阅读说明：本技术 一种高效抗烧泡沫液及其制备方法 (Efficient anti-burning foam liquid and preparation method thereof ) 是由 张平 徐晓兰 吴琼 童晶 陈永红 于 2021-01-20 设计创作，主要内容包括：本发明公开了一种高效抗烧泡沫液及其制备方法,属于消防领域,以解决现有的泡沫液抗溶和抗烧能力差导致灭火速度慢,复燃可能性大的问题,按重量份计,所述泡沫液包括：去离子水270份,改性纤维素1份,碳酸氢盐16份,表面活性剂10份,尿素25份,发泡剂30份,乳化剂10份,发泡剂及表面活性剂复配使消防灭火剂喷洒灭火时可产生大量抗烧泡沫,并堆积在燃烧物体的表面上成层状覆盖,隔绝助燃气体,形成窒息灭火,使灭火速度快,效果好,可以抵抗水溶性可燃、易燃液体的破坏,改性纤维有韧性,耐烧,保护成层状存留时间长,可使火场灭火后不复燃。(The invention discloses a high-efficiency anti-burning foam liquid and a preparation method thereof, belongs to the field of fire fighting, and aims to solve the problems of slow fire extinguishing speed and high re-burning possibility caused by poor anti-dissolution and anti-burning capabilities of the existing foam liquid, wherein the foam liquid comprises the following components in parts by weight: 270 parts of deionized water, 1 part of modified cellulose, 16 parts of bicarbonate, 10 parts of surfactant, 25 parts of urea, 30 parts of foaming agent, 10 parts of emulsifier, foaming agent and surfactant are compounded to ensure that the fire extinguishing agent can generate a large amount of anti-burning foam when sprayed to extinguish fire, and the anti-burning foam is accumulated on the surface of a burning object to be covered in a layered manner to isolate combustion-supporting gas to form stifling fire extinguishing, so that the fire extinguishing speed is high, the effect is good, the damage of water-soluble combustible and flammable liquid can be resisted, the modified fiber is tough and burning-resistant, the layered retention time is long, and the fire can not be reignited after the fire scene extinguishment.)

1. A high-efficiency anti-burning foam liquid is characterized in that: the foam liquid comprises the following components in parts by weight: 260-280 parts of deionized water, 0.8-1.2 parts of modified cellulose, 15-18 parts of bicarbonate, 8-12 parts of surfactant, 22-28 parts of urea, 24-36 parts of foaming agent and 8-12 parts of emulsifier.

2. The high-efficiency anti-burning foam concentrate as claimed in claim 1, wherein the foam concentrate comprises, in parts by weight: 270 parts of deionized water, 1 part of modified cellulose, 16 parts of coating bicarbonate, 10 parts of surfactant, 25 parts of urea, 30 parts of foaming agent and 10 parts of emulsifier.

3. The foam concentrate of claim 1 or 2, wherein the foam concentrate further comprises xanthan gum 0.5-1 parts by weight.

4. The foam concentrate of claim 1 or 2, wherein the foam concentrate further comprises 5-10 parts by weight of polyethylene glycol.

5. The foam concentrate of claim 1 or 2, wherein the foam concentrate further comprises 1-5 parts by weight of an anti-freezing agent.

6. The foam concentrate of claim 1 or 2, wherein the surfactant is an anionic surfactant or an amphoteric surfactant.

7. The foam concentrate of claim 1 or 2, wherein the foaming agent is one or more of alkyl glycoside, coconut oil fatty acid glycol amide, imidazoline, and sodium lauryl sulfate.

8. The foam concentrate of claim 1 or 2, wherein the bicarbonate is a coated bicarbonate.

9. A method for preparing the high-efficiency anti-burning foam concentrate as claimed in any one of claims 1 to 8, which comprises the following steps:

taking deionized water according to the weight parts, heating to 36-44 ℃, adding the antifreezing agent and xanthan gum, fully stirring for 10-30min, then adding polyethylene glycol, modified cellulose and urea, fully stirring for 10-30min, adding the surfactant, fully stirring for 10-30min, adding the foaming agent, the emulsifier, the bicarbonate and the preservative, continuously stirring for 10-30min, and cooling to obtain the finished product.

10. The method according to claim 9, wherein the bicarbonate is prepared by a method comprising the steps of,

step 1, putting polyether glycol into a three-mouth bottle with a stirrer, a thermometer and a vacuum connecting pipe, stirring and heating, and carrying out vacuum dehydration for 2 hours at the temperature of l 10-115 ℃;

step 2, cooling polyether diol to 40-50 ℃, adding toluene diisocyanate, wherein the mass ratio of the polyether diol to the toluene diisocyanate is 1.1-1.2:1, heating to 80 ℃, starting to react, and cooling to room temperature for later use when the mass fraction of NCO is 5-7% according to the analysis and detection of a di-n-butylamine method;

and 3, spraying the reaction product obtained in the step 2 and diethyltoluenediamine according to the mass ratio of 3-5:1 onto the bicarbonate powder by using a spraying system respectively, wherein the spraying pressure of a nozzle during spraying is 0.7-1.2MPa, the temperature is 30-40 ℃, the spraying amount accounts for 5% -7% of the total sodium bicarbonate, stirring the sodium bicarbonate powder continuously during spraying, and cooling to obtain the coated bicarbonate.

Technical Field

The invention discloses a high-efficiency anti-burning foam liquid and a preparation method thereof, belongs to the field of fire fighting, and particularly relates to the technical field of foam liquid.

Background

The fire extinguisher is a portable fire extinguishing tool. Chemical substances are placed in the fire extinguisher for saving and extinguishing fire. The fire extinguisher is one of common fire-proof facilities, is stored in public places or places where fire disasters may happen, and different fire extinguishers of different types are filled with different components and are specially designed for different fires.

Fire extinguishers are classified into dry powder extinguishers, foam extinguishers, carbon dioxide extinguishers, 1211 extinguishers, and the like. The nozzle of the dry powder fire extinguisher is very small and is easily blocked by deposited dust and hardened dry powder, so that a user finds that the nozzle is blocked after finding the fire extinguisher in a hurry, the best fire extinguishing time is lost, and unnecessary property loss is caused; the carbon dioxide fire extinguisher has poor re-ignition resistance, and carbon dioxide is a medium-toxicity substance; 1211 eliminates the fire extinguisher containing environmental pollutants. The foam liquid is an effective fire extinguishing agent for extinguishing inflammable and volatile liquid after burning, and mainly forms a condensed floating layer of foam rice on the surface of the liquid to play a role in suffocation and cooling. The existing foaming agent is very simple and has poor anti-burning capacity, so that the fire extinguishing speed is slow, the effect is poor, the re-burning possibility is enhanced, and particularly, the fire extinguishing effect is poor for the fire of polar combustible liquid.

Disclosure of Invention

The invention aims to: provides a high-efficiency anti-burning foam liquid and a preparation method thereof, and aims to solve the problems of low fire extinguishing speed, poor effect and high re-burning possibility caused by simple foam liquid and poor anti-dissolving and anti-burning capabilities in the prior art.

The technical scheme adopted by the invention is as follows:

a high-efficiency anti-burning foam liquid comprises the following components in parts by weight: 280 parts of water 260-280 parts, 0.8-1.2 parts of modified cellulose, 15-18 parts of bicarbonate, 8-12 parts of surfactant, 22-28 parts of urea, 24-36 parts of foaming agent and 8-12 parts of emulsifier.

In the technical scheme of the application, the bicarbonate is an inorganic foaming agent and releases carbon dioxide during decomposition; urea is used as a stabilizer to stabilize the formed foam liquid, and can be partially decomposed into ammonia gas after encountering fire to promote fire extinguishment, the emulsifier reduces the interfacial tension of each component in the mixed system, and a firmer film is formed on the surface of a micro-droplet to prevent the components from aggregating with each other, so that the mixed system is kept uniform, and when the fire extinguishing agent is sprayed for fire extinguishment by compounding the foaming agent and the surfactant, a large amount of anti-burning foam can be generated and accumulated on the surface of a combustion object to form layered coverage, so that combustion-supporting gas is isolated to form asphyxiation and fire extinguishment, so that the fire extinguishment speed is high, the effect is good, the damage of water-soluble combustible and combustible liquid can be resisted, the modified fiber is tough and durable, the protection layered retention time is long, and the fire extinguishment can be prevented after fire scene is extinguished. Solves the problems of low fire extinguishing speed, poor effect and high re-burning possibility caused by simple foam liquid, poor dissolution resistance and poor burning resistance in the prior art.

Preferably, the foam concentrate comprises the following components in parts by weight: 270 parts of deionized water, 1 part of modified cellulose, 16 parts of bicarbonate, 10 parts of surfactant, 25 parts of urea, 30 parts of foaming agent and 10 parts of emulsifier.

Preferably, the foam concentrate also comprises 0.5 to 1 part of xanthan gum by weight.

More preferably, the foam concentrate also comprises 0.8 part of xanthan gum by weight.

Preferably, the foam concentrate further comprises 10 parts by weight of polyethylene glycol.

More preferably, the foam liquid further comprises 8 parts by weight of polyethylene glycol, and the molecular weight of the polyethylene glycol is 2000-2500 daltons.

Preferably, the foam liquid also comprises 1-5 parts of an antifreezing agent in parts by weight.

More preferably, the foam liquid further comprises 3 parts by weight of an antifreezing agent, and the antifreezing agent comprises ethylene glycol or propylene glycol.

Preferably, the foam concentrate also comprises 0.03-0.05 part of preservative by weight.

More preferably, the foam liquid also comprises 0.04 part of preservative by weight, and the preservative comprises sodium diacetate or natamycin.

Preferably, the emulsifier is OP-10.

Preferably, the surfactant is an anionic surfactant or an amphoteric surfactant.

Preferably, the foaming agent is one or more of alkyl glycoside, coconut fatty acid glycol amide, imidazoline and sodium dodecyl sulfate.

Preferably, the bicarbonate is coated bicarbonate, and the bicarbonate is powder.

A preparation method of high-efficiency anti-burning foam liquid comprises the following steps:

taking deionized water according to the weight parts, heating to 36-44 ℃, adding the antifreezing agent and xanthan gum, fully stirring for 10-30min, then adding polyethylene glycol, modified cellulose and urea, fully stirring for 10-30min, adding the surfactant, fully stirring for 10-30min, adding the foaming agent, the emulsifier, the bicarbonate and the preservative, continuously stirring for 10-30min, and cooling to obtain the finished product.

Preferably, the preparation method of the coated bicarbonate comprises the following steps:

step 1, putting polyether glycol into a three-mouth bottle with a stirrer, a thermometer and a vacuum connecting pipe, stirring and heating, and carrying out vacuum dehydration for 2 hours at the temperature of l 10-115 ℃;

step 2, cooling polyether diol to 40-50 ℃, adding toluene diisocyanate, wherein the mass ratio of the polyether diol to the toluene diisocyanate is 1.1-1.2:1, heating to 80 ℃, starting to react, and cooling to room temperature for later use when the mass fraction of NCO is 5-7% according to the analysis and detection of a di-n-butylamine method;

and 3, spraying the reaction product obtained in the step 2 and diethyltoluenediamine according to the mass ratio of 3-5:1 onto the bicarbonate powder by using a spraying system respectively, wherein the spraying pressure of a nozzle during spraying is 0.7-1.2MPa, the temperature is 30-40 ℃, the spraying amount accounts for 5% -7% of the total sodium bicarbonate, stirring the sodium bicarbonate powder continuously during spraying, and cooling to obtain the coated bicarbonate.

More preferably, in the preparation method, the stirring speed is 500-3000 rpm.

The xanthan gum is added into the foam liquid, can be quickly dissolved in water, has a good suspension effect on bicarbonate and an emulsifier, and further enables all components to be fully and uniformly mixed;

polyethylene glycol is added into the foam liquid, so that the foam liquid is well compatible with an emulsifier, has good dispersibility, further enables all components to be uniformly mixed, has good lubricity, and enables the foam liquid to easily flow out when in use.

NCO is an isocyanate group.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. according to the invention, the foaming agent and the surfactant are compounded, so that a great amount of anti-burning foam can be generated and accumulated on the surface of a burning object to be covered in a layered manner when the fire extinguishing agent is sprayed for fire extinguishing, combustion-supporting gas is isolated, and suffocation and fire extinguishing are formed, so that the fire extinguishing speed is high, the effect is good, the damage of water-soluble combustible and combustible liquid can be resisted, the modified fiber has toughness and is burning-resistant, the layered protection retention time is long, and the fire extinguishing agent can prevent re-burning after fire extinguishing in a fire scene;

2. according to the invention, bicarbonate, alkyl glycoside, coconut oil fatty acid glycol amide and imidazoline are compounded, the solubility of the bicarbonate and alkyl glycoside with the coconut oil fatty acid glycol amide and imidazoline is good, the foaming performance is also better, urea is used as a stabilizer, so that the formed foam liquid is stable, and a part of the foam liquid can be decomposed into ammonia gas after encountering fire, so that the fire can be promoted to be extinguished, the emulsifier reduces the interfacial tension of each component in a mixing system, and a firmer film is formed on the surface of a microdroplet to prevent the components from aggregating with each other, so that the mixing system is kept uniform;

3. according to the invention, the alkyl glycoside is a product which is prepared by taking glucose and natural fatty alcohol as raw materials and removing a molecule of water from hemiacetal hydroxyl and alcoholic hydroxyl under the catalysis of acid and the like, and has the advantages of good surface activity, excellent foam performance, good compatibility, no toxicity, biodegradability in percent and the like;

4. in the invention, the xanthan gum can be quickly dissolved in water, has good suspension effect on bicarbonate and emulsifier, further enables all components to be fully and uniformly mixed, has the characteristics of low concentration and high viscosity, and is also used as a thickening agent in the components, so that the adhesion effect of all components is good, and the viscosity of the foam liquid is integrally improved;

5. in the invention, the polyethylene glycol and the emulsifier are well compatible and have good dispersibility, so that the components are further uniformly mixed, and the foam liquid has good lubricity and is easy to flow out when in use;

6. the foam liquid has better sealing performance, viscosity, anti-dissolving property and stability, and has higher fire extinguishing efficiency;

7. the foam liquid has stable physical and chemical properties and does not harm animals;

8. the foam liquid contains the preservative, so that the storage time at room temperature is greatly prolonged and is more than 24 months;

9. the foam liquid contains the antifreezing agent, can be used at a lower temperature in the north or the south, and has wide application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A high-efficiency anti-burning foam liquid comprises the following components in parts by weight: 260 parts of deionized water, 0.8 part of modified cellulose, 15 parts of bicarbonate, 8 parts of surfactant, 22 parts of urea, 24 parts of foaming agent, 8 parts of emulsifier, 0.5 part of xanthan gum, 5 parts of polyethylene glycol, 1 part of antifreeze, 0.03 part of preservative, wherein the surfactant is nonionic surfactant, the emulsifier is OP-10, the antifreeze comprises ethylene glycol, the preservative comprises sodium diacetate, the foaming agent comprises alkyl glycoside and coconut oil fatty acid glycol amide, and the mass ratio of the alkyl glycoside to the coconut oil fatty acid glycol amide is 1: 1.

A preparation method of high-efficiency anti-burning foam liquid comprises the following steps:

according to the weight parts, taking deionized water (water is deionized water), heating to 36 ℃, adding an antifreezing agent and xanthan gum, fully stirring for 10min, then adding polyethylene glycol, modified cellulose and urea, fully stirring for 10min, adding a surfactant, fully stirring for 10min, adding a foaming agent, an emulsifier, a bicarbonate and a preservative, continuously stirring for 10min, wherein the stirring speed is 1800rpm, and cooling to obtain the modified cellulose;

wherein the preparation method of the bicarbonate comprises the following steps,

step 1, putting polyether glycol into a three-mouth bottle with a stirrer, a thermometer and a vacuum connecting pipe, stirring and heating, and dehydrating for 2 hours in vacuum at l10 ℃;

step 2, cooling polyether diol to 40 ℃, adding toluene diisocyanate, wherein the mass ratio of the polyether diol to the toluene diisocyanate is 1.1:1, heating to 80 ℃, starting to react, and cooling to room temperature for later use when the mass fraction of NCO is 6.8% according to the analysis and detection of a di-n-butylamine method;

and 3, spraying the reaction product obtained in the step 2, a reaction product of diethyltoluenediamine and diethyltoluenediamine in a mass ratio of 3:1 onto the bicarbonate powder by using a spraying system respectively, wherein the spraying pressure of a nozzle during spraying is 0.7MPa, the temperature is 30 ℃, the spraying amount accounts for 5% of the total sodium bicarbonate, the sodium bicarbonate powder is continuously stirred during spraying, and then the coating bicarbonate is obtained after cooling.

Example 2

A high-efficiency anti-burning foam liquid comprises the following components in parts by weight: 270 parts of water, 1 part of modified cellulose, 16 parts of bicarbonate, 10 parts of a surfactant, 25 parts of urea, 30 parts of a foaming agent, 10 parts of an emulsifier, 0.8 part of xanthan gum, 8 parts of polyethylene glycol, 3 parts of an antifreezing agent, 0.04 part of a preservative, wherein the surfactant is an amphoteric surfactant, the emulsifier is OP-10, the antifreezing agent comprises propylene glycol, the preservative comprises natamycin, and the foaming agent comprises imidazoline, alkyl glycoside and coconut oil fatty acid glycol amide in a mass ratio of 1:1: 1.

A preparation method of high-efficiency anti-burning foam liquid comprises the following steps:

according to the weight parts, taking water (water is deionized water), heating to 42 ℃, adding an antifreezing agent and xanthan gum, fully stirring for 20min, then adding polyethylene glycol, modified cellulose and urea, fully stirring for 20min, adding a surfactant and imidazoline, fully stirring for 20min, adding coconut oil fatty acid glycol amide, alkyl glycoside, an emulsifier, bicarbonate and a preservative, continuously stirring for 20min, wherein the stirring speed is 1600rpm, and cooling to obtain the modified cellulose;

wherein the preparation method of the coated bicarbonate comprises the following steps,

step 1, putting polyether glycol into a three-mouth bottle with a stirrer, a thermometer and a vacuum connecting pipe, stirring and heating, and dehydrating for 2 hours in vacuum at 113 ℃;

step 2, cooling polyether diol to 45 ℃, then adding toluene diisocyanate, wherein the mass ratio of the polyether diol to the toluene diisocyanate is 1.2:1, heating to 80 ℃, then starting to react, and cooling to room temperature for later use when the reaction time is 6.2% of NCO mass fraction according to analysis and detection of a di-n-butylamine method;

and 3, spraying the reaction product obtained in the step 2 and diethyltoluenediamine according to the mass ratio of 4:1 onto the bicarbonate powder by using a spraying system, wherein the spraying pressure of a nozzle is 1MPa, the temperature is 35 ℃, the spraying amount accounts for 6% of the total sodium bicarbonate during spraying, continuously stirring the sodium bicarbonate powder during spraying, and then cooling to obtain the coated bicarbonate.

Example 3

A high-efficiency anti-burning foam liquid comprises the following components in parts by weight: 280 parts of water, 1.2 parts of modified cellulose, 18 parts of bicarbonate, 12 parts of surfactant, 28 parts of urea, 36 parts of foaming agent, 1 part of xanthan gum, 10 parts of polyethylene glycol, 5 parts of antifreezing agent and 0.05 part of preservative, wherein the surfactant is anionic surfactant, the emulsifier is OP-10, the antifreezing agent comprises ethylene glycol, the preservative comprises sodium diacetate, and the foaming agent comprises imidazoline, alkyl glucoside and sodium dodecyl sulfate in a mass ratio of 1:1: 1.

A preparation method of high-efficiency anti-burning foam liquid comprises the following steps:

according to the weight parts, taking water (water is deionized water), heating to 44 ℃, adding the antifreezing agent and xanthan gum, fully stirring for 30min, then adding polyethylene glycol, modified cellulose and urea, fully stirring for 30min, adding the surfactant, fully stirring for 30min, adding the foaming agent, the emulsifier, the bicarbonate and the preservative, continuously stirring for 30min, wherein the stirring speed is 1000rpm, and cooling to obtain the modified cellulose;

wherein the preparation method of the coated bicarbonate comprises the following steps,

step 1, putting polyether glycol into a three-mouth bottle with a stirrer, a thermometer and a vacuum connecting pipe, stirring and heating, and carrying out vacuum dehydration for 2 hours at 115 ℃;

step 2, cooling polyether diol to 50 ℃, adding toluene diisocyanate, wherein the mass ratio of the polyether diol to the toluene diisocyanate is 1.2:1, heating to 80 ℃, starting to react, and cooling to room temperature for later use when the reaction time is 5.2% of NCO mass fraction according to the analysis and detection of a di-n-butylamine method;

and 3, spraying the reaction product obtained in the step 2 and diethyltoluenediamine according to the mass ratio of 5:1 onto the bicarbonate powder by using a spraying system respectively, wherein the spraying pressure of a nozzle during spraying is 1.2MPa, the temperature is 40 ℃, the spraying amount accounts for 7% of the total sodium bicarbonate, the sodium bicarbonate powder is continuously stirred in the spraying process, and then the coating bicarbonate is obtained by cooling.

The foam concentrate prepared in the above examples of the present application can be stored in a separate container or stored using a conventional fire fighting container. The prepared high-efficiency anti-burning foam liquid has the storage time of preferably more than 6 months, more preferably more than 12 months, more preferably more than 24 months, and most preferably more than 36 months at room temperature.

The fire-fighting container is filled with inert nitrogen, the pressure can be between 1.2 and 1.4MPa, and the pressure can also be higher, so that the container can bear higher pressure and the operation and use during fire fighting are not influenced.

The reservoir may also be a tank with a pump or pressurized gas source, provided that the tank determines that the fire suppressant can be manually or automatically dispensed through hoses and pipes, or directly from the tank, to the area of fire and surrounding areas in response to the fire. The fire fighting container material may be made of metal, polymer, carbon fiber, glass or any suitable material. These container categories include: 1) portable fire extinguisher: preferably 1 to 20 kg capacity; 2) a cart-type fire extinguisher, preferably a 20 to 300 kg capacity fire extinguisher; 3) a large fire-fighting tank mounted on the fire-fighting truck; 4) fixed storage tank and injection apparatus: fixed point fixed mounting is in the energy storage workshop, oil hazardous articles warehouse, presses close to the specific facility in conflagration danger area.

The foam liquid prepared in the embodiment of the application is tested according to national mandatory standards such as water-based extinguishing agent (GB17835-2008) and portable water-based fire extinguisher general technical conditions (GB4351-1997), and both meet the standards.

Test example 1

The foam concentrate prepared in example 1 was canned according to general technical conditions for portable water-based fire extinguishers (GB4351-1997) using a 6-liter fire extinguisher and standard spray heads and nozzles, and a fire extinguishing test was carried out by punching 1.2MPa with nitrogen and adding 10L of diesel oil to disks having a diameter of 1.2 m. The diesel oil is ignited to extinguish fire, the fire is extinguished at a distance of 3.5m from the center of the plate, and the fire extinguishing time and the burning resistant time are measured for many times.

TABLE 1 repeated tests of the foam concentrate prepared in example 1 for extinguishing diesel fires

Test example 2

The foam concentrate prepared in example 2 was canned according to general technical conditions for portable water-based fire extinguishers (GB4351-1997) using a 6-liter fire extinguisher and standard spray heads and nozzles, and a fire extinguishing test was carried out by punching 1.2MPa with nitrogen and adding 10L of alcohol to disks having a diameter of 1.2 m. The alcohol is ignited to extinguish the fire, the fire is extinguished at a distance of 3.5m from the center of the plate, and the fire extinguishing time and the burning resistant time are measured for many times.

TABLE 2 repeated tests of the foam concentrate prepared in example 2 for extinguishing alcoholic fires

Test example 3

The foam concentrate prepared in example 3 was canned according to general technical conditions for portable water-based fire extinguishers (GB4351-1997) using a 6-liter fire extinguisher and standard spray heads and nozzles, and a fire extinguishing test was carried out by punching 1.2MPa with nitrogen and charging 10L of gasoline into disks having a diameter of 1.2 m. The fire extinguishing time and the burning resistance time of the gasoline are measured by igniting the gasoline. The fire was extinguished at a distance of 3.5m from the center of the pan, and the extinguishing time and the burning resistance time were measured several times.

TABLE 3 repeated tests of the foam concentrate prepared in example 3 for extinguishing petrol fires

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.