MXPA01004600A - Thermostatically controlled heater for gas fuel and gas pressure regulator - Google Patents

Abstract

A heater for gas fuel mounted to a pressure reducing regulator to warm the gas after the temperature is reduced by the pressure reduction. The heater receives the fuel from the regulator through an external pipe and has separate gas and coolant passages therein. The coolant passage receives liquid engine coolant that heats both the gas and the regulator. A heater core has a plurality of radially extending fins around which the gas passes with the coolant passing through the interior of the core. Coolant flow is regulated by a thermostat that is responsive to the temperature of the gas to open and close the coolant passage.

Description

THERMOSTATELY CONTROLLED HEATER FOR FUEL GAS AND GAS PRESSURE REGULATOR BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a fuel gas heater and in particular to a heater mounted to a gas regulator and having a thermostatic control that responds to the temperature of the gas to control the flow of the engine cooler through the heater. 2. Description of the related art Compressed natural gas, when used as a fuel vehicle, is stored at very high pressures, typically greater than 3,000 pounds per square inch. The engine of the vehicle can not use the fuel at this high pressure. Therefore, a pressure reduction regulator is necessary to lower the fuel gas pressure. A single-stage regulator is more desirable than a multi-stage regulator because of the simplicity of its design. During the reduction of the pressure, while the gas expands, the temperature of the gas decreases. This expansion of the gas can give gas temperatures near or below -100 ° C. This cooling effect of the gas is most noticeable in the design of the single-stage regulator. The single-stage regulator manufactured by ITT Conoflow is designed to expand the gas outside the regulator body so that the regulator itself is not subject to the extreme cold of the gas that expands.

The fuel gas measuring valve in the engine must have gas at a temperature above -40 ° C and preferably above 0 ° C to prevent freezing of any moisture in the fuel line. When this pressure reduction regulator is used in close proximity to the engine, there is insufficient ambient gas heating in the fuel line connecting the regulator to the metering valve in the engine to heat the fuel to the desired temperature. A heater is required to raise the temperature of the expanded gas above the minimum temperature required by the fuel metering valve.

Synthesis of the invention The present invention provides a natural gas heater that is thermostatically controlled. The heater housing is attached to the regulator body. The heater is connected to the engine cooling system and receives the engine cooler flowing through a cooling duct in the heater. The heater has a gas conduit in it with a gas inlet and outlet. The gas inlet of the heater is in communication with the gas outlet of the regulator by means of an external pipe.

The heater box is cylindrical and has a core in it that separates the conduits from the cooler and from the gas. The core includes a cylindrical wall having fins extending radially outward in the gas conduit and fins extending radially inwardly in the cooling conduit. The fins that extend outward are truncated at alternating axial ends, which form a serpentine gas conduit around the fins. The cylindrical box has a gas inlet and a gas outlet circumferentially spaced apart from one another. _ A pair of fins separate the gas inlet from the gas outlet, which provide an insulating air gap between the inlet and outlet.

The motor cooler flows through the center of the core to provide heat to the core and fins that extend radially outward in the gas conduit. A thermostat is provided to close the chiller duct when the gas is overheated. The thermostat is controlled by a reservoir of wax located in the gas conduit adjacent to the gas outlet. The thermostat therefore responds to _aM - ^^ j ^ _ ^ _ ^^^^^ M ^ M ^^^^^^^^^^^^^^^^ ip ^^^^^ iifi §rf ? ^ É ^? the temperature of the gas to open and close the cooling duct.

Since the heater is mounted externally to the regulator body as opposed to being integrally formed with the regulator body, if the regulator is used in a vehicle configuration where sufficient heat from the combustible gas environment is available between the regulator and the engine, The heater can simply be removed and the fuel line to the engine is fastened to the gas outlet of the regulator body.

In preferred embodiments, the fuel gas is regulated to 110 inches per square pound or 120 inches per square pound and is heated to about 32.22 ° C (90 ° F). The heater of the present invention can be used with gaseous fuels instead of natural gas that are stored under high pressure and are excessively cooled when the pressure is reduced in a single stage regulator.

Description of the drawings Figure 1 is a schematic diagram of the natural fuel gas system.

Figure 2 is a perspective view of the regulator and gas heater of the present invention.

Figure 3 is an enlarged perspective view of the regulator and the gas heater shown in Figure 1.

Figure 4 is a sectional view as seen from line 4-4 of Figure 2.

Figure 5 is a sectional view as seen from line 5-5 of Figure 2.

Figure 6 is a sectional perspective view of the end head of the heater box.

Figure 7 is an enlarged perspective view of the heater core.

Figure 8 is a sectional view of the heater core with the fins removed.

Figures 9 and 10 are end and side views of a fin of the heater core.

Description of the Preferred Incorporation The heater 10 of the present invention is shown in Figure 1 in a fuel system of a vehicle. The fuel system includes a fuel tank 12, a pressure regulator 18 and the heater 10 for supplying fuel gas, such as natural gas to a motor 14. The engine 14 has a cooling system that includes a radiator 16 connected to the motor through hoses 19 and 21 in a conventional manner for a liquid-cooled motor. The heater 10 is mounted to the body 36 to the pressure regulator 18. The regulator 18 receives high pressure fuel gas from the tank 12 via a fuel line 20. The regulator 18 reduces the pressure of the gas leaving the regulator 18. As a result of the drop in gas pressure, the temperature of the gas is reduced. The cooled gas travels through an external tube 22 from the outlet of the regulator to the gas inlet of the heater 10. After being heated in the heater 10, the gas travels through the fuel line 24 to a metering valve 26 in the engine 14. A fuel line 28 directs the fuel from the valve 26 to the engine. The cooler of the engine cooling system is provided to the heater through a cooling line 30 and is returned to the engine cooling system through of a cooling line 32. ^^^^^^^^^^^^^^^^ t ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^? ^^^^^^^^ j ^^^^^ g ^ g ^^^ With reference to Figures 2-5, the heater is shown in greater detail. The heater 10 is shown mounted to the regulator 18. The regulator 18 includes a body 36 having a gas inlet 38 and a gas outlet 40. The regulator is preferably an ITT Conoflow regulator of its series of Natural Gas Vehicle regulators. High Pressure and is designed to expand the gas mainly outside the body of the regulator, beyond the outlet 40. As a result, the regulator is not subject to the extreme cold of the expanding gas. The outer tube 22 directs the low pressure, cold gas from the outlet 40 to the gas inlet 42 of the heater 10.

The heater 10 includes a box 43 with three main sections, a cylindrical part 44, an extension 46 and an end head 48. The cylindrical portion, the extension and the end head 44 are held together by a threaded bolt 50 which is threaded into the extension of the housing 46 and extends through the the cylindrical part of the case 44 and the end head 48. A nut 52 at the end of the heater retains the bolt 50. A pair of bolts 54 ensure the extension of the case to the body of the regulator 36. An O-shaped seal 57 provides a seal between the extension of the housing and the body of the regulator 36. The bolts 55 hold the end head 48 of the cylindrical part 44 with an O seal seal 59 therebetween.

The cooling inlet 56 of the heater is provided in the extension 46. The extension of the box is a rate shape having a radial end wall 62 and forms a hollow chamber 58. The chamber 58 is open at the end of the heater facing the regulator 18. When the heater is mounted to the regulator, the regulator body 36 closes the chamber 58. The inlet of the cooler 56 admits the liquid cooler in the chamber 58, which the cooler makes contact with the regulator body 36 to heat the regulator. The extension of the box has an opening 60 through the radial end wall 62 to allow flow of the cooler from the chamber 58. The opening 60 is positioned opposite from the inlet of the cooler 56 such that the cooler entering the chamber 58 must flow through the regulator body to opening 60.

The cylindrical part 44 has a bottom wall 64 at one end and is open at the opposite end which is sealed against the extension with an O-seal seal 65. A core 66 is placed inside the cylindrical part 44. The core it has a cylindrical or tubular wall 68 with a plurality of inwardly extending fins 70 and outwardly extending fins 72. Bolt 50 extends through the core inside tubular wall 68. A final cover 74, similar to a washer is positioned at the open end of the cylindrical part and rests on the ends of the outer fins 72. The cover 74 extends radially between the tubular wall 68 of the core and the inner surface of the cylindrical part of the box 44. The tubular wall 68 of the core 66 divides the inside of the cylindrical part of the box 44 into the separate conduits of the cooler and the gas. The gas conduit is radially out of the tubular wall 68 while the cooler conduit 78 is inside the tubular wall 68. The cover 74 is spaced from the end wall 62 of the extension to provide a separation 79 for the flow of the cooler from the opening 60 to the center of the core where the cooler flows through the tubular wall, on the surface of the inner fins 70. The cooler heats the tubular wall 68 and the outer fins 72.

The cooler flows into the well 80 formed in the end head 48. From the well 80, the cooler flows through the sump 82 to a transverse hole 84 leading to a cooler outlet 86. The sump 82 forms a rib 83 for a thermostat 90. The thermostat 90 has a socket 92 which is threaded into the bottom wall 64 of the cylindrical part of the case 44. The thermostat 90 includes a plunger 91 which meshes a seat 85 to close the sump 82, stopping the flow of the chiller through the heater. The plunger 91 is pressed away from the seat 85 by a spring 93 which meshes the projection 83 and the edge 95 of the plunger. A rod 97 is connected to the plunger 91 and extends into a reservoir of wax 94. The reservoir of wax is placed in the gas conduit adjacent to the gas outlet 96. If the temperature of the fuel gas rises very high, the wax it melts and increases in volume, which causes the rod and plunger to move against the spring until the plunger engages the seat 85 to stop the flow of the cooler. When the gas temperature then falls, the wax solidifies and contracts, allowing the plunger to move away from the seat by the force of the spring and allows the flow of the cooler to be summarized. The wax reservoir of the thermostat 94 is positioned in the cylindrical part of the box 44 in the gas conduit adjacent to the gas outlet of the heater 96 so that the thermostat responds to the temperature of the gas, not to the temperature of the cooler, in regulate the flow of the cooler through the heater. As a result, the gas is maintained at a constant temperature or near a constant temperature while the temperature of the regulator body may vary somewhat depending on the flow of the cooler through the extension of the box 46 necessary to maintain the gas temperature desired.

The core 66 is shown in greater detail with reference to Figs. 7 to 10. The core includes an extrusion that forms the tubular wall 68 and the inwardly directed flaps 70. The exterior of the wall 68 is formed with a plurality of grooves in the groove. circumferentially spaced T-shape 98. The slots 98 receive the individual fins 72. The fins have an elongated edge 104 that is T-shaped in cross section as shown in Figure 10. * - * - - * - • * ^ - * - > 'fins are truncated at one end by a cut-off part 102. The fins are mounted on the wall 68 by the sliding T-shaped edge 104 along the edges 98. The fins 70 are arranged with a cut part 102 at the ends alternating the core 66, which forms a serpentine path for the gas flow on the surface of the fins 70 as shown by the arrows 110 in Figure 7.

With specific reference to Figure 8, the core wall 68 is shown with a larger space 106 adjacent the slots T and another larger space 108 between the adjacent slots T. Two closely spaced T-slots 98 separate the spaces 106 and 108 The space 106 is provided adjacent to the gas flow outlet 96 in the cylindrical part of the case 44 while the space 108 is positioned adjacent to the gas inlet 42. The two slots 98 between the spaces 106 and 108 are provided for two full-length fins 112 that are like fins 72 without the cut portions 102. The fins 112 provide an air space therebetween which creates an insulating layer between the gas inlet 42 and the gas outlet 96 so that the inlet of gas does not cool the gas outlet.

The external connection between the regulator outlet and the gas inlet of the heater via the tube 22 allows a sufficient length of fuel line to be easily used without the heater 10 if the application provides a ? 12 sufficient line length between the regulator and the engine measuring valve to heat the fuel to the environment. The heater is not mounted to the regulator, and the fuel line 24 to the engine is directly connected to the outlet 5 of the regulator 40.

While it is preferred to mount the heater to the regulator such that the regulator is also heated by the cooler, the heater can also be used as a single heater. In this case, there will not be an open chamber 58 for the cooler to heat the regulator. Preferably, the cooler can flow through an inlet in the core area of the heater for flow through the interior of the tubular wall 68 to heat the core 66. The heater still has the advantage of regulating the coolant flow as a function of the gas temperature, not the cooler temperature.

The invention should not be limited to the embodiment described above, but should be limited only by the claims that follow. . »- -

Claims (20)

1. A fuel gas heater mounted to a fuel gas regulator, the regulator has a regulating body with a high pressure gas inlet and a low pressure gas outlet, the heater comprises: a box for the heater attached to the regulator body, the heater box has a gas inlet in communication with the outlet of the regulator and a gas outlet, the heater box also has a cooler inlet and a cooler outlet and a cooler conduit therebetween which is partially defined by the regulator body where the cooler in the cooler conduit engages the regulator cleat; a core within the heater housing defines a gas conduit and separates the gas conduit from the cooler conduit therein; Y a flow control member of the gas temperature cooler in the gas conduit for opening and closing the cooler conduit to allow or prevent flow of the cooler through the cooler conduit as a function of gas temperature.

2. The heater, as claimed in clause 1, characterized in that the flow control member of the cooler is partially positioned in the gas conduit adjacent to the gas outlet to respond to the temperature of the gas.

3. The heater, as claimed in clause 1, characterized in that it comprises a gas flow tube from the outlet of the gas regulator to the gas inlet of the heater housing to the body of the regulator and to the heater housing.

4. The heater, as claimed in clause 1, characterized in that the heater housing has a cylindrical part with the core positioned inside radially separating the cooler and gas conduits.

5. The heater, as claimed in clause 4, characterized in that the box has an extension at one end of the cylindrical part that engages the regulator body and has the cooler inlet therein with the cooler conduit at the extension which is defined in part by the regulator body.

6. The heater, as claimed in clause 5, characterized in that the cooler flows laterally through the regulator body within the extension from the cooler inlet after which the cooler flows axially into the cylindrical part of the cooler housing. Heater.

7. The heater, as claimed in clause 4, characterized in that the core has a cylindrical wall separated inwardly from the cylindrical part of the heater box that radially separates the conduits of the cooler and the gas.

8. The heater, as claimed in clause 7, characterized in that it comprises fins extending radially outward from the cylindrical core wall to the cylindrical part of the casing and defining the gas conduit, the fins are axially truncated at alternating axial ends to define a serpentine gas conduit around the fins with the cooler conduit inside the cylindrical core wall.

9. The heater, as claimed in clause 8, characterized in that the gas inlet and outlet of the heater housing are circumferentially spaced from one another in the cylindrical part of the heater housing.

10. The heater, as claimed in clause 9, characterized in that two fins of the core are placed between the gas inlet and the gas outlet of the heater box.

11. The heater, as claimed in clause 1, characterized in that the inlet of the cooler is adjacent to the regulator body and the outlet of the cooler is adjacent to the gas outlet of the heater.

12. The heater, as claimed in clause 1, characterized in that the flow control member of the cooler includes a reservoir of wax placed in the gas conduit and therefore responds to the temperature of the gas.

13. A fuel gas heater comprising: a box for the heater that has a gas inlet in communication with a gas source and the box has a gas outlet, the heater box also has a cooler inlet and a cooler outlet and a duct between them which it is partially defined by the body of the regulator where the regulator box engages in the cooler duct; a core inside the heater housing defines a gas conduit and separates the gas conduit from the cooler conduit therein; Y a flow control member of the cooler that responds to the gas temperature in the gas conduit to open and close the cooler conduit to allow or prevent coolant flow through the cooler conduit as a function of the gas temperature .

14. The heater, as claimed in clause 13, characterized in that the coolant flow control member is partially positioned in the gas conduit adjacent to the gas outlet to respond to the temperature of the gas.

15. The heater, as claimed in clause 13, characterized in that the heater housing has a cylindrical part with the core placed therein radially separating the conduits of the cooler and the gas.

16. The heater, as claimed in clause 15, characterized in that the core has a wall separated inwardly from the cylindrical part of the heater of the heater housing that radially separates the conduits from the cooler and from the gas.

17. The heater as claimed in clause 16, characterized in that it comprises fins extending radially outward from the cylindrical core wall to the cylindrical part of the casing and defining the gas conduit, the fins are axially truncated in alternating axial ends to define a serpentine gas conduit around the fins with the cooler conduit inside the cylindrical core wall.

18. The heater, as claimed in clause 17, characterized in that the gas outlet and the inlet of the heater housing are separated circumferentially from one another in the cylindrical part of the heater housing.

19. The heater, as claimed in clause 18, characterized in that two fins of the core are placed between the gas outlet and the gas inlet of the heater housing.

20. The heater, as claimed in clause 13, characterized in that the flow control member of the cooler includes a reservoir of wax placed in the gas conduit and therefore responds to the temperature of the gas.