CN1084204A - dry powder compressed aerosol - Google Patents

Abstract

A dry powder aerosol product comprising:

an aerosol canister comprising a valve and an ejector device and, when required, a cannula; a quantity of dry hydrophobic powder in the aerosol canister; and an inert gas at a pressure of at least 620kPag (20 ℃).

Description

The present invention relates to dry powder compressed aerosol products and to methods and apparatus for making the same, particularly but not limited to fire extinguishing aerosol products.

For many years, people have hoped for a dry powder aerosol product that does not use organic propellants, is non-toxic to the human body, and does not harm the environment. However, this wish has not been realized so far. Although dry powder aerosol products sprayed with compressed inert gas are considered ideal, a product with satisfactory formulation, product stability, shelf life, and spray particle fineness has not yet been produced. dry powder aerosol products, and have not been able to develop a method and equipment for producing such products.

U.S. Patent Nos. 3,055,435 (Warnock), 2,065,818 (Carter), and 2,819,763 (Boal) deal with the use of compressed gases (such as nitrogen, carbon dioxide, or air) and, somewhat surprisingly, B A dry chemical extinguisher (unlike a canned aerosol product) that uses alkane to spray the dry chemical out of the extinguisher. These patents specifically describe the use of a valve arrangement and the use of sorbents to facilitate the discharge of fire suppression chemicals. No one patent mentions these problems of producing a kind of canned aerosol dry powder fire extinguishing product. U.S. Patent No. 2,785,838 (Mayer) proposes a canister type dry powder aerosol fire extinguisher, and presents a problem associated with such a device, which is provided with a valve plug at one end of the intubation tube, when required When the valve mechanism on the canister is manipulated to allow the contents of the canister to be ejected, the valve stopper opens the cannula to allow the powder to flow out. The patent specifically mentions the use of liquefied gas products such as dichlorodifluoromethane instead of compressed gases such as nitrogen, and specifically how to solve the problem of powder being wetted by liquefied gas propellant and forming lumps, because the lumps Blocks can completely block the valve mechanism and nozzle of the aerosol can, thus rendering it inoperable effectively.

"Principles of Aerosol Technology", Paul A. Sanders, 1990, Van Nostrand Reinhold Company PP28-33, 60-62, 88-90 and 161-163; "The Science and Technology of Aerosol ard Packaging", John S. Sciarra and Leou Stoller, 1974, John Wiley & Sons, PP136-141; and "Kirk Othmer Encyclopaedia of Chemical Technology", Vol. The potential use of compressed gas propellants for sol cans is so enthusiastically welcomed because of the advantages of nitrogen's cheapness, low toxicity, inertness and stability. However, nitrogen is still basically rejected, mainly because it is difficult to eject all the powder product when the compressed gas is only charged to a pressure of 690kPag (at 20°C). When the tank is turned upside down for spraying in an unexpected situation, the compressed gas can only be sprayed to a certain extent, and the remaining gas is not enough to spray all the powder product. The use of compressed gas in all respects has therefore been largely abandoned.

Although there has been a strong demand in recent years to rapidly reduce global emissions of those gases that cause greenhouse effects and gases that deplete the ozone layer (such as liquefied gases including hydrocarbons, halocarbons, or halogenated hydrocarbons), there is still no satisfactory Known or available dry powder compressed aerosol products have the potential to be used in a wide range of areas and to deliver powder products over long distances in an acceptable spray pattern.

It is therefore an object of the present invention to provide a compressed gas dry powder aerosol product which can be used in a wide range of applications, including fire fighting, and to provide a method and apparatus for the manufacture of such a product.

Therefore one aspect of the present invention provides a kind of method for the manufacture of dry powder aerosol product, the method comprises:

Fill the desired amount of dry hydrophobic powder into an aerosol can;

A valve and injector assembly, with cannula when required, is fitted to the tank in such a way that the valve and injector assembly do not come into contact with the dry powder and the injector assembly's cannula does not protrude into the dry powder .

Invert the jar to ensure that the open end of the cannula does not stick to the powder; and

Pressurize the tank to at least 620 kPag (20°C) with inert gas at the filling station.

On the other hand, the present invention also provides a kind of dry powder aerosol product, and this product comprises:

an aerosol can, which includes a valve and injector assembly and, when required, a cannula;

A measure of dry hydrophobic powder in an aerosol can; and

An inert gas propellant with a pressure of at least 620 kPag (20°C).

Preferably the dry powder contains ammonium ammonium phosphate and the gas is nitrogen. The preferred pressure is at least 690 kPag and the most preferred pressure is 840-1000 kPag (20°C). The canister most preferably used is one having a nominal volume of 550, 670 or 1,400ml and the amount of dry powder in the canister is about 300, 370-420 (preferably 400) or 1,000g respectively. For the nominal volume of 670ml, the weight of the gas introduced is preferably about 5.0-5.6g, preferably 5.3g, while for tanks of other volumes the weight of the gas introduced is adjusted accordingly, for example 4.1-4.6, most preferably Preferably 4.35g (for 550ml nominal volume), and 10.4-11.7, preferably 11.1g (for 1400ml nominal volume).

It is best to cut off the gas passage between the tank and the filling table before opening and closing the gas flow, so as to ensure that the valve device on the tank is closed before the pressure drop caused by closing the gas flow, so that any dry powder can be practically prevented Cannula into the valve unit and possible resulting blockage and subsequent interruption of gas flow and product flow during injection.

The Australian Standard AS2278-1986 formulated by the Standards Associatoin of Australia for metal aerosol containers should be consistent with the following minimum deformation pressure standards:

1. The low-pressure container (tinplate container with welded seam) must be able to withstand the pressure of 970kPag (55°C);

2. The medium pressure container (the overall aluminum container) must be able to withstand the pressure of 1100kPag (55°C);

3. High-pressure containers must be able to withstand a pressure of 1265kPag (55°C); this standard applies to containers with an inner diameter less than or equal to 75mm and a nominal (full) volume less than or equal to 820ml.

The above preferred method is based on those aerosol cans meeting the minimum Australian Standards for low and medium pressure containers. It will be appreciated that if the tank used is capable of withstanding a pressure in excess of the minimum standard corresponding to minimal deformation, then the nitrogen pressure can be increased accordingly. For example, if a low-pressure tank can withstand a pressure of 1150 kPag without deformation, the nitrogen pressure can be increased to 1000 kPag (20°C), which is much higher than suggested by the prior art.

The above inflation pressures are determined according to the pressure/temperature relationship table below for compressed gases (including nitrogen).

Temperature (°C) Pressure (kPag) approximate value

10 500 960

20 521 1000

30 542 1040

40 564 1080

50 585 1120

55 596 1140

It will be readily appreciated that the method and apparatus of the present invention are applicable to the provision of a wide range of dry powder compressed aerosol products by incorporating a suitable powder carrier carrying the particular active ingredient desired.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing, which shows a plan view of an apparatus for carrying out the method of the invention.

The aerosol cans (valve and sprayer not yet installed) are placed on the automatic stacking station 10 and transferred to the product feeding station 11, where the canister is filled with a finely powdered phosphoric acid from the product reservoir 12 The product FUREX710 with ammonium hydrogen as the main component has a loading capacity of about 400g. The tank is then transferred to the valve and injector mounting station 13 where the valve and injector assembly is inserted into the tank at an angle to the tank so that the valve and injector assembly is inserted into the tank and secured to the tank The combination of the valve's cannula and the injector does not adhere to the product. The tank is then transferred to the filling station 14, where the tank is filled with nitrogen to a pressure of 840kPag. During inflation, the tank should maintain an angle of at least 45° with the vertical. The tank is then sent to a valve button (Valve button) mounting station 15, then to a capping station 16 and finally to a storage station 17. Before and after filling, weigh at stations 18 and 19 respectively to check that the required amount of gas has been filled into the tank.

It is also possible to set up an additional weighing station to check the weight of the added powder. The following table gives the test situation on a batch of 24 cans filled with flame retardant material and nitrogen.

surface

A Empty tank weight (g)

B Tank and product weight (g)

C Closed tank weight (g)

D Tank weight after inflation (g)

E Final tank weight (starter and cover installed)

Empty tank weight change range 100.8-102.2＝1.4g

Gas weight change range (D-C) 5.2-5.4g

Powder weight change (B-A) 379.6-385.6g, average range 6g

Average combined weight of starter and cover 10.6-10.8g

A particularly preferred flame retardant material is FUREX 710 produced by Chemishe Produkte Weinstock & Siebert (Dusseldorf, Germany), which is based on ammonium hydrogen phosphate with additives such as stabilizers, hydrophobicity enhancers and anti-caking agents. Block of fire extinguishing powder.

It will be readily understood that the method of the present invention can be applied to a wide variety of hydrophobic powder aerosol products, and the present invention is not limited to dry powder fire extinguishing aerosol products. It will be readily understood that the dry powder aerosol product of the present invention may be made from any finely divided, hydrophobic, free-flowing powder.

Claims (13)

1, a kind of method of making the dry powder aerosol product, this method comprises:

The dry hydrophobic powder of aequum is packed in the aerosol canister;

With a valve and injector device, when needs, also comprise intubate, be installed on the jar, will make valve not contact during installation, and the intubate of injector device is not inserted in the powder with powder with injector device;

Tilt this jar with the opening end that guarantees said intubate adhering powder not; And

Jar is pressurized to the pressure that is at least 620kPag (20 ℃) at the inflation platform with rare gas element.

2, method as claimed in claim 1, wherein said powder packets phosphoric acid hydrogen ammonium.

3, as the method for claim 1 or 2, wherein said gas is nitrogen.

4, as claim 1,2 or 3 method, wherein said pressure is at least 690kPag.

5, method as claimed in claim 4, wherein said pressure is 840-1000kPag(20 ℃).

6, method as claimed in claim 5, wherein said jar is that a kind of nominal volume is 550,670 or 1, the jar of 400ml, the dry powder amount in jar then is respectively 300,370-420(is preferably 400) or 1000g.

7, method as claimed in claim 6, the wherein said weight that charges into gas is the jar of 550ml for nominal volume, is approximately 4.1-4.6g, is preferably 4.35g; Jar for 670ml is approximately 5.0-5.6g, is preferably 5.3g; For 1, the jar of 400ml is approximately 10.4-11.7g, is preferably 11.1g.

8, method as claimed in claim 7, wherein, to guarantee causing that owing to the closed gas flow valvegear on the jar has been in closing condition before the remarkable decline of pressure, enter the intubate and the obstruction and the interruption of gas stream and product flow in course of injection afterwards that therefore cause of valvegear in the gas passage between elder generation's cut-out jar before the closed gas flow and the inflation platform in fact to prevent any dry powder.

9, a kind of dry powder aerosol product, it comprises:

An aerosol canister, it comprises a valve and injector device, also comprises an intubate when needs;

Be in a certain amount of dry hydrophobic powder in the aerosol canister; And a kind of at 620kPag(20 ℃ at least) rare gas element propellant under the pressure.

10, product as claimed in claim 9, wherein said powder packets phosphoric acid hydrogen ammonium, and said gas is nitrogen.

11, as the product of claim 9 or 10, wherein said pressure is 690kPag(20 ℃ at least), and most preferably be 840-1000kPag(20 ℃).

12, as claim 9,10 or 11 product, wherein said jar is that a kind of nominal volume is 550,670 or 1, jar of 400ml, the amount of powder in the jar then is respectively 300g, 370-420(is preferably 400) g, or 1,000g.

13, as the product of claim 12, the wherein said weight that charges into gas, the jar for the 550ml nominal volume is approximately 4.1-4.6g, is preferably 4.35g; Jar for the 670ml nominal volume is approximately 5.0-5.6g, is preferably 5.3g; For 1, the jar of 400ml nominal volume is approximately 10.4-11.7g, is preferably 11.1g.