JP7776290B2 - Tanker truck - Google Patents

Description

The present invention relates to a tank truck, and in particular to a tank truck that can efficiently discharge liquefied gas from a tank.

A technology is known in which liquefied gas in a tank is sent to a pressurized evaporator, and the pressure of the gas generated by evaporating the liquefied gas is used to expel the liquefied gas from the tank to the outside. For example, Patent Document 1 describes a technology in which pressurized evaporators are installed on both sides of the vehicle width.

JP 2013-193690 A (for example, paragraph 0028, Figures 1 and 2)

When pressurized evaporators are provided on both sides of the vehicle width as in the conventional technology described above, if the vehicle body tilts widthwise relative to the horizontal, one of the pressurized evaporators will be raised. In this state, when liquefied gas in the tank is sent to the pressurized evaporator, liquefied gas is more easily sent to the other pressurized evaporator, but not enough liquefied gas can be sent to the raised pressurized evaporator. As a result, the amount of vaporized gas returned from the pressurized evaporator to the tank is insufficient, resulting in the problem of the liquefied gas in the tank not being efficiently discharged.

The present invention was made to solve the above-mentioned problems, and aims to provide a tank truck that can efficiently discharge liquefied gas from a tank.

In order to achieve this object, the tank truck of the present invention comprises a tank, a chassis frame supporting the tank, a pair of pressurized evaporators arranged on both sides of the chassis frame in the vehicle width direction, vaporizing the liquefied gas in the tank and returning it to the tank, and pressurizing the inside of the tank, and a delivery pipe connecting the tank to the inlets of the pair of pressurized evaporators, the inlets being arranged to face the center of the vehicle width , and delivering the liquefied gas in the tank to each of the pair of pressurized evaporators, wherein a portion of the delivery pipe extending in the vehicle width direction has a gradient that slopes downward from the upstream side to the downstream side , and the delivery pipe comprises a first pipe extending downward from the rear of the tank and a second pipe branching out in the vehicle width direction from the lower end of the first pipe. and a second pipe that branches off and is connected to the inlets of a pair of the pressurized evaporators, wherein the connection position of the first pipe and the second pipe and the connection position of the second pipe and the inlets of the pressurized evaporators are set at positions separated in the fore-and-aft direction, and the second pipe is composed of a pair of first inclined portions extending from the lower end of the first pipe on both sides in the vehicle width direction, a pair of second inclined portions extending in the fore-and-aft direction from the outer ends of the pair of first inclined portions on the vehicle width direction, and a pair of third inclined portions extending outward in the vehicle width direction from the outer ends of the pair of second inclined portions and connected to the inlets of the pressurized evaporators, and has a gradient that slopes downward from the upstream side to the downstream side, and the connection portions of the first inclined portions, the second inclined portions, and the third inclined portions are curved .

According to the tank truck described in claim 1, the portion of the delivery pipe extending in the vehicle width direction has a downward slope from the upstream side to the downstream side. Therefore, even when the vehicle body is tilted in the vehicle width direction relative to the horizontal direction and one of the pressurized evaporators is in a raised tilted state, liquefied gas is easily delivered to the raised pressurized evaporator. Therefore, a sufficient amount of vaporized gas can be returned from each of the pair of pressurized evaporators to the tank, which has the effect of efficiently discharging the liquefied gas from the tank.

In addition, according to the tank truck described in claim 1, the delivery pipe comprises a first pipe extending downward from the rear of the tank and a second pipe branching from the lower end of the first pipe in the vehicle width direction and connected to each of a pair of pressurized evaporators, so that liquefied gas can be delivered to each of a pair of pressurized evaporators through a single first pipe.

Since the connection position of the first pipe and the second pipe and the connection position of the second pipe and the inlet of the pressurized evaporator are set at positions separated in the front-rear direction, a portion of the second pipe is formed to extend in the front-rear direction. In contrast, in claim 1, since the second pipe has a downward slope from the upstream side to the downstream side, liquefied gas can be easily delivered to each of the pair of pressurized evaporators regardless of whether the vehicle body is tilted in the vehicle width direction or the front-rear direction. This has the effect of more efficiently discharging the liquefied gas from the tank.

According to the tank truck of claim 1, the second pipe is composed of the first inclined portion, the second inclined portion, and the third inclined portion, and the connecting portion of each inclined portion is curved, so that when a load that expands or contracts the second pipe in the front-rear direction acts on the second pipe, the second pipe can be deformed to absorb the load, thereby having the effect of suppressing damage to the second pipe.

According to the tank truck of claim 2, in addition to the effects of the tank truck of claim 1, since the downward inclination of the delivery pipe is constant, the ease of flow of the liquefied gas can be made uniform over the entire length of the inclined portion of the delivery pipe. This makes it easier to deliver the liquefied gas to each of the pair of pressurized evaporators, and has the effect of more efficiently discharging the liquefied gas from the tank.

The tank truck of claim 3 achieves the following effect in addition to the effect of the tank truck of claim 1 or 2. The delivery pipe that delivers the liquefied gas in the tank to the pressurized evaporator and the return pipe that returns the gas vaporized by the pressurized evaporator to the tank connect the tank and the pressurized evaporator. Therefore, for example, if the pressurized evaporator is configured to be fixed to the chassis frame, the routes of the delivery pipe and return pipe must be set to match the shape of the chassis frame, etc.

In contrast, in claim 3 , a subframe is fixed to a tank unit that integrates the tank, delivery pipe, pressurized evaporator, and return pipe, and the tank unit is mounted to a chassis frame via the subframe, so the routes of the delivery pipe and return pipe can be set without depending on the shape of the chassis frame. Furthermore, by positioning the connection position of the first pipe and the second pipe that pass between a pair of chassis frames below the chassis frames, the route of the second pipe can be set without depending on the shape of the chassis frame. Therefore, there is an effect that the above tank unit can be mounted to chassis frames of various shapes.

1 is a side view of a tank truck according to an embodiment of the present invention. FIG. FIG. 3 is a partially enlarged cross-sectional view of the tank truck taken along line III-III in FIG. 2. FIG. 4 is a partially enlarged cross-sectional view of the tank truck showing an enlarged portion IV of FIG. 3. FIG. 4 is a partially enlarged cross-sectional view of the tank truck taken along line VV in FIG. 3. FIG. 6 is a partially enlarged cross-sectional view of the tank truck taken along line VI-VI in FIG. 5. FIG. 7 is a partially enlarged bottom view of the tank truck as viewed in the direction of arrow VII in FIG. 6 . FIG. 10 is a partially enlarged cross-sectional view of a tank truck according to a modified example.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. First, the overall configuration of a tank truck 1 will be described with reference to Figure 1. Figure 1 is a side view of a tank truck 1 in one embodiment of the present invention.

As shown in Figure 1, the tank truck 1 is equipped with multiple wheels 2 and is configured as a vehicle for transporting liquefied gas (e.g., LNG). The multiple wheels 2 support a chassis frame 3 that forms the framework of the vehicle body.

The chassis frame 3 is a frame that extends in the fore-and-aft direction of the vehicle body (left-and-right direction in Figure 1), and a cab 30 that serves as a driver's seat is located at the front end of the chassis frame 3. A tank 5 is supported (mounted) via a subframe 4 on the chassis frame 3, which is located rearward of the cab 30. Before the tank 5 is supported on the chassis frame 3 (before mounting), the subframe 4 is fixed to the tank 5 by welding or the like, and the tank 5 is mounted on the chassis frame 3 by fixing the subframe 4 to the chassis frame 3 with fixing devices (not shown) or by welding.

Tank 5 is a cylindrical tank for carrying liquefied gas. A delivery pipe 6 is connected to the rear of tank 5, and a pressurized evaporator 7 is connected to tank 5 via delivery pipe 6. Pressurized evaporator 7 is a device that vaporizes the liquefied gas delivered from tank 5 through delivery pipe 6 to produce gas, and returns the gas to tank 5. The detailed configuration of delivery pipe 6 will be described later.

Next, the mounting structure of the pressurized evaporator 7 will be described with reference to Figures 2 to 4. Figure 2 is a partially enlarged perspective view of the tank truck 1, Figure 3 is a partially enlarged cross-sectional view of the tank truck 1 taken along line III-III in Figure 2, and Figure 4 is a partially enlarged cross-sectional view of the tank truck 1 taken along line IV in Figure 3.

As shown in Figures 2 and 3, side frames 40 are connected to the sides of the subframe 4. The subframe 4 extends rearward beyond the tank 5, and in the following description, the portion of the subframe 4 that is connected to the tank 5 will be referred to as the connecting portion 4a, and the portion that protrudes rearward beyond the tank 5 from the connecting portion 4a will be referred to as the protruding portion 4b (see Figure 3). Of the multiple side frames 40, the one connected to the connecting portion 4a will be referred to as the side frame 40a, and the one connected to the protruding portion 4b will be referred to as the side frame 40b.

The side frames 40a, 40b are C-shaped (channel steel in this embodiment) frames that protrude outward in the left-right direction (vehicle width direction) beyond the tank 5. The pressurized evaporator 7 is fixed to the subframe 4 via these side frames 40a, 40b. That is, the pressurized evaporator 7 is connected to the chassis frame 3 via the side frames 40a, 40b and the subframe 4, but is not directly connected to the chassis frame 3. This prevents the load caused by the deformation from acting directly on the pressurized evaporator 7 from the chassis frame 3, even if the chassis frame 3 is deformed, for example, by vibrations while the tank truck 1 is traveling. Furthermore, since the subframe 4 is fixed to the cylindrical tank 5, it has a relatively high rigidity and is resistant to deformation. This prevents the load caused by the deformation of the chassis frame 3 from acting on the pressurized evaporator 7 via the subframe 4.

Multiple side frames 40a, 40b (three in this embodiment) are provided at predetermined intervals in the front-to-rear direction, and the pressurized evaporator 7 is supported (fixed) on the undersides of these multiple side frames 40a, 40b. As a result, even if the subframe 4 is deformed due to the above-mentioned deformation of the chassis frame 3, the load caused by that deformation can be prevented from acting on the pressurized evaporator 7 via the side frames 40a, 40b. In other words, the load acting on the pressurized evaporator 7 when the chassis frame 3 is deformed can be reduced compared to when the pressurized evaporator 7 is fixed directly to the subframe 4.

The connecting portion 4a of the subframe 4, which connects to the tank 5, is constructed with relatively high rigidity compared to the protruding portion 4b, which protrudes rearward beyond the tank 5. Because the side frame 40a is connected to the highly rigid connecting portion 4a, the pressurized evaporator 7 can be fixed using the connecting portion 4a of the subframe 4, which is relatively resistant to deformation. This prevents the load acting on the pressurized evaporator 7 via the subframe 4 and side frame 40a when the chassis frame 3 deforms. In this way, by reducing the load acting on the pressurized evaporator 7 when the chassis frame 3 deforms, damage to the pressurized evaporator 7 can be reduced.

A connecting frame 41 for fixing the pressurized evaporator 7 is connected to the underside of the side frames 40a, 40b. The connecting frame 41 is a frame with a C-shaped cross section (in this embodiment, a channel steel shape) that extends left and right, and the frame body 70 of the pressurized evaporator 7 is fixed to the underside of the connecting frame 41. The frame body 70 is a rectangular frame that forms the outer shell of the pressurized evaporator 7, and the interior of the frame body 70 houses the piping of the inlet header 71, serpentine pipe 72, and outlet header 73, which will be described below.

The inlet header 71 is a pipe that extends in the left-right direction at the front end of the frame 70, and the aforementioned delivery pipe 6 is connected to the inner left-right end (towards the center of the vehicle width) of the inlet header 71. Therefore, the liquefied gas in the tank 5 is introduced into the pressurized evaporator 7 via this inlet header 71. The connection port at the inner left-right end of the inlet header 71 to which the delivery pipe 6 is connected is the "inlet" of the pressurized evaporator 7.

One end of multiple serpentine pipes 72 arranged side by side is connected to the inlet header 71. The serpentine pipes 72 are pipes for evaporating and vaporizing liquefied gas, and are composed of straight pipes 72a extending in the front-to-rear direction and U-shaped pipes 72b (see Figure 3) that connect the ends of the straight pipes 72a.

A single serpentine pipe 72 is formed by connecting the front and rear ends of multiple vertically arranged straight pipes 72a with U-shaped pipes 71b. In other words, the serpentine pipe 72 is arranged so that it snakes multiple times from the lower end (one end) of the pressurized evaporator 7 to the upper end (the other end).

The other end of each of the multiple serpentine pipes 72 is connected to an outlet header 73. The outlet header 73 is a pipe extending in the left-right direction, and one end of the return pipe 8 is connected to the left-right center of the top surface of the outlet header 73. Although not shown in the figure, the other end of the return pipe 8 is connected to the tank 5 through the equipment room 9, which will be described later.

In the pressurized evaporator 7 configured in this manner, the liquefied gas introduced from the inlet header 71 is vaporized by heat exchange with the outside air as it flows through the serpentine pipe 72, and the vaporized gas is returned to the tank 5 via the outlet header 73 and return pipe 8. As the liquefied gas flows into the serpentine pipe 72 and stops flowing into it, the serpentine pipe 72 may expand and contract in the forward and backward directions. To allow for this expansion and contraction, the straight pipe 72a of the serpentine pipe 72 is supported in a slidable manner by a support member 74. This support structure is described below.

The support member 74 is a plate-like body extending in the left-right direction, and both left and right ends of the support member 74 are fixed to the frame body 70. The support member 74 has a plurality of through holes (not shown) formed in a row in the left-right direction, and the straight tube 72a of the serpentine tube 72 is slidably inserted into each of the plurality of through holes. This allows the serpentine tube 72 (straight tube 72a) to be supported by the support member 74 while allowing expansion and contraction of the serpentine tube 72. Multiple support members 74 (six in this embodiment) are arranged in a row in the vertical direction, and these multiple support members 74 are connected to each other by connecting rods 75 (see Figure 4).

As shown in Figure 4, the upper end portion of the connecting rod 75 is inserted into the through-hole 41a of the connecting frame 41 and fixed to the connecting frame 41, and the support member 74 is fixed to the underside of the side frames 40a, 40b via the connecting rod 75 and the connecting frame 41. This allows the support member 74 to be supported not only by the frame body 70, which supports both the left and right ends of the support member 74, but also by the side frames 40a, 40b, thereby preventing damage to the pressurized evaporator 7.

In other words, the load from the serpentine pipe 72 as described above acts on the connection between the support member 74 and the frame 70 via the support member 74 due to vibrations during driving, etc. Therefore, for example, if only the top surface of the frame 70 of the pressurized evaporator 7 is fixed to the side frames 40a, 40b (connecting frame 41), the load described above tends to concentrate on one part of the frame 70, making the pressurized evaporator 7 (frame 70) more susceptible to damage.

In contrast, in this embodiment, multiple support members 74 lined up vertically are integrated by connecting rods 75, and the upper ends (connecting rods 75) of the integrated support members 74 are supported by the side frames 40a, 40b via the connecting frame 41. This reduces the load acting on the frame 70 compared to when only the upper surface of the frame 70 is fixed to the side frames 40a, 40b (connecting frame 41). Furthermore, because the connecting rods 75 connecting the multiple support members 74 are fixed to the side frames 40a, 40b via the connecting frame 41, the fixed portions of the connecting rods 75 (upper ends of the support members 74) can be reinforced by the side frames 40a, 40b and the connecting frame 41. This reduces damage to the pressurized evaporator 7 (frame 70).

In this way, the support members 74 are supported by being suspended from the side frames 40a and 40b. As shown in FIG. 3, of the multiple support members 74 lined up front and behind, the support member 74 suspended from the side frame 40a supports both ends of the serpentine pipe 72 (i.e., the connection portions with the inlet header 71 and outlet header 73). The side frame 40a is connected to the connecting portion 4a, which has relatively high rigidity among the subframes 4. Therefore, by connecting the serpentine pipe 72 to the inlet header 71 and outlet header 73 near this side frame 40a, it is possible to prevent loads due to deformation of the chassis frame 3 from acting on these connection portions (areas where leakage is a concern). This prevents leakage from occurring at the connection portions between the serpentine pipe 72 and the inlet header 71 and outlet header 73.

However, because the side frame 40b is connected to the protruding portion 4b (which is not connected to the tank 5) and has lower rigidity than the connecting portion 4a, the support member 74 (serpentine pipe 72) supported by this side frame 40b may be subjected to a load due to deformation such as twisting of the chassis frame 3. In contrast, in this embodiment, as described above, the serpentine pipe 72 (straight pipe 72a) is supported in a slidable state on the support member 74. Therefore, even if a load due to deformation of the chassis frame acts on the support member 74 (serpentine pipe 72) via the side frame 40b, damage to the pressurized evaporator 7 caused by that load can be suppressed.

In addition, in this embodiment, in order to reduce the effects of deformation of the chassis frame 3, the protrusion 4b is reinforced by a reinforcing frame 42 (see Figure 5) or the like. This configuration will be described with reference to Figures 5 and 6.

Figure 5 is a partially enlarged cross-sectional view of the tank truck 1 taken along line V-V in Figure 3, and Figure 6 is a partially enlarged cross-sectional view of the tank truck 1 taken along line VI-VI in Figure 5. Note that Figures 5 and 6 only show the essential parts of the tank truck 1, and some components (for example, the structure of the pressurized evaporator 7) are not shown.

As shown in Figures 5 and 6, a pair of sub-frames 4 are provided at a predetermined distance in the left-right direction, and a pressurized evaporator 7 is fixed to each of the pair of sub-frames 4. In the following explanation, of the pair of pressurized evaporators 7, the one fixed to the left sub-frame 4 will be referred to as pressurized evaporator 7a, and the one fixed to the right sub-frame 4 will be referred to as pressurized evaporator 7b.

The pair of pressurized evaporators 7a, 7b are configured symmetrically. Therefore, for example, each component connected to the pressurized evaporator 7 described above (e.g., side frames 40a, 40b and return pipe 8) is provided on each of the pair of pressurized evaporators 7a, 7b.

The protruding portions 4b of the pair of subframes 4 are connected by a reinforcing frame 42. The reinforcing frame 42 is a frame with a C-shaped cross section (in this embodiment, a channel steel shape) that extends left and right, and is positioned so that it overlaps with each of the pair of left and right side frames 40b when viewed left and right (when viewed left and right in Figure 5).

In other words, the reinforcing frame 42 is positioned between the side frame 40b to which the left pressurized evaporator 7a is fixed and the side frame 40b to which the right pressurized evaporator 7b is fixed, thereby reinforcing the connection between the protrusion 4b and the side frame 40b, which has relatively low rigidity. This prevents deformation such as twisting of the subframe 4 (protrusion 4b) at this connection, thereby preventing the load caused by deformation of the chassis frame 3 from acting on the pressurized evaporator 7 via the subframe 4 and side frame 40b.

Furthermore, if a pair of left and right side frames 40b are considered to be one set, a reinforcing frame 42 is disposed between each of the multiple sets (two sets in this embodiment) of side frames 40b lined up in the front-to-rear direction (see Figure 7). That is, multiple reinforcing frames 42 (two in this embodiment) are arranged in the front-to-rear direction, thereby effectively reinforcing the pair of protrusions 4b. Note that, because the connecting portions 4a of the subframe 4 have relatively high rigidity, no reinforcing frame 42 is provided between the connecting portions 4a (between a pair of side frames 40a) (see Figure 7).

Aft of the tank 5 is an equipment room 9 that covers the rear end of the tank 5, and this equipment room 9 also reinforces the protruding portion 4b of the subframe 4. Specifically, the equipment room 9 is box-shaped with an opening 90 (see Figure 5) on the rear side, and inside the equipment room 9 are installed operating devices and meters (neither of which is shown) that are operated during liquefied gas loading and unloading operations. The left-right dimension of the floor plate 91 of the equipment room 9 is set larger than the distance between the pair of subframes 4, and the left and right ends of the floor plate 91 protrude laterally beyond the pair of subframes 4.

The floor panel 91 of the equipment room 9 extends rearward from the rear surface of the tank 5 (see Figure 6), and the rear end portion of the floor panel 91 extends to the rearmost side frame 40b among the multiple side frames 40b.

The floor panel 91 of the equipment compartment 9 is fixed to the upper surface of the protruding portion 4b of the subframe 4 by welding or other means, allowing the protruding portion 4b, which has relatively low rigidity, to be reinforced by the floor panel 91 of the equipment compartment 9. This prevents deformation such as twisting of the subframe 4 (protruding portion 4b) at the connection between the protruding portion 4b and the side frame 40b, thereby preventing the load generated when the chassis frame 3 deforms from acting on the pressurized evaporator 7 via the subframe 4 and side frame 40b. Furthermore, in addition to its function of storing equipment, the equipment compartment 9 can also have the function of reinforcing the protruding portion 4b.

The floor panel 91 of the equipment room 9 is also fixed by welding or other means to multiple reinforcing frames 42 (see Figure 6) arranged in the front and rear. This also effectively reinforces the protruding portion 4b, which has relatively low rigidity.

As mentioned above, the tank 5 and the pressurized evaporator 7 are connected by a delivery pipe 6 that delivers the liquefied gas in the tank 5 to the pressurized evaporator 7 and a return pipe 8 (see Figure 3) that returns the gas vaporized by the pressurized evaporator 7 to the tank 5. Therefore, for example, if the pressurized evaporator 7 is fixed to the chassis frame 3, the routes of the delivery pipe 6 and return pipe 8 must be set to match the shape of the chassis frame 3.

In other words, the distance between the left and right opposing chassis frames 3 and the left and right dimensions (width) of the chassis frame 3 itself may vary depending on the type of vehicle on which the tank truck 1 is based. Therefore, in a configuration in which the pressurized evaporator 7 is fixed to the chassis frame 3 (vehicle body side), the relative position between the tank 5 and the pressurized evaporator 7 changes depending on the type of vehicle (shape of the chassis frame 3), and so the routes of the delivery pipe 6 and return pipe 8 must be changed depending on the type of vehicle. Furthermore, it becomes necessary to modify the chassis frame 3 in order to secure the pressurized evaporator 7.

In contrast, in this embodiment, the subframe 4, tank 5, delivery pipe 6, pressurized evaporator 7, and return pipe 8 are integrated into a tank unit, and the tank unit's subframe 4 is fixed to the chassis frame 3, thereby mounting the tank unit to the chassis frame 3. In other words, because the pressurized evaporator 7 is fixed not to the vehicle body but to the tank unit mounted on the vehicle body, the routes of the delivery pipe 6 and return pipe 8 connecting the tank 5 and pressurized evaporator 7 can be set without depending on the shape of the chassis frame 3. Furthermore, there is no need to process the chassis frame 3 to mount the pressurized evaporator 7. Therefore, the tank unit can be mounted to chassis frames 3 of various shapes (various vehicle models).

Next, the detailed configuration of the delivery pipe 6 will be described with reference to Figures 5 to 7. Figure 7 is a partially enlarged bottom view of the tank truck 1 as viewed in the direction of arrow VII in Figure 6.

As shown in Figures 5 and 6, the delivery pipe 6 includes a first pipe 60 that is connected to the rear surface of the tank 5. Note that in Figure 6, the joint at the connection between the tank 5 and the first pipe 60 is hatched to omit the internal view.

The first piping 60 is composed of a horizontal section 60a extending rearward from the rear surface of the tank 5, and a hanging section 60b hanging downward from the rear end of the horizontal section 60a. Note that the horizontal section 60a extends horizontally when the tank truck 1 is stopped on a level road surface (hereinafter referred to as the "stopped state of the tank truck 1"), but it may also be configured so that the rear end (downstream side) of the horizontal section 60a is inclined downward.

A pair of second pipes 62 branching to the left and right are connected to the lower end of the hanging portion 60b via a T-shaped joint 61. The pair of second pipes 62 on the left and right are symmetrical.

The second piping 62 slopes downward from the joint 61 (upstream side) to the inlet header 71 (downstream side) of the pressurized evaporators 7a, 7b. More specifically, when viewed from the front to rear, the second piping 62 is composed of a first inclined portion 62a extending outward in the left-right direction from the joint 61, a second inclined portion 62b extending forward from the outer left-right end of the first inclined portion 62a, and a third inclined portion 62c extending outward in the left-right direction from the front end of the second inclined portion 62b. Note that in the following description, when the first to third inclined portions 62a to 62c are referred to collectively, they will be referred to as "each inclined portion."

When the tank truck 1 is stopped, each inclined portion has a downward slope (a 9° slope in this embodiment) from the upstream side to the downstream side relative to the horizontal. That is, because the first inclined portion 62a and the third inclined portion 62c extending in the left-right direction are each inclined downward, even when the vehicle body is tilted left-right relative to the horizontal, the first inclined portion 62a and the third inclined portion 62c can maintain their downward slope relative to the horizontal. Therefore, even when the tank truck 1 is tilted relative to the horizontal direction and one of the pair of pressurized evaporators 7a, 7b is raised, liquefied gas can be easily delivered to the raised pressurized evaporator 7a, 7b. Therefore, a sufficient amount of vaporized gas can be returned from each of the pair of pressurized evaporators 7a, 7b to the tank 5, allowing the liquefied gas in the tank 5 to be efficiently discharged.

In addition to the first inclined portion 62a and the third inclined portion 62c, the second inclined portion 62b extending in the longitudinal direction is also inclined downward. In other words, the entire second piping 62 is inclined downward. This makes it easier to deliver liquefied gas to each of the pair of pressurized evaporators 7a, 7b regardless of whether the vehicle body is inclined left-right or front-to-rear. This allows the liquefied gas in the tank 5 to be discharged more efficiently.

As mentioned above, the shape of the chassis frame 3 may differ depending on the vehicle model. However, because the connection position between the hanging portion 60b of the first pipe 60 and the first inclined portion 62a of the second pipe 62 is located below the chassis frame 3, the path of the second pipe 62 can be set regardless of the shape of the chassis frame 3. Therefore, the tank unit, which integrates the subframe 4, tank 5, delivery pipe 6, pressurized evaporator 7, and return pipe 8, can be mounted on chassis frames 3 of various shapes (various vehicle models).

The gradient of the road surface on which the tank truck 1 performs loading and unloading operations is generally 1 to 2 degrees. Therefore, the gradient of each inclined section is preferably set to 3 degrees or more, and in this embodiment is set to 9 degrees. This allows each inclined section to maintain a downward tilt relative to the horizontal when the tank truck 1 is stopped on a typical road surface, ensuring that liquefied gas can be reliably delivered to each of the pair of pressurized evaporators 7a, 7b.

In addition, because the gradient of the downward slope of the second piping 62 is set at a constant angle throughout the entire second piping 62 (each inclined section), the ease of flow of liquefied gas can be made uniform throughout the entire length of the second piping 62. This makes it easier for liquefied gas to be delivered to each of the pair of pressurized evaporators 7a, 7b. The outer left-right ends of the third inclined section 62c of the second piping 62 are connected to the inlet header 71 via fitting 63, and the "entire" second piping 62 refers to the piping section from the edge of the opening of fitting 61 to the edge of the opening of fitting 63.

As shown in Figure 7, the connection portions of the first inclined portion 62a, the second inclined portion 62b, and the third inclined portion 62c of the second pipe 62 are gently curved. In other words, the second pipe 62 is formed in a roughly S-shape that connects the fittings 61, 63, which are positioned apart in the front-to-rear direction.

As a result, even if the second pipe 62 expands or contracts as liquefied gas flows into or stops flowing into the second pipe 62, the curved portion of the second pipe 62 can be deformed to accommodate the expansion or contraction. Furthermore, even if a load that causes the same expansion or contraction as described above acts on the second pipe 62 due to vibrations during driving, etc., the second pipe 62 can be deformed to absorb the load. Therefore, damage to the second pipe 62 can be suppressed.

The present invention has been described above based on the above embodiment, but the present invention is in no way limited to the above form, and it can be easily imagined that various modifications and improvements are possible within the scope of the present invention.

In the above embodiment, a pair of pressurized evaporators 7a, 7b are fixed to the subframe 4 via the side frames 40a, 40b. However, for example, the pressurized evaporator 7 may be fixed directly to the subframe 4. Alternatively, the pressurized evaporator 7 may be fixed to only one of the connecting portion 4a or the protruding portion 4b of the subframe 4 via the side frames 40a, 40b. Alternatively, one or three or more pressurized evaporators 7 may be fixed to the subframe 4.

A modified example in which one pressurized evaporator 7 is fixed to the subframe 4 will now be described with reference to Figure 8. The same parts as in the above embodiment are designated by the same reference numerals, and detailed description will be omitted. Figure 8 is a partially enlarged cross-sectional view of a tank truck 1 in this modified example. Note that Figure 8 is a cross-sectional view taken at a position corresponding to line V-V in Figure 3. To simplify the drawing, Figure 8 omits the illustration of the serpentine pipe 72 (see Figure 2 or 3) connecting the inlet header 71 and outlet header 73.

As shown in Figure 8, in the tank truck 1 of this modified example, one pressurized evaporator 7 is suspended and fixed to a pair of left and right side frames 40a, 40b (see Figure 2 or Figure 3 for side frame 40a) and a reinforcing frame 42. As in the above embodiment, the inlet header 71 extends to both the left and right sides from the downstream end of the third inclined portion 62c of the second piping 62 (via joints 63). The outlet header 73 is connected to the inlet header 71 via a serpentine pipe 72 (not shown) (see Figure 2 or Figure 3).

The outlet header 73 is a pipe that extends left and right above the inlet header 71. A pair of outlet headers 73 are provided on the left and right sides, sandwiching the hanging portion 60b of the first pipe 60, and this pair of outlet headers 73 is connected to the tank 5 via the return pipe 8.

In this modified tank truck 1, the pressurized evaporator 7 is also fixed to the subframe 4 via the side frames 40a, 40b and the reinforcing frame 42. In other words, the pressurized evaporator 7 is connected to the chassis frame 3 via the side frames 40a, 40b, the reinforcing frame 42, and the subframe 4, and is not directly connected to the chassis frame 3. This prevents the load caused by the deformation from acting directly on the pressurized evaporator 7 from the chassis frame 3, even if the chassis frame 3 is deformed, such as twisted, due to vibrations while the tank truck 1 is traveling.

In the above embodiment, a configuration was described in which the protrusion 4b of the subframe 4 is reinforced by the reinforcing frame 42 and the equipment compartment 9, but the reinforcing frame 42 and the equipment compartment 9 may be omitted.

In the above embodiment, the upper end of the support member 74 is fixed to the side frames 40a, 40b via the connecting rod 75 and the connecting frame 41, but the upper end of the support member 74 may be fixed directly (or via the connecting rod 75) to the side frames 40a, 40b. Alternatively, only the left and right ends of the support member 74 may be fixed to the frame body 70.

In the above embodiment, a constant inclined section is provided on the second pipe 62 of the delivery pipe 6. However, the entire delivery pipe 6 may be configured to slope downward when the tank truck 1 is stopped, or a portion (e.g., the second inclined section 62b) or the entire second pipe 62 may extend horizontally. It is also possible to change the gradient of the downward slope in a partial region of the delivery pipe 6 (second pipe 62).

In the above embodiment, we have described a case where the first pipe 60 of the delivery pipe 6 branches off to the left and right and connects to a pair of pressurized evaporators 7a, 7b, i.e., where liquefied gas is delivered to a pair of pressurized evaporators 7a, 7b through a common delivery pipe 6. However, a separate delivery pipe for delivering liquefied gas may also be provided for each of the pressurized evaporators 7a, 7b.

In the above embodiment, the connection position between the first pipe 60 and the second pipe 62 and the connection position between the second pipe 62 and the inlet header 71 of the pressurized evaporator 7 are set at positions separated from each other in the front and rear. However, such connection positions may also be configured so that they are not separated from each other in the front and rear. In this configuration, the second pipe 62 only needs to be configured with an inclined portion corresponding to the first inclined portion 62a described above.

In the above embodiment, the connection position between the first pipe 60 and the second pipe 62 is described as being located below the chassis frame 3, but this connection position may also be at the same height as the chassis frame 3 or above the chassis frame 3.

REFERENCE SIGNS LIST 1 Tank truck 3 Chassis frame 4 Subframe 5 Tank 6 Delivery pipe 60 First piping 62 Second piping 62a First inclined portion 62b Second inclined portion 62c Third inclined portion 7a Pressurized evaporator (first pressurized evaporator)
7b Pressurized evaporator (second pressurized evaporator)
71 Inlet header (inlet of pressurized evaporator)
8 Return pipe

Claims (3)

a pair of pressurized evaporators disposed on both sides of the chassis frame in the vehicle width direction, for vaporizing liquefied gas in the tank and returning it to the tank, and for pressurizing the inside of the tank; and a delivery pipe connecting the inlets of the pair of pressurized evaporators, the inlets being arranged to face the center of the vehicle width, to the tank, and for delivering the liquefied gas in the tank to each of the pair of pressurized evaporators,
a portion of the delivery pipe extending in the vehicle width direction has a gradient that slopes downward from the upstream side to the downstream side ;
the delivery pipe includes a first pipe extending downward from a rear portion of the tank, and a second pipe branching from a lower end of the first pipe in the vehicle width direction and connected to inlets of the pair of pressurized evaporators,
a connection position between the first pipe and the second pipe and a connection position between the second pipe and the inlet of the pressurized evaporator are set at positions separated in the front-rear direction,
the second pipe is composed of a pair of first inclined portions extending from a lower end of the first pipe to both sides in the vehicle width direction, a pair of second inclined portions extending in the front-rear direction from outer ends of the pair of first inclined portions in the vehicle width direction, and a pair of third inclined portions extending outward in the vehicle width direction from the front-rear direction ends of the pair of second inclined portions and connected to an inlet of the pressurized evaporator, and has a gradient that slopes downward from the upstream side to the downstream side,
A tank truck, wherein a connecting portion of the first inclined portion, the second inclined portion, and the third inclined portion is curved . The tank truck according to claim 1, characterized in that the downward slope of the delivery pipe is constant. a pair of subframes fixed to the tank and spaced a predetermined distance apart in the vehicle width direction; a pair of the chassis frames supporting the pair of subframes; and a return pipe connecting outlets of the pair of pressurized evaporators to the tank and returning gas evaporated by the pressurized evaporators into the tank,
the subframe is fixed to a tank unit in which the tank, the delivery pipe, the pressurized evaporator, and the return pipe are integrated, and the tank unit is mounted on the chassis frame via the subframe;
the first pipe extends downward from a rear portion of the tank through a gap between the pair of chassis frames,
3. The tank truck according to claim 1 , wherein the first pipe and the second pipe are connected to each other at a position lower than the chassis frame.