CN112934023A - System and method for generating oxidizing bubbles in a fluid - Google Patents

Abstract

A system for generating oxidizing bubbles in a fluid, comprising a fluid inlet tube; a venturi tube, an assembly with micro-pores or micro-gaps for delivering a medium with oxidizing properties into a fluid; a chamber surrounding the micro-pores or micro-gaps, which can form a swirling flow to increase a contact time between a reagent having an oxidizing property and a fluid and can generate oxidizing bubbles in the fluid; and the fluid outlet pipe is used for discharging the oxidation bubbles in the fluid. The system is capable of generating oxidizing bubbles having a bubble diameter of less than 500 nm.

Description

System and method for generating oxidizing bubbles in a fluid

This application claims priority from U.S. provisional application No. 62/390,017 filed on 2016, 3, 16, under the paris convention, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates generally to a method of generating oxidizing bubbles in a fluid. In particular, the present invention relates to a method of generating oxidizing bubbles in a fluid that have potential applications in disinfection and water treatment.

Background

The following is a list of references cited or intermediate in the specification. The disclosure of each of these references is incorporated herein by reference in its entirety.

[1] U.S. patent No. 7,874,546B2 to j.h.park et al.

[2] U.S. patent No. 8,678,354B2 to w.k.kerfoot et al.

[3] Us patent No. 8,794,604B2 to s.r.ryu.

[4] Li, M.Takahashi, K.Chiba, ozone layer (Chemosphere), 2009, 75 th edition, 1371-1375.

[5] Us hikubo, t.furukawa, r.nakagawa, m.enari, y.makino, y.kawagoe, t.shiina, s.oshita, "Evidence of the presence and Stability of nanobubbles in Water" (evading of the Existence and the Stability of Nano-bubbles in Water), "colloid and surface edition a: physicochemical and Engineering Aspects (Colloids and Surfaces A: physical and Engineering Aspects), 2010, 361 th, pages 31-37.

[6] Agarwal, w.j.ng, y.liu, "Principle and application of micro-and Nanobubble Technology" (principles and Applications of micro-and Nanobubble Technology), "ozone layer" (Chemosphere), 2011, 84 th, page 1175 and 1180.

[7] Marui, "Micro/nanobubbles and Their Applications" Introduction to Micro/Nano-Bubbles and Their Applications, "systematics, Cybernetics and Informatics (Systemics, Cybernetics and Informatics), 2013, 11(4), pages 68-73.

[8] Oshita, t.uchida, "fundamental Characterization of Nanobubbles and Their Potential Applications" (Basic Characterization of Nanobubbles and the theoretical Applications), "biological nanotechnology: a Revolution in dietetics, biomedicine and Health Sciences (Bio-Nanotechnology: A recovery in Food, Biomedical and Health Sciences), first edition, John Willi Ltd, 2013, Chapter 29, page 506-516.

[9] Tsuge, basic principles and Applications of Micro-and Nanobubbles (Micro-and Nanobubbles, fundametal and Applications), Pan Stanford publishing Co., CRC Press, Taylor & Francis publishing group, LCC, 2015.

[10] M. takahashi, "interfacial potential of microbubbles in aqueous solution: the Electrical Properties of Gas-Water Interface (Zeta Potential of Microbubbles in Aqueous Solutions of the Gas-Water Interface), Journal of physicochemical Chemistry, edition B, 2005, No. 109, page 21858-.

[11] S.khuntia, s.k.majumder, p.ghosh, "microbubble assisted water purification and wastewater purification: review "(microbe-aided Water and Water Purification: A Review)," Reviews in Chemical Engineering ", 2012, 28 th (4-6) th, page 191-221 th.

[12] Arumugam, "shallow talking about basic principles of Dynamic microbubble generators for Water treatment and purification Applications" "(throughout the Fundamental Mechanisms of Dynamic Micro-bubble Generator for Water Processing and Cleaning Applications)," Applied Science Master's paper (the Science of Master of Applied Science), in 2015, Torontal mechanical engineering systems.

Water is an essential resource, while the fresh water supply is limited. The growing population increases the demand for fresh water and also results in an increased amount of waste being discharged into the environment, causing more pollution to the clean water source. According to the World Health Organization (WHO) statistics, in 2012, 7.48 million people could not obtain improved drinking water, and 25 million people could not enjoy improved water-based sanitation facilities. It is estimated that the number of deaths per year from diarrhea due to drinking water contamination is 502,000. Therefore, it is highly desirable to develop effective and economical water treatment techniques.

Over the past decade, micro-and nanobubbles have been increasingly studied and applied ([4 ]; [5 ]; [6 ]; [7 ]; [8] and [9 ]). Generally, bubbles having a diameter size of less than 1mm are called microbubbles. Currently, there is no generally accepted classification in terms of size for each type of bubble. Takahashi defines microbubbles as bubbles that are less than 50 microns in diameter and tend to reduce in size and subsequently collapse under water. ([10]).

Khuntia ([11]) and p.arumudam ([12]) describe four basic techniques for generating microbubbles, namely, a spiral fluid flow pattern, a venturi tube type, an ejector type, and a pressure-reducing type. [1] An integrated nanobubble generating device is disclosed, which includes a three-way electronic valve, a pressure tank integrated with components forming part of the system, and a power section that can be selectively adapted to expand the range of use of the system. [2] A generating device is disclosed that includes a housing, a pair of feed ports, a pair of microporous sleeve membranes disposed longitudinally with respect to the housing to generate a fluid flow containing bubbles of less than 10 microns. It is proposed to use a pressure tank and a filter to control the size of the bubbles. However, the use of pressure tanks to generate nanobubbles may result in increased cost or bulky system designs in some applications. [3] A method of generating nanobubbles in a liquid using a bamboo filter without the use of any external mechanical force is disclosed. However, bamboo is a natural material without oxidation resistance. When nanobubbles are created using a strongly oxidizing gas such as ozone, the ozone gas will oxidize and damage the bamboo filter that generates the bubbles.

Disclosure of Invention

It is an object of the present invention to provide a system for generating oxidizing bubbles in a fluid, comprising: a fluid inlet tube; a venturi tube; an assembly having micropores or microgaps of less than about 50 microns for delivering a medium having oxidizing properties into a fluid, wherein the assembly may be a membrane or container attached to the end of one or more tubes through which the medium is injected into the assembly; a chamber surrounding the assembly with a gap of less than or equal to about 0.5mm between a wall of the chamber and the assembly, wherein the chamber is configured to form a swirling flow to increase a contact time between a medium having an oxidizing property and the fluid and to generate oxidizing bubbles in the fluid; a fluid outlet pipe for discharging the oxidizing bubbles in the fluid. It is also an object of the present invention to provide a system and associated method that is capable of producing oxidizing bubbles having a maximum diameter of less than about 500 nm.

Drawings

In order that the invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of a method of generating oxidizing bubbles in a fluid according to an embodiment of the invention;

FIG. 2 shows a schematic diagram of a method of generating oxidizing bubbles in a fluid using a second venturi in accordance with an embodiment of the present invention;

fig. 3 shows a distribution of bubble diameters of a first experiment (experiment 1) according to an embodiment of the present invention;

fig. 4 shows the distribution of bubble diameters of a second experiment (experiment 2) according to an embodiment of the present invention;

fig. 5 shows the distribution of the bubble diameters of the third experiment (experiment 3) according to the embodiment of the present invention; and

fig. 6 shows the absorption spectra of water samples collected at different times when ozone and water containing 0.45ppm methylene blue began to flow.

Detailed Description

In the following description, a system and method of generating oxidizing bubbles are set forth as preferred examples. It will be apparent to those skilled in the art that various modifications, including additions and/or substitutions, may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; the present disclosure, however, is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

According to various embodiments of the present invention, there is provided a system for generating oxidizing bubbles in a fluid, comprising: a fluid inlet tube; a first venturi tube; an assembly having micropores or microgaps of less than about 50 microns for delivering a medium having oxidizing properties into a fluid, wherein the assembly may be a membrane or container attached to the end of one or more tubes through which the medium is injected into the assembly; a chamber surrounding the assembly with a gap of less than or equal to about 0.5mm between a wall of the chamber and the assembly, wherein the chamber forms a vortex to increase contact time between a medium having oxidizing properties and the fluid and to create oxidizing bubbles in the fluid; a fluid outlet pipe for discharging the oxidizing bubbles in the fluid. Optionally, a second venturi is included for varying the bubble diameter of the generated oxidizing bubbles.

Refer to fig. 1. According to one embodiment, the fluid is introduced into the venturi 2 through a fluid inlet tube 1. The fluid introduced from venturi 2 is mixed with the oxidizer delivered from assembly 3 having micro-pores and/or micro-gaps, wherein the assembly may be a membrane or container attached to the end of one or more tubes in which the reagents are injected into assembly 3. The oxidizing bubbles in the fluid formed in the chamber 4 are introduced into a fluid outlet pipe 5 for discharging the oxidizing bubbles in the fluid, the chamber 4 being configured to create a swirling flow of the fluid therein to create a reduced pressure in the flow center core. The swirling flow of the fluid is generated by the fluid inlet pipe 1 creating an accelerated inlet fluid flow as the fluid passes through the throat of the venturi 2 en route to the chamber 4. The fluid inlet tube 1, the venturi tube 2, the assembly 3 with micro-holes and/or micro-gaps, the chamber 4 and the fluid outlet tube 5 are preferably made of a material having oxidation resistance.

In this embodiment, the fluid inlet pipe 1 connected to the venturi pipe 2 forms an accelerated inlet fluid flow when the fluid reaches the chamber 4 through the throat of the venturi pipe 2 on the way, so as to mix the fluid with the medium with oxidizing properties delivered from the assembly 3 with micro-pores and/or micro-gaps. The medium with oxidizing properties is injected into the module 3 through one or more pipes 3a connected to the module 3. The spiral fluid flow formed within the chamber 4 creates a reduced pressure central core such that the oxidizing bubbles on the pore or slit surfaces of the component 3 experience a strong separating force. Thus, oxidizing bubbles having a maximum diameter of less than about 500nm may be produced. The preferred pore size or slit diameter of the pores or microgap of the assembly 3 delivering the medium with oxidizing properties into the chamber 4 is less than about 50 microns, more preferably less than about 10 microns. The preferred clearance between the walls of the chamber 4 and the component 3 is less than or equal to about 0.1mm to 0.5 mm. Its purpose is to assist in creating a swirling flow of fluid.

Preferred media having oxidizing properties comprise at least one oxidizing compound including, but not limited to, air, oxygen, and ozone. Preferably, the fluid may be selected from the group consisting of water, distilled water, deionized water, ultrapure water, aqueous solutions, seawater, wastewater, and oils. And may deliver the fluid flow to the fluid inlet tube 1 by any magnetic or submersible pump. The maximum diameter of the oxidation bubbles produced by the preferred embodiment of the present invention is less than about 500nm, and possibly less than 450nm produced by the more preferred example.

Refer to fig. 2. According to another embodiment, a system for generating oxidizing gas bubbles in a fluid is provided, wherein the bubble diameter of the generated oxidizing gas bubbles is varied by means of the second venturi tube 6. Fluid is directed into the venturi 2 through a fluid inlet tube 1. The fluid introduced from the venturi 2 is mixed with the oxidizer delivered from the assembly 3 having micro-holes and/or micro-gaps. The medium with oxidizing properties is injected into the module 3 through one or more pipes 3a connected to the module 3. The oxidizing bubbles in the fluid formed in the chamber 4 are led into the fluid outlet pipe 5 after passing through the second venturi tube 6. The second venturi tube 6 is preferably made of a material having oxidation resistance. The second venturi tube 6 is used to change the bubble diameter of the generated oxidation bubbles.

Materials having oxidation resistance used in various embodiments of the present invention include, but are not limited to, brass, bronze, nitrile rubber (nitrile), cast iron, Chemraz (all-poly), copper, CPVC (chlorinated polyvinyl chloride), cross-linked Polyethylene (PEX), Duracchlor-51, EPDM (ethylene propylene diene monomer), EPR (ethylene propylene rubber), ethylene-propylene, fiber reinforced plastic (FRD), Flexelene (flexible polyethylene), fluorosilicones, galvanized steel, glass, and the like,

(hastelloy), HDPE (high density polyethylene),

(chlorosulfonated polyethylene rubber),

Inconel (Inconel), Kalrez (Perfluoroether rubber), Inconel (Inconel-CrNiFe alloy), Kalrez (Perfluoroether rubber),

(polychlorotrifluoroethylene, PCTFE), LDPE (low density polyethylene), magnesium, Monel (Monel copper-nickel alloy), natural rubber, neoprene, nylon, PEEK (polyetheretherketone), polyacrylate, Polyamide (PA), polycarbonate, polyethylene, polypropylene (glass filled) (GFPP), polysulfide, compounded urethane rubber, PVC (polyvinyl chloride), PVDF (polyvinylidene fluoride,

) Santoprene (Santoprene), silicone, stainless steel (304/316), stainless steel (other grades), mild steel, PTFE (polytetrafluoroethylene), titanium, Tygon (polyethylene), Vamac (vinyl acrylate elastomer), Viton (Viton) and zinc.

Experiment 1

In this first experiment carried out using the system shown in FIG. 1, oxidizing bubbles were generated and discharged into an acrylic tank containing 33L of ultrapure water. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 2L/min. Compressed air was injected into the module 3 through the pipe 3a at a flow rate of 0.0667L/min for delivery into the ultra-pure water in the chamber 4. The temperature of the ultrapure water is about 25 ℃ at atmospheric pressure. When the compressed air and the ultrapure water were flowed for 30 minutes, the bubble diameter was measured by a Malvern NanoSightTM NS300 instrument and the saturation percentage of dissolved oxygen was measured by an OrionTM StarTM A216 instrument. The mean diameter of the oxidation bubbles was 85.5nm, the SD 5.6nm, the D10 81.4nm, the D50 85.6nm, the D90 88.8nm, and the concentration of the oxidation bubbles was 2.37X 106 per ml. The percent saturation of dissolved oxygen in this experiment increased from 40% to 82%. Fig. 3 shows the distribution of the bubble diameters.

Experiment 2

In this second experiment, which was performed using the system shown in FIG. 1, oxidizing bubbles were generated and discharged into an acrylic tank containing 33L of ultrapure water. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 2L/min. Compressed air was injected into the module 3 through the pipe 3a at a flow rate of 0.01L/min for delivery into the ultra-pure water in the chamber 4. The temperature of the ultrapure water is about 25 ℃ at atmospheric pressure. The bubble diameter was measured by a Malvern NanoSightTM NS300 instrument while flowing compressed air and ultrapure water for 30 minutes. The mean diameter of the oxidation bubbles was 187nm, the SD 43.7nm, the D10 112.6nm, the D50 208.8nm, the D90 219.7nm, and the concentration of the oxidation bubbles was 1.34X 107 per ml. Fig. 4 shows the distribution of the bubble diameters.

Experiment 3

In this third experiment, which was performed using the system shown in FIG. 2, oxidizing bubbles were generated and discharged into an acrylic tank containing 4.5L of ultrapure water. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 1L/min. Compressed air was injected into the module 3 through the pipe 3a at a flow rate of 0.01L/min for delivery into the ultra-pure water in the chamber 4. The temperature of the ultrapure water is about 25 ℃ at atmospheric pressure. The bubble diameter was measured by a Malvern NanoSightTM NS300 instrument while flowing compressed air and ultrapure water for 30 minutes. The mean diameter of the oxidation bubbles was 153.7nm, SD 5.5nm, D10 145.7nm, D50 152.9nm, D90 159.6nm, and the concentration of the oxidation bubbles was 4.11X 106 per ml. Fig. 5 shows the distribution of the bubble diameters.

Experiment 4

In this fourth experiment performed using the system shown in FIG. 1, oxidation bubbles were generated and discharged into an acrylic tank containing 4.5L of ultrapure water, in order to investigate the oxidation-reduction potential (ORP) of the oxidation bubbles generated in the fluid of the present invention. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 1L/min. Ozone was injected into the module 3 through the pipe 3a at a flow rate of 0.01L/min so as to be delivered to the ultrapure water in the chamber 4. The temperature of the ultrapure water is about 25 ℃ at atmospheric pressure. ORP values of the oxidized bubbles in the fluid were measured by a HI98196 meter of Hanna instruments, when ozone and ultrapure water were flowed for 15 minutes. The ORP value of the oxidizing bubbles in the fluid is about 1000 mV.

Experiment 5

In this fifth experiment, which was performed using the system shown in fig. 1, oxidation bubbles were generated and discharged into an acrylic tank containing 4.5L of water added with escherichia coli (e. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 1L/min. Ozone is injected into the module 3 through the pipe 3a at a flow rate of 0.01L/min for delivery to the water containing e.coli (e.coli) in the chamber 4. At atmospheric pressure, the temperature of the water is about 23 ℃. When ozone and water containing escherichia coli were allowed to flow for 5 minutes, the oxidation-reduction potential (ORP) of the oxidizing bubbles in the fluid was measured. The ORP value of the oxidation bubbles measured in the fluid by the HI98196 meter of Hanna instruments is about 600 mV. The number of E.coli was reduced by about 99.9% according to the number of E.coli on a 3MTM Petrifilm test strip (incubated at 35 ℃ for 24 hours) in water samples collected before and after allowing ozone and water containing E.coli to flow for 5 minutes.

Experiment 6

In this sixth experiment, which was carried out using the system shown in FIG. 1, oxidizing bubbles were generated and discharged into an acrylic tank containing 4.5L of water containing 0.45ppm of methylene blue, in order to investigate the water treatment performance of the oxidizing bubbles generated in the fluid according to the present invention. Ultrapure water was circulated from the acrylic tank into the chamber 4 through the fluid inlet pipe 1 and the fluid outlet pipe 5 at a flow rate of 1L/min. Ozone was injected into the module 3 through the pipe 3a at a flow rate of 0.01L/min for delivery to the water containing 0.45ppm of methylene blue in the chamber 4. At atmospheric pressure, the temperature of the water containing 0.45ppm of methylene blue is about 23 ℃. The decrease in the concentration of methylene blue was measured by a spectrophotometer (LAMBDATM 750UV/VIS/NIR spectrophotometer) at a wavelength of 660 nm. After allowing ozone and water containing 0.45ppm of methylene blue to flow for 15 minutes, the concentration of methylene blue in the acrylic acid tank was reduced to zero. Fig. 6 shows the absorption spectra of water samples collected at different times when ozone and water containing 0.45ppm methylene blue began to flow. The maximum absorption peak of methylene blue at 660nm drops to zero within 15 minutes.

The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations will be apparent to practitioners skilled in the art.

The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (8)

1. A system for generating oxidizing bubbles in a fluid, the system comprising:

a fluid inlet tube;

a component having pores or micro-gaps configured to deliver a medium having oxidizing properties into the fluid, wherein the pores or gaps have a pore size of less than 10 to 50 microns;

a chamber configured to create a swirling flow of fluid that creates a reduced pressure in the central core and subjects the oxidizing bubbles on the aperture or slit surfaces of the component to strong separating forces, and to increase the contact time between the agent with oxidizing properties and the fluid and create oxidizing bubbles in the fluid with a maximum diameter of less than 500nm, wherein the gap between the walls of the chamber and the component is less than or equal to 0.5mm for assisting the formation of a swirling flow of fluid within the chamber at atmospheric pressure;

a first venturi connected in between the fluid outlet tube and the chamber; and

a fluid outlet tube connected to the chamber and configured to expel oxidizing bubbles in the fluid;

wherein the assembly of pores or micro-slits is a membrane or container attached to the end of one or more tubes in which the medium with oxidizing properties is injected into the assembly.

2. The system of claim 1, wherein the system is further characterized as being capable of generating oxidizing bubbles in the fluid having a bubble diameter of less than 450 nm.

3. The system of claim 1, wherein said fluid outlet tube, said first venturi tube, said micro-perforated or micro-slotted component, said chamber and said fluid outlet tube are made of a material having anti-oxidant properties selected from the group consisting of brass, bronze, nitrile rubber (nitrile), cast iron, Chemraz (all-poly), copper, CPVC (chlorinated polyvinyl chloride), cross-linked Polyethylene (PEX), Durachlor-51, EPDM (ethylene propylene diene monomer), EPR (ethylene propylene rubber), ethylene propylene, fiber reinforced plastic (FRD), Flexelene (flexible polyethylene), fluorosilicone, galvanized steel, glass, micro-perforated or micro-slotted components, and combinations thereof,

(hastelloy), HDPE (high density polyethylene),

(chlorosulfonated polyethylene rubber),

Inconel (Inconel), Kalrez (Perfluoroether rubber), Inconel (Inconel-CrNiFe alloy), Kalrez (Perfluoroether rubber),

(polychlorotrifluoroethylene, PCTFE), LDPE (low density polyethylene), magnesium, Monel (Monel copper-nickel alloy), natural rubber, neoprene, nylon, PEEK (polyetheretherketone), polyacrylate, Polyamide (PA), polycarbonate, polyethylene, polypropylene (glass filled) (GFPP), polysulfide, compounded urethane rubber, PVC (polyvinyl chloride), PVDF (polyvinylidene fluoride,

) Santoprene (Santoprene), silicone, stainless steel (304/316), stainless steel (other grades), mild steel, PTFE (polytetrafluoroethylene), titanium, Tygon (polyethylene), Vamac (vinyl acrylate elastomer), Viton (Viton) and zinc.

4. The system of claim 1, wherein the medium having oxidizing properties includes, but is not limited to, at least one oxidizing compound selected from the group consisting of air, oxygen, and ozone.

5. The system of claim 1, wherein the fluid is selected from the group consisting of water, distilled water, deionized water, ultrapure water, aqueous solutions, seawater, wastewater, and oils.

6. The system of claim 1, wherein there is a gap of 0.1 to 0.5mm between the chamber and the assembly.

7. The system of claim 1, wherein the system further comprises a second venturi connected between the chamber and the fluid outlet pipe; wherein the second venturi is configured to change a bubble diameter of oxidizing bubbles in the fluid.

8. The system of claim 8, wherein the second venturi tube is made of a material having oxidation resistance selected from the group consisting of brass, bronze, nitrile rubber (nitrile), cast iron, Chemraz (all poly), copper, CPVC (chlorinated polyvinyl chloride), cross-linked Polyethylene (PEX), Durachlor-51, EPDM (ethylene propylene diene monomer), EPR (ethylene propylene rubber), ethylene propylene, fiber reinforced plastic (FRD), Flexelene (flexible polyethylene), fluorosilicone, galvanized steel, glass, and,

(hastelloy), HDPE (high density polyethylene),

(chlorosulfonated polyethylene rubber),

Inconel (Inconel), Kalrez (Perfluoroether rubber), Inconel (Inconel-CrNiFe alloy), Kalrez (Perfluoroether rubber),

(polychlorotrifluoroethylene, PCTFE), LDPE (low density polyethylene), magnesium, Monel (Monel copper-nickel alloy), natural rubber, neoprene, nylon, PEEK (polyetheretherketone), polyacrylate, Polyamide (PA), polycarbonate, polyethylene, polypropylene (glass filled) (GFPP), polysulfide, compounded urethane rubber, PVC (polyvinyl chloride), PVDF (polyvinylidene fluoride,

) Santoprene (Santoprene), silicone, stainless steel (304/316), stainless steel (other grades), mild steel, PTFE (polytetrafluoroethylene), titanium, Tygon (polyethylene), Vamac (vinyl acrylate elastomer), Viton (Viton) and zinc.

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