FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10 & rule 13]
TITLE OF THE INVENTION
LIQUID LPG WITHDRAWAL VALVE FOR LPG CYLINDERS
APPLICANT
Vanaz Engineers Limited, an Indian Company of 85/1 Paud Road, Pune 411 038, Maharashtra, India,
The following specification particularly describes the invention and the manner in which it is to be performed.

Title
"Liquid LPG Withdrawal Valve for LPG Cylinders"
Filed of Invention:
The present invention relates to a Liquid Petroleum Gas (LPG) withdrawal valve for domestic and commercial LPG cylinders. The present invention particularly relates to a Liquid Petroleum Gas (LPG) withdrawal valve which when operated withdraws Liquid LPG from a LPG cylinder and supplies it to the desired location for use. The Liquid LPG withdrawn from the cylinder can either be used directly that is in the Liquid form or it can be converted into LPG vapor in a vaporizer and then used as per the requirement depending upon the application. The Liquid LPG withdrawal valve of the present invention is suitable for multiple applications, like LPG Burners, Hot-Plates, LPG Furnaces, Stationary and Marine Engines and many other applications. The new valve is particularly suitable for such LPG Installations where there are space constraints and where LPG is consumed at much higher quantities / flow rates.
Prior Art:
At present in most of the commercial and Industrial installations, the LPG is stored in a cylinder - bank comprising a multiple LPG cylinders. On all such cylinders, the valves used are of conventional vapor withdrawal type. In such a system, the LPG is withdrawn from the cylinders in gaseous state and the vaporization takes place in the cylinder itself. As the LPG consumption increases due to higher fuel demand from the burners and / or other devices, the rate of vaporization of liquid LPG steadily increases inside the cylinders. In such a situation, the temperature of the LPG cylinder reduces to such an extent that it goes even below zero degree, thus resulting drastic reduction in the supply of gaseous LPG from the cylinder to the burners and / or other devices.


Further, due to limited capacity of LPG Vapor from each cylinder, the supply of LPG vapor and temperature of energy are also restricted. To increase this capacity two or more cylinder banks are used as per the requirement. Higher the consumption, more number of cylinders are required. This involves a lot of Storage space for the multiple cylinders in operation and additional space for storage of standby filled cylinders. Also handling of large and multiple LPG cylinders becomes inconvenient, difficult and at the same time costly. The purchase of LPG cylinders is also required to be done in large quantities which need more investment of money and thus the whole operation becomes uneconomical.
Although Liquid withdrawal valves are available in the market, they are not convenient to use for having complicated threaded outlet connections. This makes it difficult to connect / disconnect the device to down stream of valve and LPG filling Guns. Also these valves are required to be operated with ordinary hand wheel of comparatively smaller diameter and thus require a number of complete rotations of the hand wheel to operate the valves.
Therefore, one of the objects of the present invention is to mitigate the disadvantages associated with the operation of conventional and multiple LPG cylinders for both domestic and commercial purposes.
Another object of the present invention is to avoid the large storage space for the LPG cylinders and the operational difficulties due to space constraints and use of multiple LPG cylinders.
A further object of the present invention is to provide a system which would be convenient to handle a large number of multiple LPG cylinders.
A still further object of the present invention is to have a less costly and economical system of using a unit of multiple LPG cylinders in a comparatively smaller space.
One of the embodiments of the present invention is to provide a LPG withdrawal valve having a quick release coupling type outlet enabling quick and convenient


connection / disconnection of LPG device to down stream of valve and LPG filling Guns.
A second embodiment of the present invention is to accomplish the design of the valve such that the down stream device gets locked in 1st V* turn operation of the knob and after 2nd % operation of the device, the valve spindle gets depressed allowing the liquid LPG to the down stream side. For cutting of LPG supply and disconnecting the device, the operation is reversed.
In a further embodiment, the new valve consists of Excess Flow Check Valve (EFCV) fitted at the inlet. This device stops the flow of LPG incase of any breakage of LPG line on down stream of the valve.
Being Liquid withdrawal type, even a single LPG cylinder is sufficient to supply required amount of LPG to the device. Single LPG cylinder means less storage space, use of less LPG and finally low investment.
According to this invention there is provided a liquid LPG withdrawal valve for domestic and commercial LPG cylinders comprising a main body having an outlet provided with a collar suitable to form a quick release coupling with a filling gun , a LPG valve adaptor and a pressure regulator or similar device, said collar being provided with a groove in which a pawl or locking balls of said device being engaged and held firmly on said valve; an internal profile of said outlet holds a joint packing which forms a leak proof joint with said device; the lower portion of the said main body forms an inlet valve having taper threads suitable for bungs of replaceable LPG cylinders; said valve body accommodates a spindle assembly comprising a spindle , a soft gasket, a valve spindle , a spindle guide , a valve spring and an adjusting screw ; at the lower end of said main inlet body internal threads being provided to make an excess flow check valve and a dip tube
The Excess Flow Check Valve (EFCV) as described herein comprises a spring guide, EFCV body, a spring, one O-ring, a retainer and a connector. In a manner as stated hereinbelow.


The present invention will now be described in detail with reference to the accompanying drawings, wherein
Fig 1 shows a section of the new LPG withdrawal valve and
Fig 2 shows a LPG cylinder shows fitted with the new LPG withdrawal valve.
With reference to the accompanying drawings liquid LPG withdrawal valve or liquid withdrawal valve comprises a main metal body (5), a valve body (10) and an inlet body. The main body consists of an outlet having a collar adapted to form a quick release coupling with a filling gun, an LPG valve adaptor, a pressure regulator; a groove is provided in said collar for a pawl, for locking balls of said device which engages and holds firmly on said valve. Internal profile of the outlet holds a Joint Packing (20) which forms a leak proof joint with said device, the lower portion of body or Inlet Valve (25) has tapered threads suitable for Bungs (28) of replaceable LPG cylinders (29). The said valve body houses a spindle assembly consisting over Spindle (30), Soft Gasket (40) Valve Spindle (50), Spindle Guide (60), Valve Spring (70) and Adjusting Screw (80). The Lower portion or inlet of body where internal threads are provided to mount an EFCV (100) and a Dip Tube (150). The Excess Flow Check Valve consists of a Spring Guide (90), EFCV (100), Spring (110), 'O' Ring (120), Retainer (130) and a Connector (140).
A dip tube (150) of a material which is rigid enough to withstand LPG pressure and compatible with LPG with a connector (140) fitted to one end to EFCV body (100). The EFCV is further screwed into the valve body (100) from the bottom by a suitable sealant so that LPG vapor / liquid does not pass to the outlet (18) of the valve bypassing EFCV (100). The length of the tube is maintained such that it is just above the inner bottom surface of the LPG cylinder to facilitate maximum liquid withdrawal.
There is a positive Gap between the valve spindle (150) and actuating pins of Filling Gun / Adaptor / Regulator or any such device. Unless and until the knob (not shown) is rotated or the pin is physically pressed down by the actuating mechanism, the valve does not open or allow LPG or Gas to flow 'IN' or 'OUT' (as the case may be) from the LPG cylinder.


New features of the invented LPG valve of the present invention:
1. A LPG Cylinder Valve having Quick Release coupling type outlet which enables for quick and convenient connection / disconnection of LPG device and LPG Filling Gun.
2. A LPG Cylinder Valve having Outlet on which a LPG device gets locked merely by lA turn operation of the knob and next % turn operates valve spindle which gets depressed and allows liquid LPG to the downstream side for cutting off the LPG supply and disconnecting the device the procedure is reversed.
3. A valve which consists of Excess Flow Check Device fitted at the inlet. This device stops the flow of LPG in case of any breakage of LPG line on down stream of valve.
4. One more object of invention is to provide Liquid LPG Valve for a commercial cylinder which can deliver desired output LPG energy to overcome the limitations of existing vapour withdrawal type LPG cylinder valves.
5. A LPG Cylinder Valve consisting of a Dip tube at the Inlet, which will extend up to the cylinder bottom, connected to the Valve through an Excess Flow devices which will only draw Liquid LPG from the cylinder and supply it through the outlet to the downstream device.
6. A LPG Cylinder Valve which will deliver Liquid LPG at higher flow rate even with a single cylinder and have following advantages such as-
i) Occupies less storage space,
ii) Less investment in LPG.
iii) Convenient for handling.


7. A LPG Cylinder Valve consisting of a Metallic Valve Body manufactured by a suitable process which will withstand high pressure of LPG, having material compatible with LPG, also wear resistant external surface to bear tightening torque / wrenching forces, clamping and operating forces of LPG filling Gun and other devices and in addition house a valve spindle sub-assembly which automatically cuts LPG supply to the outlet once the down stream LPG device knob is turned off/ or device disconnected.
8. One more object is to provide a LPG cylinder Valve having "Inlet" with Gas tight threads suitable for a standard LPG cylinder bung available in market.
The improved features of the new valve are:
1) To facilitate an outlet suitable for quick release coupling joint with a standard LPG device.
2) To support Excess Flow Check Valve assembly which automatically closes the LPG liquid supply once the pressure difference exceeds certain limit.
3) To hold dip tube inside the cylinder which will dip into the liquid LPG upto the bottom of cylinder and form a leak tight joint between inner and external portion of tube and allow only liquid LPG withdrawal.
4) To house a self closing valve pin assembly having a soft seal balanced by spring against metallic valve body to make a leak proof joint.
5) To provide a body with sufficient strength supporting all devices mentioned above and also makes a leak proof joint with the cylinder bung threads.


The entire Valve assembly with dip tube and excess flow check valve are inserted through the cylinder bung into cylinder. The size of excess flow check valve and tube are smaller than the hole of the cylinder bung to facilitate easy insertion of both.
The valve body is screwed on to the bung of cylinder and tightened at a suitable torque with a torque wrench on Hexagonal portion provided on the body. Before screwing a Teflon tape is applied to the valve threads so that the valve to cylinder joint is perfectly leak proof.
Working of the Liquid Withdrawal Valve
Filling of LPG through this valve :-
> In case of Filling, the standard LPG Filling Gun is provided with two-step
mechanism.
1) First Mechanism is to hold the valve in position firmly forming a Leak proof joint with valve outlet.
2) Second Mechanism is to depress the valve pin physically to open the liquid flow path and simultaneously force pressurized LPG liquid into the cylinder through the valve.
> In case of other down stream Devices to be used with inverted valve, the
above two arrangement are provided in such devices like LPG Adaptor or a
Regulator. However, the only difference here is that with the operation of
knob the valve pin is depressed to open and allow the LPG / Liquid to flow
from the cylinder to the point of use / device.
Filling of LPG through this valve:-
1) The standard LPG filling Gun with its quick release coupling mechanism couples with the valve outlet and holds the valve firmly. Due to the presence of packing washer, the joint is perfectly leak proof.


2) With the Gun Mechanism, the valve spindle is depressed and simultaneously liquid LPG is forced into the LPG cylinder through the valve opening.
3) Once the filling is complete, the valve pin and the valve are released. As soon as the valve pin is released, it takes back its seat and cuts off any flow of LPG into or out of the cylinder.
LPG Withdrawal:-
The standard device LPG Adaptor, or Previous Regulator have quick release mechanism operated by a rotating V2 turn knob. During final lA turn the device couples with the valve outlet and holds onto the valve firmly making a leak proof joint. During next V* turn operation of knob it depresses the valve pin and opens the valve port to allow LPG through it to the downstream devices.


We Claim.-
1. A liquid LPG withdrawal valve for domestic and commercial LPG cylinders comprising a main body (5) having an outlet (10) provided with a collar suitable to form a quick release coupling with a filling gun , a LPG valve adaptor and a pressure regulator or similar device, said collar being provided with a groove in which a pawl or locking balls of said device being engaged and held firmly on said valve; an internal profile of said outlet holds a joint packing (20) which forms a leak proof joint with said device; the lower portion of the said main body forms an inlet valve (25) having taper threads suitable for bungs (28) of replaceable LPG cylinders (29); said valve body accommodates a spindle assembly comprising a spindle (30), a soft gasket (40), a valve spindle (50), a spindle guide (60), a valve spring (70) and an adjusting screw (80); at the lower end of said main inlet body internal threads being provided to make an excess flow check valve (100 ) and a dip tube (150).
2. A liquid LPG withdrawal valve as claimed in claim 1 wherein said excess flow check valve comprises a spring guide (90) excess flow check valve body (100), a spring (110), one O-ring (120), a retainer (130) and a connector (140).
3. A liquid LPG withdrawal valve as claimed in claim 1 or 2 wherein said dip tube (150) is made of a material rigid enough to withstand LPG pressure and compatible with LPG connected with a connector (140) fitted at one end of excess flow check valve body (100).
4. A liquid LPG withdrawal valve as claimed in claim 3 wherein said dip tube is connected to the valve body through excess flow check valve as per the requirement and joined to the connector by suitable means.
5. A liquid LPG withdrawal valve as claimed in claim 3 or 4 wherein said excess flow check valve is further screwed to the valve body from the bottom to form a liquid / gas tight joint.


6. A liquid LPG withdrawal valve as claimed in claim 5 wherein said excess flow check valve and the valve body are joined with a sealant so that LPG vapour / liquid gas does not pass to the outlet of valve bypassing said excess flow check valve.
7. A liquid LPG withdrawal valve as claimed in any of the preceding claims wherein the length of said tube is maintained such that it is placed just above the inner bottom surface of the LPG cylinder to facilitate maximum liquid withdrawal.
8. A liquid LPG withdrawal valve for domestic and commercial LPG cylinders substantially as herein described with reference to the accompanying drawings.


ABSTRACT OF THE INVENTION
A liquid LPG withdrawal valve for domestic and commercial LPG cylinders. The valve comprises of a main body (5) having an outlet (10) provided with a collar suitable to form a quick release coupling with a filling gun, a LPG valve adaptor and a pressure regulator or similar device. The collar is provided with a groove in which a pawl or locking balls of said device is engaged and held firmly on said valve. An internal profile of said outlet holds a joint packing (20) which forms a leak proof joint with said device; the lower portion of the said main body forms an inlet valve (25) having taper threads suitable for bungs (28) of replaceable LPG cylinders (29). The valve body accommodates a spindle assembly comprising a spindle (30), a soft gasket (40), a valve spindle (50), a spindle guide (60), a valve spring (70) and an adjusting screw (80); at the lower end of said main inlet body internal threads being provided to make an excess flow check valve (100) and a dip tube (150)
Fig.l