the ground electrode faces one side of the nozzle; the plasma generator is provided with a through hole, and the through hole passes through the ground electrode, the dielectric layer and the high-voltage electrode in sequence; the ground electrode is a fan blade structure, and the ground electrode is connected to a rotating shaft of a motor, and the rotating shaft passes through the through hole.

Description

Technical Field

[0001] The invention belongs to the technical field of plasma application, and in particular relates to a plasma generating device and an electrostatic sprayer. Background Art

[0002] Plasma is an ionized gaseous substance composed of positive and negative ions produced by the ionization of atoms and atomic groups that have been deprived of some electrons. It is a macroscopic electrically neutral ionized gas with a scale larger than the Debye length. Plasma produces reactive chemicals, rich in a large number of active free radicals, neutral particles, oxygen ions, hydroxyl and other active particles (RONS), such as hydroxyl radicals (OH), nitrous oxide (N2O), nitric oxide (NO), ozone (O3), and superoxide (O2).

[0003] Plasma is an ionized gas composed of a collection of ions, electrons and neutron particles. It is the fourth state of matter besides solid, liquid and gas. It is electrically neutral as a whole, has excellent broad-spectrum bactericidal properties, and can directly act on the surface of biological tissues.

[0004] When low-temperature plasma interacts with aqueous solution, a variety of active oxygen free radicals and active nitrogen free radicals will be generated. The free radicals make the plasma-activated aqueous solution have a higher redox potential and show a strong oxidizing ability. Plasma-activated water (PAW) can be prepared by the contact reaction between plasma and aqueous medium. Using plasma to prepare plasma-activated water can convert a variety of RONS in the gas phase into long-lived ions, free radicals and active components in the liquid phase, overcoming the limitation that active particles in plasma dissipate quickly.

[0005] Plasma activated water is an aqueous solution rich in active oxygen components obtained by low-temperature plasma discharge treatment at atmospheric pressure in water or on the surface of water. Plasma activated water is used as an intermediate medium to indirectly sterilize items, which has a good killing effect on a variety of pathogens, and the solution treatment has good uniformity and fluidity. Summary of the invention

[0006] In order to overcome the above problems existing in the prior art, the present invention provides a plasma generating device for improving the atomization performance of plasma activated water.

[0007] The present application provides a plasma generating device, the device comprising: a shell, one end of which is connected to a nozzle, a plasma generator being arranged in the shell; the plasma generator being a flat dielectric barrier discharge structure; the plasma generator comprising a dielectric layer, a ground electrode and a high-voltage electrode, the ground electrode facing one side of the nozzle; the plasma generator being provided with a through hole, the through hole sequentially penetrating the ground electrode, the dielectric layer and the high-voltage electrode; the ground electrode being a fan blade structure, the ground electrode being connected to a rotating shaft of a motor, the rotating shaft passing through the through hole.

[0008] In one embodiment, the rotating shaft of the motor is connected to the ground terminal through a conductive slip ring. Here, the conductive slip ring is a device used to provide power and signal transmission for a device with a fixed position and a device with a rotating position.

[0009] In the above scheme, the ground electrode of the fan blade structure can form an airflow during the rotation process, and the airflow can diffuse the plasma activated gas into the atomization chamber. The fan blade-shaped electrode can stir the gas in the cavity during the rotation process, and the stirring process can break down the unactivated gas to generate more plasma activated gas.

[0010] In one embodiment, the plasma generator is disc-shaped; the plasma generator includes a disc surface and an outer contour surface; the outer contour surface of the plasma generator and the inner wall of the shell form a clearance fit; the through hole and the airflow channel in the nozzle are coaxial.

[0011] In one embodiment, the minimum distance d between the surface of one side of the ground electrode and the dielectric layer is less than a preset value d0. Here, d0 may be a maximum breakdown distance when plasma discharge is generated.

[0012] In one embodiment, the liquid inlet of the spray head is connected to a water tank.

[0013] The present application provides an electrostatic sprayer, comprising the above-mentioned plasma generating device, wherein a high-voltage electrostatic generator is arranged in the atomization chamber; the high-voltage electrostatic generator is in a ring structure, and the high-voltage electrostatic generator is located between the nozzle and the liquid inlet.

[0014] In the above scheme, the outer surface of the high-voltage electrostatic generator and the inner surface of the air outlet of the atomizing chamber form a gap fit. When the equipment is working, the high-voltage electrostatic generator and the atomizing chamber are equivalent to connecting a high-voltage power supply. According to the principle of inductive charging, the mist plasma in the atomizing chamber will be positively charged and ejected from the nozzle under the action of the electric field force and airflow. They repel each other during the directional movement to form small and evenly distributed droplets, which are evenly adsorbed on the surface of the object.

[0015] The present application provides an electrostatic sprayer, the device comprising a shell, one end of the shell is connected to a nozzle, a plasma generator is arranged in the shell; the plasma generator is a flat dielectric barrier discharge structure; the plasma generator comprises: a quartz tube, a ground electrode and a high-voltage electrode; the quartz tube is fixed in the shell by a positioning piece; the air outlet of the quartz tube is connected to an atomization chamber; the ground electrode is coated on the outer surface of the quartz tube, and the high-voltage electrode is placed in the quartz tube.

[0016] In one embodiment, one end of the quartz tube facing the atomization chamber has a conical opening structure.

[0017] In one embodiment, the air inlet of the quartz tube is connected to an air supply mechanism or a booster pump, and the liquid inlet of the atomization chamber is connected to a water tank.

[0018] In one embodiment, the high voltage electrode comprises a spiral structure portion and a needle tip portion, wherein the spiral structure portion is disposed in a quartz tube, and the needle tip portion extends into the atomization chamber.

[0019] (1) The plasma generating device provided by the present invention can form an airflow during the rotation of the blade-shaped electrode, and the airflow can diffuse the plasma-activated gas into the atomization chamber. The blade-shaped electrode can stir the gas in the cavity during the rotation, and the stirring process can break down the unactivated gas to generate more plasma-activated gas.

[0020] (2) The electrostatic sprayer provided by the present invention increases a high-voltage electric field in the nozzle part to increase the distance of the plasma jet. Under the dual effects of the high-pressure airflow and the high-voltage electric field, the plasma jet distance is farther and the generation efficiency is higher.

[0021] (3) The electrostatic sprayer provided by the present invention forms droplets of plasma-activated solution with the same charge, which repel each other during directional movement to form fine and evenly distributed droplets. The droplets are evenly adsorbed on the surface of the object, which can improve the atomization performance of plasma-activated water and is suitable for disinfection and cleaning of irregular object surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A structural diagram of an embodiment of a plasma generating device provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of a dielectric barrier discharge structure provided in an embodiment of the present application;

[0024] Figure 3 A structural diagram of an embodiment of an electrostatic sprayer provided in an embodiment of the present application;

[0025] Figure 4A structural diagram of another embodiment of the electrostatic sprayer provided in the embodiment of the present application;

[0026] Figure 5 A structural diagram of another embodiment of the electrostatic sprayer provided in the embodiment of the present application;

[0027] Figure 6 Provided for the embodiments of this application Figure 5 A schematic diagram of the structure in another direction;

[0028] Figure 7 Provided for the embodiments of this application Figure 5 Schematic diagram of a plasma generator;

[0029] Figure 8 Provided for the embodiments of this application Figure 5 Schematic diagram of the nozzle in .

[0030] Among them: 1. Shell; 2. Nozzle; 3. Dielectric layer; 4. Ground electrode; 5. High-voltage electrode; 6. Atomization chamber; 7. Liquid inlet; 8. Handle; 9. Water tank; 10. High-voltage electrostatic generator; 11. Quartz tube; 12. Positioning piece; 13. Booster pump. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention.

[0032] In the related art, when the electrostatic sprayer generates electrostatic spray, the aqueous solution is not subjected to plasma activation treatment. Therefore, the solution of the droplets does not contain active particles (RONS) such as active free radicals, neutral particles, oxygen ions, and hydroxyls, making it difficult to use plasma-activated water as an intermediate medium to indirectly sterilize objects.

[0033] When the existing plasma generator generates plasma activated water, the dielectric barrier discharge device generates plasma active substances, which are introduced into the water through zeolite. However, the plasma activated water is not atomized. When the plasma activated water does not form an electrostatic spray, it cannot be uniformly attached to the surface of irregular objects under the action of electrostatics.

[0034] The present application provides a plasma generating device, which includes: a shell 1, one end of which is connected to a nozzle 2, and a plasma generator is arranged in the shell 1; the plasma generator is a flat dielectric barrier discharge structure; the plasma generator includes a dielectric layer 3, a ground electrode 4 and a high-voltage electrode 5, and the ground electrode 4 faces one side of the nozzle 2; the plasma generator is provided with a through hole, and the through hole passes through the ground electrode 4, the dielectric layer 3 and the high-voltage electrode 5 in sequence; the ground electrode 4 is a fan blade structure, and the ground electrode 4 is connected to the rotating shaft of the motor, and the rotating shaft passes through the through hole.

[0035] In one embodiment, the rotating shaft of the motor is connected to the ground terminal through a conductive slip ring. Here, the conductive slip ring is a device used to provide power and signal transmission for a device with a fixed position and a device with a rotating position.

[0036] In the above scheme, the ground electrode of the fan blade structure can form an airflow during the rotation process, and the airflow can diffuse the plasma activated gas into the atomization chamber. The fan blade-shaped electrode can stir the gas in the cavity during the rotation process, and the stirring process can break down the unactivated gas to generate more plasma activated gas.

[0037] In one embodiment, the plasma generator is disc-shaped; the plasma generator includes a disc surface and an outer contour surface; the outer contour surface of the plasma generator and the inner wall of the shell form a clearance fit; the through hole and the air flow channel in the nozzle 2 are coaxial.

[0038] In one embodiment, the nozzle 2 includes an atomizing chamber 6 and a nozzle; the atomizing chamber is connected to the shell 1, and the connecting portion between the atomizing chamber and the shell 1 is a trumpet-shaped cavity; a contraction port is formed on one side of the trumpet-shaped cavity close to the atomizing chamber; an atomizing chamber 6 is arranged between the contraction port and the nozzle, and a liquid inlet 7 is arranged on the side wall of the atomizing chamber 6.

[0039] In one embodiment, the minimum distance d between one side surface of the ground electrode and the dielectric layer is less than a preset value d0. Here, d0 may be a maximum breakdown distance when plasma discharge is generated.

[0040] In one embodiment, the liquid inlet 8 of the spray head is connected to the water tank 9 .

[0041] The present application provides an electrostatic sprayer, including the above-mentioned plasma generating device, wherein a high-voltage electrostatic generator 10 is arranged in an atomization chamber 6; the high-voltage electrostatic generator 10 is annular in structure, and the high-voltage electrostatic generator 10 is located between the nozzle and the liquid inlet 7.

[0042] In the above scheme, the outer surface of the high-voltage electrostatic generator and the inner surface of the air outlet of the atomizing chamber form a gap fit. When the equipment is working, the high-voltage electrostatic generator and the atomizing chamber are equivalent to connecting a high-voltage power supply. According to the principle of inductive charging, the mist plasma in the atomizing chamber will be positively charged and ejected from the nozzle under the action of the electric field force and airflow. They repel each other during the directional movement to form small and evenly distributed droplets, which are evenly adsorbed on the surface of the object.

[0043] The present application provides an electrostatic sprayer, which includes a shell 1, one end of which is connected to a nozzle 2, and a plasma generator is arranged in the shell 1; the plasma generator is a flat dielectric barrier discharge structure; the plasma generator includes: a quartz tube 11, a ground electrode 4 and a high-voltage electrode 5; the quartz tube 11 is fixed in the shell 1 by a positioning member 12; the air outlet of the quartz tube 11 is connected to an atomization chamber 6; the ground electrode 4 is coated on the outer surface of the quartz tube 11, and the high-voltage electrode 5 is placed in the quartz tube 11.

[0044] In one embodiment, one end of the quartz tube 11 facing the atomization chamber 6 has a conical opening structure.

[0045] In one embodiment, the air inlet of the quartz tube 11 is connected to an air supply mechanism or a booster pump 13 , and the liquid inlet 7 of the atomization chamber 6 is connected to a water tank 9 .

[0046] In one embodiment, the high voltage electrode 5 includes a spiral structure portion and a needle tip portion, the spiral structure portion is disposed in the quartz tube 11 , and the needle tip portion extends to the atomization chamber 6 .

[0047] See also Figure 1 and Figure 2 A plasma generating device comprises a shell 1, one end of which is connected to a nozzle 2, a columnar cavity is arranged in the shell 1, a dielectric layer 3 is arranged in the columnar cavity, a ground electrode 4 and a high-voltage electrode 5 are arranged on both sides of the dielectric layer 3, and the ground electrode 4 is located on the side close to the nozzle 2; the dielectric layer 3 and the high-voltage electrode 5 are both disc structures, the two disc structures are arranged on the radial section of the columnar cavity, and the centers of the dielectric layer 3 and the high-voltage electrode 5 are provided with through holes; the ground electrode 4 is a fan blade structure, the ground electrode 4 is connected to a rotating shaft, the rotating shaft passes through the through hole, and the rotating shaft drives the ground electrode 4 to rotate.

[0048] In the example, both ends of the nozzle 2 are trumpet-shaped cavities, one of which is connected to the columnar cavity of the shell 1, and the other is a nozzle; a channel is provided between the two trumpet-shaped cavities, which is the atomization chamber 6, and a liquid inlet 7 is provided on the side wall of the channel.

[0049] In one embodiment, a motor is provided in the housing 1, the motor is located on one side of the high voltage electrode, and the motor drives the ground electrode 4 to rotate. The motor shaft is perpendicular to the plane where the ground electrode is located, and the motor shaft is coaxial with the axis of the air flow channel. The liquid inlet 7 of the nozzle 2 is connected to the water tank 9.

[0050] In the example, the fan blade-shaped electrode can form an airflow during the rotation process, and the airflow can diffuse the plasma-activated gas to the atomization chamber. The fan blade-shaped electrode can stir the gas in the cavity during the rotation process, and the stirring process can break down the unactivated gas to produce more plasma-activated gas. The airflow in the atomization chamber is accelerated and the air pressure is reduced, forming a negative pressure at the liquid inlet 7. The water in the water tank 9 enters the atomization chamber from the liquid inlet 7 in the form of mist through the conduit, and combines with the plasma to form a plasma-activated mist plasma.

[0051] In one embodiment, a handle 8 is connected to the end of the housing 1 away from the spray head 2 for easy holding by an operator.

[0052] In one embodiment, the minimum distance d between one side surface of the ground electrode 4 and the dielectric layer 3 is less than a preset value d0, where d0 is the maximum breakdown distance when plasma discharge is generated.

[0053] The present disclosure provides an electrostatic sprayer. Figure 3 , including the above-mentioned plasma generating device, a high-voltage electrostatic generator 10 is arranged in the atomization chamber 6, the high-voltage electrostatic generator 10 is a ring-shaped structure, and the high-voltage electrostatic generator 10 is located between the nozzle and the liquid inlet 7.

[0054] In the example, the outer surface of the high-voltage electrostatic generator and the inner surface of the air outlet of the atomization chamber form a gap fit. When the electrostatic sprayer is working, the high-voltage electrostatic generator and the atomization chamber are equivalent to connecting a high-voltage power supply. According to the principle of inductive charging, the mist plasma in the atomization chamber will be positively charged and ejected from the nozzle under the action of the electric field force and airflow. They repel each other during the directional movement to form small and evenly distributed droplets, which are evenly adsorbed on the surface of the object.

[0055] The present disclosure provides an electrostatic sprayer. Figure 4 , comprising a shell 1, one end of which is connected to a nozzle 2, a columnar cavity is provided in the shell 1, and both ends of the nozzle 2 are trumpet-shaped cavities, one of which is connected to the columnar cavity of the shell 1, and the other trumpet-shaped cavity is a nozzle; a channel is provided between the two trumpet-shaped cavities, which is an atomization chamber 6, and a liquid inlet 7 is provided on the side wall of the channel.

[0056] In the example, a quartz tube 11 is arranged in the columnar cavity, and the quartz tube 11 is fixed in the columnar cavity by a disc-shaped positioning member 12, and a positioning hole is arranged at the center of the disc-shaped positioning member. The quartz tube 11 passes through the positioning hole arranged at the center of the disc-shaped positioning member, and the outer surface of the quartz tube 11 and the inner surface of the positioning hole form a clearance fit.

[0057] In the example, one end of the quartz tube 11 is connected to the atomizing chamber 6, and the other end is an air inlet, which is connected to the columnar cavity; the quartz tube 11 serves as a dielectric barrier, the ground electrode 4 is coated on the outer surface of the quartz tube 11, and the high-voltage electrode 5 is placed inside the quartz tube 11; the high-voltage electrode 5 includes a spiral structure part and a needle tip part, the spiral structure part is arranged in the quartz tube 11, and the needle tip part extends into the atomizing chamber 6. The air inlet of the quartz tube 11 is connected to the air supply mechanism or the booster pump 13, and the liquid inlet 7 of the atomizing chamber 6 is connected to the water tank 9.

[0058] In the example, the high voltage electrode, dielectric barrier layer, and ground electrode constitute a dielectric barrier discharge structure, and the quartz tube dielectric barrier layer. In the dielectric barrier discharge structure, the high voltage electrode and the ground electrode are separated by an insulating dielectric. When a high voltage pulse is applied between the high voltage electrode and the ground electrode, the gas between the high voltage electrode and the quartz tube will be broken down to form a low temperature plasma.

[0059] In one embodiment, the diameter of the quartz tube 11 gradually decreases at one end facing the atomization chamber 6, presenting a conical opening structure. A handle 8 is connected to the end of the housing 1 away from the spray head 2.

[0060] In the related art, electrostatic sprayers usually use a high-voltage DC power supply to electrostatically charge water mist in the form of contact charging, induction charging, etc., while the present invention uses a unipolar positive pulse AC power supply to charge water mist, with an integrated air-water circuit design; the high-voltage electrode of the present invention has a spiral part that generates plasma, and a needle-shaped tip that charges the water mist to make it charged.

[0061] See also Figure 4 An air flow channel is formed inside the quartz tube. When the air supply mechanism or the booster pump delivers gas to the quartz tube, the high-speed air flow forms a low pressure in the atomization chamber and a negative pressure in the water injection hole. The water in the water storage chamber enters the atomization chamber through the water injection hole in the form of mist, and combines with the plasma to form a plasma-activated mist, which can pressurize the cavity in the quartz tube and form an air flow in the atomization chamber.

[0062] In the example, when the airflow passes through the atomization chamber, the liquid in the water tank is sucked into the atomization chamber through the liquid inlet under the action of negative pressure. The high-speed airflow produces atomization on the water droplets injected into the atomization chamber under the Bernoulli effect. The Bernoulli effect is applicable to stable, non-viscous, incompressible flow along a streamline. In the same fluid, the higher the flow rate, the lower the pressure; the lower the flow rate, the higher the pressure. The fluid will automatically flow from high pressure to low pressure.

[0063] In the example, when the electrostatic sprayer is working, the tip of the high-voltage electrode extends to the atomization chamber, so that the high-voltage electrode and the atomization chamber are equivalent to connecting a high-voltage power supply, and the tip of the high-voltage electrode is equivalent to a high-voltage electrostatic generator. According to the principle of inductive charging, the mist plasma in the atomization chamber will be positively charged and ejected from the nozzle under the action of the electric field force and airflow, repelling each other during the directional movement to form small and evenly distributed droplets, which are evenly adsorbed on the surface of the object.

[0064] The present disclosure provides an electrostatic sprayer. Figures 5 to 8 , which is composed of a plasma generating part, a circuit part, a nozzle part, a power supply part, an air supply part, and a pressurizing part, and specifically includes a plasma generating part 101, in which a plasma generating device is placed; a circuit part 102, in which a plasma power supply circuit board and an air pump circuit board are both placed; a nozzle part 103; a power supply part 104, in which a battery compartment is placed; an air supply part 105, in which an air pump is placed; a conduit 106, connecting the plasma generating device and the nozzle; a conduit 107, connecting the air pump and the plasma generating device; a water tank 108; a metal strip 109; a conduit 1010, connecting the water tank and the nozzle; a high-voltage electrode 1011; a nozzle air inlet 1012; a nozzle water injection hole 1013; a nozzle atomization chamber 1014; and a nozzle 1015.

[0065] The above descriptions are merely embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related system fields, are also included in the protection scope of the present invention.

Claims

1. A plasma generating device, characterized in that: The device comprises: A shell (1), one end of the shell (1) being connected to the nozzle (2), a plasma generator being arranged inside the shell (1); the plasma generator being a flat plate-shaped dielectric barrier discharge structure; The plasma generator comprises a dielectric layer (3), a ground electrode (4) and a high-voltage electrode (5), wherein the ground electrode (4) faces one side of the nozzle (2); The plasma generator is provided with a through hole, the through hole sequentially penetrating the ground electrode (4), the dielectric layer (3) and the high-voltage electrode (5); the ground electrode (4) is a fan blade structure, the ground electrode (4) is connected to the rotating shaft of the motor, and the rotating shaft passes through the through hole; the plasma generator is in the shape of a disk; the plasma generator comprises a disk surface and an outer contour surface; The outer contour surface of the plasma generator and the inner wall of the shell form a clearance fit; the through hole and the air flow channel in the nozzle (2) are coaxial; The minimum distance between a side surface of the ground electrode (4) and the dielectric layer (3) is smaller than a preset value; The preset value is the maximum breakdown distance when plasma discharge is generated.

2. A plasma generating device according to claim 1, characterized in that: The spray head (2) comprises an atomization chamber (6) and a nozzle; the atomization chamber is in communication with the housing (1), and the connection portion between the atomization chamber and the housing (1) is a trumpet-shaped cavity; The trumpet-shaped cavity forms a contraction opening on one side close to the atomization chamber; the atomization chamber (6) is arranged between the contraction opening and the nozzle, and a liquid inlet (7) is arranged on the side wall of the atomization chamber (6).

3. A plasma generating device according to claim 2, characterized in that: The liquid inlet (7) is connected to the water tank (9).

4. An electrostatic sprayer, characterized in that: A plasma generating device comprising any one of claims 1 to 3; A high-voltage electrostatic generator (10) is arranged in the atomization chamber (6); the high-voltage electrostatic generator (10) is in a ring-shaped structure, and the high-voltage electrostatic generator (10) is located between the nozzle and the liquid inlet (7).

5. An electrostatic sprayer, characterized in that: It comprises a shell (1), one end of the shell (1) is connected to a nozzle (2), and a plasma generator is arranged inside the shell (1); the plasma generator is a flat plate-shaped dielectric barrier discharge structure; The plasma generator comprises: a quartz tube (11), a ground electrode (4) and a high-voltage electrode (5); the quartz tube (11) is fixed in the housing (1) via a positioning member (12); The air outlet of the quartz tube (11) is in communication with the atomization chamber (6); the ground electrode (4) is coated on the outer surface of the quartz tube (11), and the high-voltage electrode (5) is placed inside the quartz tube (11); One end of the quartz tube (11) facing the atomization chamber (6) is in a conical opening structure; The air inlet of the quartz tube (11) is connected to an air supply mechanism or a booster pump (13), and the liquid inlet (7) of the atomization chamber (6) is connected to a water tank (9).

6. An electrostatic sprayer according to claim 5, characterized in that: The high-voltage electrode (5) comprises a spiral structure portion and a needle-shaped tip portion, the spiral structure portion is arranged in a quartz tube (11), and the needle-shaped tip portion extends into the atomization chamber (6).

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