NZ204573A - Apparatus for venting fluid from a container;vented fluid enters spray of dispersal medium - Google Patents

Description

204579 Patents Form No. 5 PATENTS ACT 1953 COMPLETE SPECIFICATION NO: 204573 DATE: 14 JUNE 1983 COMPLETE AFTER PROVISIONAL "LIQUID AND GAS VENTING APPARATUS" WE, the NEW ZEALAND FIRE SERVICE COMMISSION, a body incorporated under the Fire Service Act 1957, of Willbank House, 57 Willis Street, Wellington, New Zealand, hereby declare the invention for which we pray that a patent may be granted to us, and the 1 -7JUL1986 i 204S73 This invention relates to a method of dispersing liquids and/or gases, and more particularly to an apparatus for dispersing dangerous liquids or gases, such as liquid petroleum gas ("l.p.g." herein).

It is an object of this invention to provide a safe means for dispersing gases and liquids.

It is a further object of this invention to provide a safe and rapid means for dispersing gases and liquids.

According to this invention there is provided an apparatus for the venting of a liquid or a gas or both from a container for storing same comprising a dispersal medium supply means terminating in a spray discharge means to which is connected or which is provided with a means for supplying gas or liquid or both discharged from said container's product outlet, such that the gas and/or liquid flow stream enters the spray of the dispersal medium created by the discharge means and is broken up thereby into a readily dispersable safe, non-combustible dispersal medium-liquid/gas-air mixture.

Modifications and developments are envisaged and may be incorporated without departing from the scope or spirit of the invention.

The presently preferred embodiment relates to the dispersal of l.p.g. from cylinders by means of water as the dispersal medium.

There is observed an increasing use of l.p.g. in cylinders for use as a fuel source, particularly in motor vehicles, caravans, and the like. There is observed an increase in the storage facilities to provide for this use, including mobile and static storage containers. There is a known danger of fire should vehicles employing or carrying such containers become involved in collisions. A similar danger arises in respect to stationary storage facilities from collision, earthquake and other incidents. It has been the goal of workers to safely and rapidly vent cylinders which might otherwise risk exposure to fire. i Ours. 204573 A presently favourably employed technique is to vent cylinders by means of opening the standard venting valves of said cylinders, venting the contents either directly into the air, or by means of an outlet line, with several workers employed in dispersing the gas flow with water-hose spray nozzles, a process which may take up to eight hours for a conventional motor vehicle fuel supply cylinder. Said standard venting valve provides an outlet of much smaller diameter than the cylinder's product outlet and consequently the gas flow rate through this valve is relatively much slower.

According to the preferred embodiment, an apparatus for the venting of l.p.g. from a cylinder is provided, comprising a water supply means terminating in a spray discharge means to which is connected a means for supplying gas discharged from said cylinders product outlet such that the gas flow stream enters the spray created by the discharage means and is broken up thereby by into a readily dispersable safe, non-combustible gas-water-air mixture.

Other aspects of this invention which should be considered in all its novel aspects will become apparent from the following description, which is given by way of example of one form of the invention.

With reference to the drawing Figure 1 accompanying the provisional specification, the apparatus includes a casing 1, which is connectable by a means of connector 2 to a water supply line. Said water passes through the casing to emerge as a spray by means of the spray discharge mechanism holes 3. Mounted to the side of the casing is an attachment means 4 to which is attached the gas supply line 5. The gas passes along the gas supply means 6, and eventually emerges within the spray at aperture 7, and is dispersed as a non-combustible gas-water-mixture.

In the preferred embodiment an anti-static line has been incorporated to reduce the liklihood of a spark resulting from the build-up of static electricity with the consequent possibility of an explosion.

JUrM - A - 204573 Experimental testing has revealed that a water nozzle pressure of between 850 to 1000 kPa is most effective in safely dispersing the l.p.g. or c.n.g. Further a 70 Dm diameter water supply pipe has been found to be the optimum capacity for the users because of its weight, supply pressure capacity and power, which affect the ease of handling.

The preferred embodiment adopts the optional employment of a long gas supply means such that venting may take place for removal from the cylinder and accordingly from a potentially hazardous site, with increased safety resulting for operators, and others at the site such as accident victims.

A further feature of the invention is that it doe6 not require manning whilst in operation. Operation may therefore be exposed to potentially hazardous sites for reduced time periods.

Experiments have revealed favorable dispersal results are dependent upon maximising entrainment of the dangerous fluid with the water and air spray. Entrainment is dependent upon the spray discharge mechanism holes and characteristics. It has been found that high entrainment occurs with 3 rings of holeE with a further group of holes interspaced therebetween having the following characteristics: (I) Inner Ring 18 holes of 3.3 mm diam. each @ 27 mm "PCD" @ minus 8°. This series of holes gives a cone of water with an apex approximately 500mm from the end of the apparatus. At the apex the fingers of water forming the cone intersect. At this point the fingers collide creating an atomising effect on water beinq projected entraining gas escaping from the apparatus.

(II) Middle Ring (IIA) (Interspaced) 12 holes 3.3 mm diam. each @ 45 mm "PCD" @ plus 15°. This series of holco giv? forward and angled projection to the atomised water. 12 holes 2.2 mm diam. each @ 45 "PCD" @ plus 6°. (Inter-spaced with ring of holes No. II) series of holes gives ext forward projection and sp stream turbulence. mm 204573 (III) Outer 12 x 3.3 mm diam. each § 60 mm "PCD" § plus 6°. This series of holes are offset to holes II and IIA and give forward projection to the spray stream.

("PCD" - Pitch Circle Diameter) The arrangement of the holes in the cone is so designed to give optimum water atomisation and forward momentum of atomised water .

High pressure atomised water in the configuration formed by the cone induces air into spray and dilutes the gas to a safe level and allows rapid gas (liquid) dispersal.

Gas dispersal works on the principle that the smaller the droplet of water (spray), the greater the surface area of the mass of water passing through the cone.

Therefore the greater the surface area (per droplet), the more air (atomspheric) is entrained into the water spray. The more air, the more diluted the gas becomes, hence the gas-air mixture is below its flammability range and is safe.

The term "Pitch circle diameter" (PCD) is one well known in the art. The angle accompanying this term relates to the intersection between the axis of each bore hole and the longitudinal datum line as shown in fig 1.

The basic principle of the invention is as set forth in the statement of invention, and the Manifestation of the invention be described is intended to be by way of ezanple only.

The ends desired to be achieved mechanically may be obtained by any suitable mechanical aeans which will be well kncwn in the art.

There is additionally provided by thiB invention a method for safely dispersing a dangerous fluid comprising intimately mixing the fluid with a stream of a second fluid, preferably where the second fluid is present in an amount greater than that of the first fluid at the point of nixing.

Claims (14)

- fc - 204573 WHAT KE CLAIM IB:
1. I. An apparatus for the venting of a liquid or a gaB or both from a container for storing same comprising a dispersal medium supply means terminating in a spray discharge means to which is connected or which is provided with a means for supplying gas or liquid or both discharged from said container's product outlet, such that the gas and/or liquid flow stream enters the spray of the dispersal mediun created by the discharge means and is broken up and thereby discharaed.
2. 2. An apparatus as claimed in claim 1, in which the container is a cylinder containing pressurized liquid or gas.
3. 3. An apparatus as claimed in claim I or 2 in which the dispersal medium is water.
4. 4. An apparatus as claimed in any of the preceding claims in which the dispersal medium supply means is a 70 mm diameter hose.
5. 5. An apparatus as claimed in any of the preceding claims in which the spray discharge means comprises a spray cone with holes displayed in three rings with interspaced holes therebetween, said holes having the following characteristics: (I) Inner ring 18 holes of 3.3 mm diameter each e 27 mm "PCD" % minus 8° (II) Middle ring 12 holes of 3.3 mm diameter each % 45 mm "PCD" § plus 15° (IIA)( Interspaced) 12 holes at 2.2mm diameter each 0 45 mm diameter "PCD" 9 plus 6 (III)Outer ring 12 holes of 3.3 mm diameter each o § 60 mm "PCD" at plus 6 ("PCD" means Pitch Circle Diameter). . v V *7 JULI986 - 7 - 204373
6. 6. An apparatus as claimed in any of the preceding claims in which the said apparatus is provided with an anti-static Beans.
7. 7. A method of safely venting a liquid or a gas from a container storing same comprising connecting said container to a dispersal medium supply means terminating in a spray discharge means and discharging a dispersal medium such that said liquid or gas enters the spray produced by said spray discharge means.
8. 8. A method according to claim 1. in which the container is a cylinder containing pressurized liquid or gas.
9. 9. A method according to claim 7 or 8 in which the dispersal medium is water.
10. 10. a method according to claim 7, 8 or 9 in which the dispersal medium supply means is a 70 sun hose pipe.
11. 11. A method according to claim 7, 8, 9 or 10 in which the spray discharge means comprises a spray cone with holes displayed in three rings with interspaced holes therebetween with the following characteristics: (I) Inner Ring 18 holes of 3.3 mm diameter each § 27 mm "PCD" minus 8° (II) Middle Ring 12 holes 3.3 mm diameter each £ 45 mm "PCD" 0 plus 15° (IIA) (Interspaced) (III) Outer 12 holes 2. 2min diam. each § 45 mm "PCD" § plus 6° 12 x 3.3 mm diameter each § 60 mm "PCD" e plus 6° ("PCD" - Pitch Circle Diameter).
12. 12. A method as claimed in claim 7, 8, 9, 10 or 11 in which the apparatus is provided with an anti-static means* -r / . P-7JUL1986 0* 204573 8
13. 13. An apparatus as claimed in any one of the preceding claims whereby the gas and/or liquid flow stream enters the spray of the dispersal medium created by the discharge means and is broken up thereby into a readily dispersable noncombust-ible mixture.
14. 14. An apparatus as herein described by reference to the drawings accompanying the provisional specification. NEW ZEALAND FIfiE SERVICE COMMISSION By Its Attorneys