Method and system for propelling liquid through a pipe

Abstract

In a system and method for pumping liquid along a pipe, an impeller is mounted in a the pipe or a housing connected to the pipe. The impeller is driven by a turbine mounted outside the pipe or housing, wherein the turbine is preferably driven by air flow from a compressor. The invention finds use in the emptying the fuel left in the wetlines on a tanker truck, by providing a pipe that extends from the wetlines to the top of the housing tank of the tanker truck, and propelling the fuel using an impeller and turbine arrangement.

Description

FIELD OF THE INVENTION

[0001] The invention relates to the emptying wetlines of tanker trucks, and more generally to the pumping of gasoline and other liquids from one location to another.

BACKGROUND OF THE INVENTION

[0002] The filling and emptying of tanker trucks is achieved through a system of pipes known as wetlines. Tanker trucks typically have one or more housing tanks for housing different grade fuels. In the past gasoline was filled into these housing tanks by pouring the liquid in from the top. However, due to the hazard of having someone climb on top of the truck to supervise the filling, as well as the substantial vapor emissions that took place in such a system, regulations subsequently required the filling from below.

[0003] While this solved some of the problems, it introduced a new hazard. The wetlines which provided the interconnecting pipe sections between the housing tanks and the supply hoses, remained full of liquid once the filling process was complete. At about a gallon per foot of pipe, a tanker truck with 3 sets of wetlines for its three housing tanks could end up carrying 20 to 45 gallons of fuel in its wet lines. As illustrated in FIG. 1, these wetlines are positioned below the tanker truck where they are vulnerable to breach during a motor vehicle accident. Cars colliding with the tanker truck often end up breaking the wetlines and coming to rest under the tanker truck. The fuel in the wetlines typically spills onto the colliding car and ignites, resulting in severe human injuries and even death.

[0004] Various approaches have been proposed to address this problem. One solution is to drain the fluid from the wetlines after filling. The problem with this approach is one of weights and measures. Since the tanker truck is effectively considered as having received the 20-30 gallons in the wetlines, draining this fuel back into the supply tank produces accounting headaches and requires that the fuel that is siphoned off be measured and credit given accordingly. This is both a complex and costly undertaking.

[0005] Another approach is to provide a protective cage around the wetlines. This, however is economically unattractive since it adds significant weight to the tanker truck, which translates into lower fuel carrying capacity.

[0006] Yet another approach is to force a gas into the wetlines, thereby forcing the liquid remaining in the wetlines after the filling process, into the housing tank of the tanker truck. This, however, requires tremendous pressure to be generated in order to force the fuel up against the downward force of the fuel in the housing tank. As a result, powerful pumps or other mechanisms have to be made available, greatly adding to the cost of filling tanker trucks and conveying fuel.

SUMMARY OF THE INVENTION

[0007] The present invention discloses a method and system for emptying the wetlines of tanker trucks, so as to avoid the problems in the prior art solutions.

[0008] The invention involves the use of a separate pipe for conveying fuel from the wetlines to the top of the housing tank of the tanker truck. It further involves the use of a pump that comprises an impeller, for propelling the fuel, and a separate turbine that drives the impeller. Preferably the turbine is driven by compressed air flow.

[0009] The present invention also discloses a system and method generally for propelling liquid in a pipe, making use of an impeller and turbine arrangement.

[0010] According to the invention, there is provided a method of emptying wetlines associated with a housing tank of a tanker truck, comprising, pumping liquid in the wetlines into the housing tank, through a separated pipe extending from the wetlines to a location at or near the top of the housing tank. Typically, separate pipe extends from the wetlines to a location above or near the highest surface of the liquid in the housing tank. Preferably, the separate pipe extends along an inner surface of the housing tank, but it can also extend along an outer surface of the housing tank. Typically, the liquid is pumped using an impeller mounted in the pipe or in an impeller housing connected in fluid flow communication with the pipe. Preferably, the impeller is driven by a turbine.

[0011] Further, according to the invention, there is provided a means for emptying wetlines associated with a holding tank on a tanker truck, comprising, a pipe extending from the wetlines to a location at or near the top of the housing tank, and a pump for pumping the liquid along the pipe into the housing tank. Preferably the pump includes an impeller mounted in the pipe or in an impeller housing connected in fluid flow communication with the pipe, and may, further, include a turbine which drives the impeller. The turbine may be located outside the pipe or the impeller housing, and the turbine may be operated by fluid flow such as the flow of air, water, or oil, for example. Preferably air flow is used, making use of a compressed air source.

[0012] Still further, according to the invention, there is provided a means for propelling liquid through a pipe, comprising an impeller mounted in the pipe or a housing connected in fluid flow communication with the pipe, and a turbine, wherein the turbine is operated by fluid flow, which, preferably, takes the form of air flow from a compressed air source.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a side view of a tanker truck showing a set of wet lines;

[0014] FIG. 2 is a sectional end view of the tanker truck of FIG. 1;

[0015] FIG. 3 is a sectional end view of one embodiment of a wetline emptying system of the invention, and

[0016] FIG. 4 is a sectional side view of one embodiment of an impeller and turbine arrangement of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] A typical tanker truck is shown in FIGS. 1 and 2. Tanker trucks 100 typically include one or more housing tanks 102, each housing tank supporting a particular grade fuel, and having its own set of wetlines 104. The wet lines 104 each include a filling pipe 106 and a draining pipe 108. Fuel is supplied to a filling pipe 106 at a supply station by means of a supply hose 110 connected between a supply tank and a dry connector 112 on the filling pipe 106. The dry connector 112 provides a liquid tight connection for the supply hose 110 and includes a valve that is automatically pushed open by a pin (not shown) mounted in the mating portion 114 on the supply hose 110.

[0018] A second valve 120 is located between the housing tank 102 and the wet lines 104. This valve 120 is a one way valve that is pressure operated and automatically opens as fuel flows into the filling pipe 106.

[0019] Emptying of a housing tank 102 is achieved by draining the fuel, under gravity, from the draining pipe 108. As with the filling pipe 106, the draining pipe 108 is terminated by a dry connector 122.

[0020] Once fuel has been supplied to a housing tank 102 via the filling pipe 106, the supply hose 110 is disconnected, thereby, automatically closing the valve 120 and the valve of the dry connector 112. It will be appreciated that fuel remains trapped in the wet line 104. Since each of the housing tanks 102 has its own set of wetlines 104, and each retains several gallons of fuel, the combined volume of fuel in the wetlines 104 of a typical tanker 100, presents a significant danger.

[0021] In accordance with the present invention, the fuel in the wetlines 104 is pumped out of the wetlines 104 and into the housing tanks 102. As shown in FIG. 3, each of the wetlines 104 is provided with a pipe 130 that extends from the lowest point in the wetline 104 to a location near the top of the housing tank. In a preferred embodiment, the pipe 130 runs along a surface (in this case, the outer surface) of the wetlines 104, passes through the wall 132 of the housing tank 102 at a location 134 adjacent to the valve 120, and runs up the inner surface of the housing tank 102 to a location near the top of the housing tank. Thus fuel is fed from the wetlines 104 into the housing tank 102, thereby emptying the wetline 104. By having the pipe 130 empty out near the top of the housing tank 102, in this embodiment, above the highest surface of the fuel in the housing tank, there is no need to force the fuel up into the tank against the weight of the fuel in the tank, as in the prior art system. It will be appreciated that the outlet of the pipe 130 could also be located below the surface of the fuel in the housing tank 102, however, the outlet should ideally not be located too far below the upper surface of the fuel in the housing tank, to minimize the pressure at the outlet. It will also be appreciated that the pipe 130 could, instead, be mounted on an outer surface of the housing tank 102. In tanker trucks having a double walled housing, the pipe 130 could run between the two walls. While the term pipe has been used to depict the fuel path 130, this could be either a rigid pipe or a flexible hose.

[0022] The invention contemplates any pump system connected to the pipe 130, but in a preferred embodiment a diaphragm pump is used. In another embodiment a centrifugal pump is used. The impeller 140 of the pump is mounted in a housing 142 which is in fluid communication with the pipe 130. In one embodiment, as shown in FIG. 3, a centrifugal pump 144 was used, made of a non-ferrous metal, in this case brass, and having a housing 142 with a male screw connector 146 receivable in a complementary female connector 148 welded to the wetline 104. The impeller 140 is driven by a turbine 150 mounted outside the housing 142, and connected to the impeller 140 through the housing wall 146. The turbine 150, in this embodiment, is driven by compressed from a compressed air source 152 connected through a hose 154 to the turbine 150. The compressed air source can be any conventional compressor as is commonly used to inflate tires or power tools.

[0023] It will be appreciated that the impeller 140 could, instead, be driven by a motor such as an electric motor connected to the impeller 140. However, such an arrangement is less desirable when flammable fluids are to be pumped, due to the danger of sparks and the possibility for a fire or explosion. It will be appreciated that, if the pipe 130 is wide enough to accommodate the impeller 140, the impeller 140 could be mounted directly in the pipe 130. It will also be appreciated that either the pipe 130, or housing 140, or the wetlines 104 will have to be provided with a valve for allowing air to enter the system as the fuel is sucked out of the wetlines 104. In the embodiment of FIG. 4, a valve 160 is provided in the housing 142.

[0024] Furthermore, in order to ensure that substantially all of the fuel in the wetlines 104 is removed, the housing 142 is preferably mounted at the lowest point on the wetlines 104. This may require the shape or attitude of the wetlines 104 to be adjusted. In the embodiment of FIG. 4, the housing 142 is mounted at an elbow 162 of the wetlines 104, wherein the wetlines 104 are shaped to define the elbow 162 as the lowest point on the wetlines 104.

[0025] The preferred embodiment of FIG. 4 uses compressed air as a propulsion source for the turbine 144, since compressed air is readily available. However, other fluid flow could, instead, be used to propel the turbine, such as water or oil flowing through the turbine.

[0026] While the invention was described specifically for propelling fuel from wetlines of a tanker truck into the housing tank of the truck, it has much broader applications. The use of an impeller and a turbine for driving the impeller, where the impeller is mounted in a housing or pipe and the turbine is preferably located outside the housing or pipe, has a wide range of possible applications. The invention can be used for conveying liquid along a pipe generally, whether or not the fluid is flammable. Especially the use of an air driven turbine presents an easy to implement solution due to the fact that compressed air sources are readily available. Also, by placing the turbine outside the pipe or housing for the impeller, none of the moving parts of the turbine are exposed to the liquid being pumped. This is especially useful when pumping corrosive or flammable liquids.

[0027] Thus, while the invention was described in detail with respect to a specific implementation, it has much broader scope, as defined by the claims to this application.

Claims

What is claimed, is:

1. A method of emptying wetlines associated with a housing tank of a tanker truck, comprising, pumping liquid in the wetlines into the housing tank, through a separated pipe extending from the wetlines to a location at or near the top of the housing tank.

2. A method of claim 1, wherein the separate pipe extends from the wetlines to a location above or near the highest surface of the liquid in the housing tank.

3. A method of claim 1, wherein the separate pipe extends along an inner surface of the housing tank.

4. A method of claim 1, wherein the separate pipe extends along an outer surface of the housing tank.

5. A method of claim 1, wherein the liquid is pumped using an impeller mounted in the pipe or in an impeller housing connected in fluid flow communication with the pipe.

6. A method of claim 5, wherein the impeller is driven by a turbine.

7. Means for emptying wetlines associated with a holding tank on a tanker truck, comprising a pipe extending from the wetlines to a location at or near the top of the housing tank, and a pump for pumping the liquid along the pipe into the housing tank.

8. Means according to claim 7, wherein the pump includes an impeller mounted in the pipe or in an impeller housing connected in fluid flow communication with the pipe.

9. Means according to claim 8, wherein the pump further includes a turbine which drives the impeller.

10. Means according to claim 8, wherein the turbine is located outside the pipe or any said impeller housing.

11. Means according to claim 8, wherein the turbine is operated by fluid flow.

12. Means according to claim 11, wherein the fluid is air, water, or oil.

13. Means of claim 12, wherein the turbine is operated by air flow from a compressed air source.

14. Means according to claim 7, wherein the separate pipe extends from the wetlines to a location above or near the highest surface of the liquid in the housing tank.

15. Means according to claim 7, wherein the separate pipe extends along an inner surface of the housing tank.

16. Means according to claim 7, wherein the separate pipe extends along an outer surface of the housing tank.

17. Means for propelling liquid through a pipe, comprising an impeller mounted in the pipe or a housing connected in fluid flow communication with the pipe, and a turbine, wherein the turbine is operated by air flow from a compressed air source.

18. Means for propelling liquid through a pipe, comprising an impeller mounted in the pipe or a housing connected in fluid flow communication with the pipe, and a turbine, wherein the turbine is located outside the pipe or any said housing.

19. Means for propelling liquid through a pipe, comprising an impeller mounted in the pipe or a housing connected in fluid flow communication with the pipe, and a turbine, wherein the turbine is operated by fluid flow from a separate fluid source.

20. Means according to claim 19, wherein the fluid is air, water, or oil.

21. Means according to claim 20, wherein the turbine is operated by air flow from a compressed air source.

22. Means according to claim 21, wherein the turbine is located outside the pipe or any said housing.