阅读说明：本技术 废气处理用耐高温陶瓷纤维滤管 (High-temperature resistant ceramic fiber filter tube for waste gas treatment ) 是由 孙正庭 王魁 于 2021-08-11 设计创作，主要内容包括：本发明公开了废气处理用耐高温陶瓷纤维滤管,属于耐火纤维技术领域。且该耐高温陶瓷纤维滤管,通过以下步骤制成：步骤一、溶液c的制备；步骤二、浆料的制备；步骤三、陶瓷纤维滤管的抽滤和烧结。且本发明利用改性剂对硅溶胶进行了改性,增加了硅溶胶与有机粘结剂的相容性,提高烧结的陶瓷纤维滤管原料之间的粘结性；且所述的改性剂为改性聚倍半硅氧烷,使硅溶胶中二氧化硅颗粒表面修饰的为聚倍半硅氧烷结构,利用了聚倍半硅氧烷作为陶瓷前驱体所具有的结构特征,其与硅溶胶类似地起到高温烧结剂的作用,紧紧地粘合着莫来石纤维,提高了陶瓷纤维滤管的耐高温性能和机械性能。(The invention discloses a high-temperature resistant ceramic fiber filter tube for waste gas treatment, and belongs to the technical field of refractory fibers. The high-temperature resistant ceramic fiber filter tube is prepared by the following steps: step one, preparing a solution c; step two, preparing slurry; and step three, carrying out suction filtration and sintering on the ceramic fiber filter tube. In addition, the invention utilizes the modifier to modify the silica sol, increases the compatibility of the silica sol and the organic binder, and improves the caking property between the raw materials of the sintered ceramic fiber filter tube; the modifier is modified polysilsesquioxane, so that the surface of the silicon dioxide particles in the silica sol is modified to be a polysilsesquioxane structure, the structural characteristics of the polysilsesquioxane serving as a ceramic precursor are utilized, the polysilsesquioxane plays a role of a high-temperature sintering agent similar to the silica sol, mullite fiber is tightly bonded, and the high-temperature resistance and the mechanical property of the ceramic fiber filter tube are improved.)

1. High temperature resistant ceramic fiber filter tube for exhaust-gas treatment, its characterized in that: is prepared by the following steps:

step one, mixing water and an emulsifier, adding silica sol, adjusting the pH of the solution to 5-7, adding modified polysilsesquioxane, and stirring at room temperature for 12 hours to obtain a solution a; uniformly mixing water, a dispersing agent, an organic binder and boric acid to obtain a mixed solution b; uniformly mixing the solution a and the solution b to obtain a solution c;

step two, adding ceramic fibers into the solution c, and stirring for 70-100min to obtain slurry;

and step three, carrying out vacuum filtration on the slurry, carrying out wet demolding after preforming, then drying and curing, degreasing, and sintering to obtain the high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

2. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: the modified polysilsesquioxane is prepared by the following steps:

and mixing epoxy POSS, aminopropyl triethoxysilane, triethylamine and glacial acetic acid, heating to 72 ℃, reacting for 7 hours, and performing rotary evaporation to obtain the modified polysilsesquioxane.

3. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: in the first step, the mass ratio of water, emulsifier, silica sol and modified polysilsesquioxane is 50-100: 0.5-1.2: 15-20: 2.5-5.

4. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: in the preparation process of the solution b in the step one, the mass ratio of water, the dispersing agent, the organic binder and the boric acid is 80-100: 0.5-1.5: 2-4.5: 10-15.

5. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: the mass ratio of the solution a to the solution b in the first step is 20-35: 100.

6. the high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: in the second step, the adding mass of the ceramic fiber is 5-12% of the mass of the solution c.

7. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: in the third step, the suction filtration pressure is 0.06-0.08MPa, and the suction filtration time is 30-45 min; drying at 70-120 deg.C for 12-24 hr; the sintering temperature is 1100-1200 ℃ and the sintering time is 3-5 h.

8. The high temperature resistant ceramic fiber filter tube for exhaust gas treatment according to claim 1, wherein: the mass fraction of the silicon dioxide in the silica sol is 30-45%, and the particle size of the silicon dioxide is 60-90 nm.

Technical Field

The invention belongs to the technical field of refractory fibers, and particularly relates to a high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

Background

The industrial waste gas is not only high in temperature, but also contains a large amount of dust and harmful gases. At present, high-temperature dust removal technologies such as bag-type dust removal, wet dust removal, electrostatic dust removal, cyclone dust removal and the like have been successful in the market, but the dust removal technologies have some problems in the application process of waste gas purification. Firstly, the bag type dust collector is limited by the temperature resistance of a cloth bag and cannot be used at the temperature of more than 250 ℃, and a circulating water chilling or air cooling mode is usually adopted to reduce the temperature of high-temperature flue gas to below 250 ℃ and then remove dust, so that the problem of water resource waste and secondary pollution of water resources is caused; the wet dust removal also consumes a large amount of water resources, so that the problems of water resource waste and secondary pollution of the water resources are caused; the electrostatic precipitator occupies a large area, has high investment cost, and has the problems of sensitivity to the properties of specific resistance, gas components and the like of dust, corrosion of an electric level and the like.

The ceramic fiber is a fibrous light refractory material, and its diameter is 2-5 micrometers, length is 30-250mm at most, and its surface is made into the form of smooth cylinder. Because of the advantages of light weight, high temperature resistance, good thermal stability, low thermal conductivity, small specific heat, mechanical vibration resistance and the like, the material is widely applied to the industries of machinery, metallurgy, chemical industry, petroleum, ceramics, glass, electronics and the like. Compared with the traditional granular filter material, the filter material prepared from the ceramic fiber has the advantages of large specific surface area, larger interface adsorption capacity, capability of intercepting suspended matters and better filter effect; compared with the traditional cloth bag and other filter materials, the cloth bag filter material has the characteristic of being used in a high-temperature environment or even an ultrahigh-temperature environment (less than or equal to 1400 ℃); compared with porous ceramic and metal filter materials, the material has the characteristics of low resistance, energy consumption saving, and good chemical stability and thermal shock resistance. The short-fiber ceramic fiber filter material has the advantages of low manufacturing cost, high porosity, small filtering resistance and the like, but also has the technical problems of low mechanical strength, easy brittle fracture after long-term use at high temperature and the like, and is not suitable for gas filtration in a high-pressure environment.

Therefore, the invention provides a high-temperature resistant ceramic fiber filter tube for waste gas treatment.

Disclosure of Invention

The invention aims to provide a high-temperature resistant ceramic fiber filter tube for waste gas treatment, which is used for solving the technical problems that the existing ceramic fiber filter tube has low mechanical strength and is easy to brittle fracture after being used at high temperature for a long time.

The purpose of the invention can be realized by the following technical scheme:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, mixing water and an emulsifier according to a ratio, then adding silica sol, adjusting the pH of the solution to 5-7 with hydrochloric acid under stirring, adding a modifier, and stirring at room temperature for 12 hours to obtain a solution a; uniformly mixing water, a dispersing agent, an organic binder and boric acid according to a ratio to obtain a mixed solution b; finally, uniformly mixing the solution a and the solution b according to the proportion to obtain a solution c;

step two, adding ceramic fiber into the solution c, and stirring at the speed of 400-;

and step three, injecting the slurry into a suction filtration mould for vacuum suction filtration, performing wet demolding, drying, curing, degreasing, and sintering at high temperature to obtain the high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

Further, in the preparation process of the solution a in the step one, the mass ratio of water, the emulsifier, the silica sol and the modifier is 50-100: 0.5-1.2: 15-20: 2.5-5.

Further, in the preparation process of the solution b in the step one, the mass ratio of water, the dispersing agent, the organic binder and the boric acid is 80-100: 0.5-1.5: 2-4.5: 10-15.

Further, the mass ratio of the solution a to the solution b in the step one is 20-35: 100.

further, the adding mass of the ceramic fiber in the second step is 5-12% of the mass of the solution c.

Further, the ceramic fiber is mullite fiber.

Further, in the third step, the suction filtration pressure is 0.06-0.08MPa, and the suction filtration time is 30-45 min.

Further, in the third step, when drying and curing, the drying temperature is 70-120 ℃, and the drying time is 12-24 h.

Further, in the third step, when the high-temperature sintering is carried out, the sintering temperature is 1100-1200 ℃, and the sintering time is 3-5 h.

Further, the mass fraction of the silicon dioxide in the silica sol is 30-45%, and the particle size of the silicon dioxide is 60-90 nm.

Further, the emulsifier is one of sodium dodecyl sulfate and sodium dodecyl sulfate.

Further, the dispersant is one of hydroxyethyl methyl cellulose and methyl cellulose.

Further, the organic binder is any one of hydroxyethyl methyl cellulose, methyl cellulose and polyvinylpyrrolidone.

Further, the modifier is modified polysilsesquioxane, and the molecular structural formula of the modifier is as follows:

in the first step, the Si-O bond in the modifier and the O-H bond on the surface of the silica particle undergo a condensation reaction under an acidic condition to form a Si-O-Si bond, so that the surface of the silica particle in the silica sol is modified with a polysilsesquioxane structure, and the modified silica sol added into a slurry system can cause the following changes or effects: on one hand, the polysilsesquioxane reduces the water solubility of the silica sol, increases the compatibility of the silica sol and an organic binder, improves the cohesiveness among the raw materials of the sintered ceramic fiber filter tube, and improves the mechanical strength of the ceramic fiber filter tube; on the other hand, in the slurry, the modified silica sol is coated on the surface of mullite fiber, the polysilsesquioxane has a closed cage-shaped structure consisting of inorganic Si-O-Si chain links, and after sintering, the residue is mainly a silicon compound (SiO)₂SiC, SiCO), all have high heat resistance and can be converted to SiO at high temperatures₂And the ceramic structures such as SiC and the like play the role of a high-temperature sintering agent similar to the silica sol, and the mullite fiber is tightly bonded, so that the compressive strength and the high-temperature resistance of the ceramic fiber filter tube are improved.

Further, the modifier is prepared by the following steps:

s1, mixing absolute ethyl alcohol and absolute methyl alcohol, heating to 40 ℃, adding water, adjusting the pH of the solution to 5-6 by hydrochloric acid, stirring for 30min, dropwise adding phenyltriethoxysilane and beta-3, 4-epoxy cyclohexyl ethyl trimethoxysilane, and controlling the total molar ratio of water to silane to be 2: 1, phenyltriethoxysilane and beta-3, 4-epoxycyclohexylethyltrimethoxysilane are mixed in a molar ratio of 7-8: 1, carrying out hydrolysis reaction for 48h, adjusting the pH of a reaction solution to be neutral by using an aqueous solution of sodium hydroxide, carrying out reduced pressure rotary evaporation to remove a solvent, washing for multiple times, drying by using anhydrous sodium sulfate, and filtering to obtain epoxy group POSS;

s2, mixing epoxy POSS, aminopropyl triethoxysilane, triethylamine and glacial acetic acid, heating to 72 ℃, reacting for 7 hours, and removing the glacial acetic acid by rotary evaporation to obtain the modified polysilsesquioxane, wherein the molar ratio of the epoxy POSS to the aminopropyl triethoxysilane to the triethylamine is 1: 1.1-1.3: 1.3-1.5, the reaction of amino and epoxy is utilized in the reaction process, so that the epoxy POSS is graft-modified by aminopropyl triethoxy silane silicon oxygen coupling agent.

The invention has the beneficial effects that:

according to the invention, the silicon sol is modified by using the modifier, so that the water solubility of the silicon sol is reduced, the compatibility of the silicon sol and an organic binder is increased, the adhesion among the raw materials of the ceramic fiber filter tube is improved, and the mechanical strength of the ceramic fiber filter tube is improved;

the modifying agent is modified polysilsesquioxane, the modifying agent enables the surface of the silicon dioxide particles in the silica sol to be modified into a polysilsesquioxane structure, after sintering, the structural characteristics of the polysilsesquioxane as a ceramic precursor are utilized, and the residues after sintering are mainly silicon compounds (SiO)₂SiC, SiCO) having excellent high temperature resistance and being convertible to SiO at high temperature₂And the SiC and other ceramic structures play the role of a high-temperature sintering agent similar to the silica sol, and tightly bond mullite fibers, so that the compressive strength and the high-temperature resistance of the ceramic fiber filter tube are improved, and the problems of brittle fracture and the like of the ceramic fiber filter tube under the long-term high-temperature condition are solved.

In conclusion, the ceramic fiber filter tube provided by the invention has good mechanical property and high temperature resistance.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

modifying agent: a modified polysilsesquioxane made by the steps of:

s1, mixing 30mL of anhydrous ethanol and 30mL of anhydrous methanol, heating to 40 ℃, adding 0.16mol of water, adjusting the pH value of the solution to 5.6 by hydrochloric acid, stirring for 30min, dropwise adding 0.07mol of phenyltriethoxysilane and 0.01mol of beta-3, 4-epoxy cyclohexyl ethyl trimethoxysilane at the speed of 1 drop/second, carrying out hydrolysis reaction for 48h, adjusting the pH value of the reaction solution to be neutral by using an aqueous solution of sodium hydroxide, carrying out reduced pressure rotary evaporation to remove the solvent, washing for 2 times, drying with anhydrous sodium sulfate, and filtering to obtain epoxy group POSS;

s2, mixing 0.1mol of epoxy POSS, 0.11mol of aminopropyltriethoxysilane, 0.13mol of triethylamine and glacial acetic acid, heating to 72 ℃, reacting for 7 hours, and performing rotary evaporation to remove the glacial acetic acid to obtain the modified polysilsesquioxane.

Example 2:

modifying agent: a modified polysilsesquioxane made by the steps of:

s1, mixing 30mL of anhydrous ethanol and 30mL of anhydrous methanol, heating to 40 ℃, adding 0.16mol of water, adjusting the pH of the solution to 6 by hydrochloric acid, stirring for 30min, dropwise adding 0.07mol of phenyltriethoxysilane and 0.01mol of beta-3, 4-epoxycyclohexylethyltrimethoxysilane at the speed of 1 drop/second, carrying out hydrolysis reaction for 48h, adjusting the pH of the reaction solution to be neutral by using an aqueous solution of sodium hydroxide, carrying out reduced pressure rotary evaporation to remove the solvent, washing for 2 times, drying with anhydrous sodium sulfate, and filtering to obtain epoxy group POSS;

s2, mixing 0.1mol of epoxy POSS, 0.13mol of aminopropyltriethoxysilane, 0.15mol of triethylamine and glacial acetic acid, heating to 72 ℃, reacting for 7 hours, and performing rotary evaporation to remove the glacial acetic acid to obtain the modified polysilsesquioxane.

Example 3:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, uniformly mixing water and an emulsifier, then adding silica sol, adjusting the pH of the solution to 5 by using 0.1M hydrochloric acid under stirring, adding the modifier prepared in example 1, and stirring at room temperature for 12 hours to obtain a solution a, wherein the mass ratio of the water to the emulsifier to the silica sol to the modifier is 50: 0.5: 15: 2.5; and then mixing water, a dispersing agent, an organic binder and boric acid according to a mass ratio of 80: 0.5: 2: 10, uniformly mixing to obtain a mixed solution b; and finally, mixing the solution a and the solution b according to a mass ratio of 20: 100, uniformly mixing to obtain a solution c;

step two, adding ceramic fibers into the solution c, stirring at the speed of 400r/min for 70min to obtain slurry, and controlling the adding mass of the ceramic fibers to be 5% of the mass of the solution c;

and step three, injecting the slurry into a suction filtration mould, carrying out suction filtration for 30min under the pressure of 0.06MPa, carrying out wet demoulding after preforming, drying and curing for 12h at 70 ℃, degreasing, and sintering for 5h at 1100 ℃ to obtain the high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

Wherein the mass fraction of the silicon dioxide in the silica sol is 30%, and the particle size of the silicon dioxide is 60 nm; the emulsifier is sodium dodecyl sulfate; the dispersant is hydroxyethyl methyl cellulose; the organic binder is hydroxyethyl methyl cellulose.

Example 4:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, uniformly mixing water and an emulsifier, then adding silica sol, adjusting the pH of the solution to 5.4 by using 0.1M hydrochloric acid under stirring, adding the modifier prepared in the embodiment 2, and stirring at room temperature for 12 hours to obtain a solution a, wherein the mass ratio of the water to the emulsifier to the silica sol to the modifier is 60: 0.8: 17: 3.5; and then mixing water, a dispersing agent, an organic binder and boric acid according to a mass ratio of 90: 1: 3: 12, uniformly mixing to obtain a mixed solution b; and finally, mixing the solution a and the solution b according to a mass ratio of 25: 100, uniformly mixing to obtain a solution c;

step two, adding ceramic fibers into the solution c, stirring for 80min at the speed of 500r/min to obtain slurry, and controlling the adding mass of the ceramic fibers to be 8% of the mass of the solution c;

and step three, injecting the slurry into a suction filtration mould, carrying out suction filtration for 35min under the pressure of 0.08MPa, carrying out wet demoulding after preforming, drying and curing for 18h at the temperature of 90 ℃, degreasing, and sintering for 4h at the temperature of 1100 ℃ to obtain the high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

Wherein the mass fraction of the silicon dioxide in the silica sol is 35%, and the particle size of the silicon dioxide is 70 nm; the emulsifier is sodium dodecyl sulfate; the dispersant is methyl cellulose; the organic binder is methyl cellulose.

Example 5:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, uniformly mixing water and an emulsifier, then adding silica sol, adjusting the pH of the solution to 7 by hydrochloric acid under stirring, adding the modifier prepared in the embodiment 1, and stirring at room temperature for 12 hours to obtain a solution a, wherein the mass ratio of the water to the emulsifier to the silica sol to the modifier is 100: 1.2: 20: 5; then mixing water, a dispersing agent, an organic binder and boric acid according to the mass ratio of 100: 1.5: 4.5: 15, uniformly mixing to obtain a mixed solution b; and finally, mixing the solution a and the solution b according to a mass ratio of 35: 100 to obtain a solution c, a solution a and a solution b;

step two, adding ceramic fibers into the solution c, stirring for 100min at the speed of 600r/min to obtain slurry, and controlling the adding mass of the ceramic fibers to be 12% of the mass of the solution c;

and step three, injecting the slurry into a suction filtration mould, carrying out suction filtration for 45min under the pressure of 0.08MPa, carrying out wet demoulding after preforming, drying and curing for 24h at 120 ℃, degreasing, and sintering for 3h at 1200 ℃ to obtain the high-temperature-resistant ceramic fiber filter tube for waste gas treatment.

Wherein the mass fraction of the silicon dioxide in the silica sol is 45%, and the particle size of the silicon dioxide is 90 nm; the emulsifier is sodium dodecyl sulfate; the dispersant is hydroxyethyl methyl cellulose; the organic binder is polyvinylpyrrolidone.

Comparative example 1:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, uniformly mixing water and an emulsifier, then adding silica sol, adjusting the pH of the solution to 5 by using 0.1M hydrochloric acid under stirring, adding beta-3, 4-epoxy cyclohexyl ethyl trimethoxy silane, and stirring at room temperature for 12 hours to obtain a solution a, wherein the mass ratio of the water to the emulsifier to the silica sol to the modifier is 50: 0.5: 15: 2.5; and then mixing water, a dispersing agent, an organic binder and boric acid according to a mass ratio of 80: 0.5: 2: 10, uniformly mixing to obtain a mixed solution b; and finally, mixing the solution a and the solution b according to a mass ratio of 20: 100 to obtain a solution c;

step two, adding ceramic fibers into the solution c, stirring at the speed of 400r/min for 70min to obtain slurry, and controlling the adding mass of the ceramic fibers to be 5% of the mass of the solution c;

and step three, injecting the slurry into a suction filtration mould, carrying out suction filtration for 30min under the pressure of 0.06MPa, carrying out wet demoulding after preforming, then drying and curing for 12h at 70 ℃, degreasing, and then sintering for 5h at 1100 ℃ to obtain the high-temperature resistant ceramic fiber filter tube for waste gas treatment.

Wherein the mass fraction of the silicon dioxide in the silica sol is 30%, and the particle size of the silicon dioxide is 60 nm; the emulsifier is sodium dodecyl sulfate; the dispersant is hydroxyethyl methyl cellulose; the organic binder is hydroxyethyl methyl cellulose.

Comparative example 2:

the high-temperature resistant ceramic fiber filter tube for waste gas treatment is prepared by the following steps:

step one, uniformly mixing water and an emulsifier, and then adding silica sol to obtain a solution a, wherein the mass ratio of the water to the emulsifier to the silica sol is 60: 0.8: 17; and then mixing water, a dispersing agent, an organic binder and boric acid according to a mass ratio of 90: 1: 3: 12, uniformly mixing to obtain a mixed solution b; and finally, mixing the solution a and the solution b according to a mass ratio of 25: 100 to obtain a solution c;

step two, adding ceramic fibers into the solution c, stirring for 80min at the speed of 500r/min to obtain slurry, and controlling the adding mass of the ceramic fibers to be 8% of the mass of the solution c;

and step three, injecting the slurry into a suction filtration mould, carrying out suction filtration for 35min under the pressure of 0.08MPa, carrying out wet demoulding after preforming, drying and curing for 18h at the temperature of 90 ℃, degreasing, and sintering for 4h at the temperature of 1100 ℃ to obtain the high-temperature resistant ceramic fiber filter tube for waste gas treatment.

Wherein the mass fraction of the silicon dioxide in the silica sol is 35%, and the particle size of the silicon dioxide is 70 nm; the emulsifier is sodium dodecyl sulfate; the dispersant is methyl cellulose; the organic binder is methyl cellulose.

Comparative example 3:

a ceramic fiber filter tube described in example 1 of chinese patent publication No. CN 109665764A.

Example 6:

the wall thicknesses of the ceramic fiber filter tubes obtained in examples 3 to 5 and comparative examples 1 to 3 were measured, and the ceramic fiber filter tubes obtained in examples 3 to 5 and comparative examples 1 to 3 were subjected to the following performance tests:

pore diameter performance: the pore diameter is tested by adopting a bubble experiment method, the porosity is tested by adopting a water absorption method, and the testing instrument adopts a BSD-PB pore diameter analyzer of Beschild Instrument science and technology (Beijing) Limited company, wherein the pore diameter is a peak value, and the porosity is a peak value;

mechanical strength properties: testing the radial compressive strength by using an electronic universal tester (WDW-50S, New optical instruments Co., Ltd. of the south of Ji times);

the filtration performance is as follows: the filtration resistance is the pressure drop (Pa) at the wind speed of 1m/min under the standard working condition;

the measured data are shown in the following table.

As can be seen from the data, the ceramic fiber filter tube provided by the invention has excellent compressive strength, and meanwhile, the porosity is more than 92%, the pore radius is 189 mu m, and the air permeability resistance is 146-143 Pa.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is illustrative and explanatory only and is not intended to be exhaustive or to limit the invention to the precise embodiments described, and various modifications, additions, and substitutions may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the claims.