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(11) | EP 1 443 263 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Liquefied gas vaporizer |
| (57) The invention is a new liquefied gas vaporizer (V) suitable for application to tanks
(S), comprising a vertical cylinder (1), closed at the ends, complete with an on/off
valve (3) for the gas in the liquid state, a heat exchanger unit (4), fittings and
connections (5) for drawing off the gas in the gaseous state, for serving the heat
exchanger unit (4) and for attaching accessories (6). The heat exchanger unit (4)
transmits the amount of heat needed to vaporize the gas and, depending on the demand
of gas in the gaseous phase, the actuator controls the on/off valve (3) to regulate
the collection of further quantities of liquid gas. The only liquid gas that is heated
is the amount collected and contained inside the cylinder (1) of the vaporizer (V). |
[0001] The present patent regards tanks for liquefied gas and devices for the vaporization of liquid gas and its collection in gaseous form.
[0002] Liquefied combustible gas is used in many applications, stored in a liquid state in a suitable tank and vaporized to restore it to a gaseous state for final use.
[0003] At present, tanks for storing liquefied gas are basically made to contain the gas in a liquid state, while vaporization to the gaseous state is done by a specific device positioned outside the tank, called vaporizer, connected to the tank by means of one or more conduits.
[0004] Current vaporizers comprise a casing with a heat exchanger. The liquid gas is fed to the vaporizer through a valve and heated by the exchanger to a preset temperature, thereby rapidly changing into its gaseous state. The gas in its gaseous state is drawn off through a suitable conduit located in the casing, preferably on its upper wall.
[0005] The heat exchanger can be an electric heating element or a fluid circuit heated by a different source.
[0006] The system comprising separate tank and vaporizer connected by conduits has a number of drawbacks and disadvantages.
[0007] The tank and vaporizer are two separate objects, each of which occupies a certain amount of space and has certain installation and servicing requirements.
[0008] The necessary connections have to be provided between tank and vaporizer; said connections can be a source of malfunctions or problems with the delivery of the gas in its gaseous state or with the transfer of the gas to the vaporizer when it is still in its liquid state.
[0009] To avoid all the above disadvantages, a new liquefied gas vaporizer device suitable for application to tanks has been designed and developed.
[0010] The aim of the new vaporizer device is to avoid the disadvantages that occur when the liquid gas is fed to the vaporizer.
[0011] Another aim of the new vaporizer device is to enable a faster and readier flow of liquid gas to the vaporization chamber.
[0012] Another aim of the new vaporizer device is to enable a continuous and stable output of gas in the gaseous state.
[0013] These and other direct and complementary aims are achieved by the new liquefied gas vaporizer suitable for application to tanks, comprising a vertical cylinder, closed at the ends, complete with an on/off valve for the gas in its liquid state, and containing a heat exchanger fitted at the top with one or more pressure reducers, fittings and connections for drawing off the gas in its gaseous state, for powering the heat exchanger and for attaching accessories such as pressure gauges, thermometers, flushing valves and so on.
[0014] A connection ring is located on the outside, near the top end of the cylinder, for attaching the new vaporizer to the liquefied gas tank or to a specific support alongside said tank.
[0015] The fittings and connections for collecting the gas in its gaseous state and the heat exchanger are fixed or attached to a removable flange fixed to the top end of the cylinder to enable access, inspection and maintenance on the various parts of the new vaporizer without having to completely remove the new device's cylinder and without having to empty the tank.
[0016] The heat exchanger unit can comprise a heat exchanger body (evaporator) with two separate circuits inside, one for the heated fluid and one for the gas to vaporize (direct heating) or, more simply, a coil containing the heated fluid (direct heating), a coil containing a heating element (direct heating), or a tube containing a diathermal fluid and a coil containing the heated fluid or a heating element (indirect heating).
[0017] The characteristics of the new vaporizer suitable for application to liquefied gas tanks will be better clarified by the following description, with reference to the attached drawings, provided only as an illustrative and not restrictive example.
[0018] Figure A is a functional diagram where (Il) indicates the liquefied gas inlet conduit, (R) is the pressure reducer, (Ig) is the conduit for drawing off gas directly from the tank, (Uu) is the conduit for delivering the gas ready for use, (Ai and Au) are the heating water/glycol inlet and outlet.
[0019] Figure la shows a view of the new vaporizer (V) complete with a vertical cylinder (1) with two end flanges (2s, 2i), one on/off valve (3), a heat exchanger unit (4), fittings and connections (5, 6) in the design solution with the on/off valve installed at the bottom.
[0020] Figure 1b shows a partial view of the new vaporizer (V) complete with a vertical cylinder (1) with end flange (2s), the reducer (R), inlet and outlet conduits for the heating fluid (Ai, Au), a flange (fu) for connection to the utility point and a flange (f3) for the on/off valve (3), in the design solution with the on/off valve at the top.
[0021] The vertical cylinder (1) is preferably made of metal and has two rings (1.1s, 1.1i) at the ends for attaching the upper (2s) and lower (2i) flanges if the latter is not welded directly onto the cylinder (1).
[0022] A third ring (1.1a) is provided in the vicinity of the top end of the cylinder (1) to enable the connection and fixing of the new vaporizer (V) to the tank (S).
[0023] In the top part of the cylinder (1), between the upper ring (1.1s) and the intermediate ring (1.1a), there will be auxiliary connections (6) for accessories such as a pressure gauge, thermometer, flushing valve, etc.
[0024] The top and bottom ends of the cylinder (1) are closed by the upper (2s) and lower (2i) flanges.
[0025] In the design solution with the on/off valve at the top, the lower flange (2i) comprises a metal disc welded directly onto the lower end of the cylinder (1).
[0026] Whenever said on/off valve (3) is located at the lower end, it is automatically controlled by an actuator (3.1) applied to the upper flange (2s) and connected by means of a bar (3.2) positioned inside the cylinder (1), as shown in Figure 3.
[0027] The on/off valve (3) regulates, enables or disables the flow of liquefied gas inside the device, in order to ensure that only gas in the gaseous state generated inside the vaporizer's cylinder (1) can be drawn off, preventing any accidental delivery of gas in the liquid phase.
[0028] The upper flange (2s) is made of a metal disc suitable for fixing in a removable manner to the upper ring (1.1s) on the cylinder (1), where the following are attached: the heat exchanger unit (4) with its water/glycol inlet and outlet connections (Ai and Au), the fitting or connection for drawing off gas in the gaseous phase (Uu), inlets for gas in the liquid phase (Il) and in the gaseous phase (Ig) from the tank and, where applicable, the valve (3).
[0029] The heat exchanger unit (4) is made of linear piping or, preferably, of a vertical coil (4.1) that can be fitted inside the cylinder (1), reaching down to the lower zone.
[0030] Said coil (4.1) or piping of the heat exchanger unit (4) has suitable inlet and outlet fittings (4.2) on the top surface of the upper flange (2s).
[0031] A diathermal nonflammable fluid (typically water or a water-glycol solution) flows inside said heat exchanger coil (4.1) or linear piping at a predefined temperature of approximately 50°C.
[0032] The diathermal fluid is heated by an external unit connected with the inlet and outlet fittings (4.2) on the top surface of the upper flange (2s).
[0033] Said heat exchanger coil (4.1) or linear piping may also include an electric heating element with electrical power contacts in line with the fittings (4.2) of the coil (4.1) or linear piping on the top of the upper flange (2s).
[0034] Figure 2 shows an alternative design solution in which the coil (4.1) or linear piping of the heat exchanger unit (4) is enclosed in an intermediate chamber (4.3) containing a fluid that is in turn heated by the coil itself.
[0035] The above-described new vaporizer (V) can be attached to the liquefied gas tank (S) as shown in Figure 4, or to the side of the tank (S).
[0036] The above-described new vaporizer (V) can be a separate element attached to the tank (S) by means of nuts and bolts that fix the intermediate ring (2a) to an appropriate flange, or it can be welded to the tank (S) to become an integral part of a single device for containing liquefied gas and delivering gas in the gaseous state.
[0037] When the above-described new vaporizer (V) is in operation, the liquefied gas is collected from the tank (S) through the open on/off valve (3). The liquefied gas is fed to the device according to the demand for collection of gas in the gaseous phase and the control system governs the valve (3) to guarantee the required balance.
[0039] Only the liquid gas collected and contained inside the cylinder (1) of the vaporizer (V) is heated.
[0041] The overall dimensions are reduced, since the vaporizer (V) is incorporated or at least included in the overall dimensions of the tank (S).
[0042] In the event of the pressure in the tank exceeding the threshold value set in the valve (Ig), the gas is delivered directly through this valve, drawing it in the gaseous phase directly from the tank and thereby excluding the heat exchanger.
[0045] Heat exchange only affects the gas contained inside the vaporizer (V), without affecting the contents of the tank (S).
1. Liquefied gas vaporizer suitable for application to tanks, characterized in that it comprises a vertical cylinder (1), closed at the ends, complete with an on/off
valve (3) to regulate the flow of gas in the liquid phase to the vaporizer (V), complete
with fittings and connections (5) at the top for drawing off the gas in the gaseous
state, and complete with a heat exchanger unit (4) inside, and wherein said vertical
cylinder (1) is suitable for being inserted inside liquefied gas tanks.
2. Vaporizer according to claim 1, characterized in that the flow of gas leaving the reducer is obtained from the vaporization of the liquid
phase coming from the conduit (Il) by means of a heat exchanger, or directly from
the vapor phase coming from the conduit (Ig), depending on the pressure existing inside
the tank.
3. Vaporizer according to claims 1 and 2, characterized in that said on/off valve (3) is located on a top flange (2s) positioned on said vertical
cylinder (1), and wherein said on/off valve (3) is connected to a conduit with an
outlet in the vicinity of the bottom of said tank.
4. Vaporizer according to claims 2 and 3, characterized in that both the couplings for delivering the liquid and gaseous phases coming from the storage
tank are inserted in the vaporizer.
5. Vaporizer according to the previous claims, characterized in that the heat exchanger unit comprises a heat exchanger body in which the heated fluid
and the gas to vaporize flow in two separate circuits.
6. Vaporizer according to the previous claims, characterized in that the vertical cylinder (1) is such that said on/off valve (3) is situated near the
bottom of the tank (S) and that the fittings and connections (5) for drawing off the
gas in the gaseous state are on the outside at the top of the tank (S).
7. Vaporizer according to the previous claims, characterized in that the heat exchanger unit (4) is made of practically vertical and linear piping, or
of a vertical coil (4.1) located inside the cylinder (1) and complete with inlet and
outlet fittings (4.2) at the top end of the cylinder (1) and on the outside of the
tank (S), and wherein a diathermal and nonflammable fluid heated to the appropriate
temperature circulates inside said coil (4.1) or linear piping.
8. Vaporizer according to the previous claims, characterized in that the heat exchanger unit (4) is made of practically vertical and linear piping, or
of a vertical coil (4.1) located inside the cylinder (1), and wherein inside said
coil (4.1) or linear piping there is an electric heating element with the electrical
contacts on the top end of the cylinder (1), on the outside of the tank (S).
9. Vaporizer according to the previous claims, characterized in that said coil (4.1) is also in the lower part of the cylinder (1).
10. Vaporizer according to the previous claims, characterized in that said coil (4.1) or linear piping of the heat exchanger unit (4) is enclosed in an
intermediate chamber (4.3) containing a fluid that in turn is heated by said coil
(4.1).
11. Vaporizer according to the previous claims, characterized in that the top end of the cylinder (1) is closed by a removable upper flange (2s), and wherein
the heat exchanger unit (4) is fixed or at least connected to said removable upper
flange (2s).
12. Vaporizer according to the previous claims, characterized in that the bottom end of the cylinder (1) is closed by a lower flange (2i), and wherein
the on/off valve (3) is attached to said removable lower flange (2i).
13. Vaporizer according to the previous claims, characterized in that said on/off valve (3) is automatically controlled by a pneumatic-thermostatic actuator
(3.1) attached to the upper flange (2s) and connected to said valve (3) by means of
a bar (3.2) inside the cylinder (1), and wherein said on/off valve (3) is preferably
of the electronic, thermostatic, mechanical type.
14. Vaporizer according to the previous claims, characterized in that the top end of the cylinder (1) on the outside of the tank (S) and/or the removable
upper flange (2s) have auxiliary connections (6) for accessories, such as pressure
gauges, thermometers, flushing valves etc.