Low-temperature liquid storage tank with filling balance adjusting device

Abstract

The utility model discloses a low-temperature liquid storage tank with a filling balance adjusting device, which comprises a tank car gas inlet and outlet pipe, an upper end port of which is positioned at the inner top end of the storage tank; the tank car gas inlet and outlet valve is arranged on the tank car gas inlet and outlet pipe; a port at the upper end of the tank car liquid inlet and outlet pipe is positioned at the inner bottom end of the storage tank; the tank car liquid inlet and outlet valve is arranged on the tank car liquid inlet and outlet pipe; a pressure balance assembly is arranged on the storage tank, one end of the pressure balance assembly is connected to the tank car gas inlet and outlet pipe, and the other end of the pressure balance assembly is connected to the tank car liquid inlet and outlet pipe. The tank cars fill liquid into the low-temperature storage tanks or the low-temperature storage tanks supply liquid to the tank cars, and particularly for the two tank cars, the liquid phase and the gas phase automatically achieve pressure balance; the lower liquid inlet valve and the upper liquid inlet and outlet valve realize automatic liquid inlet control of the low-temperature storage tank; the gas balance pipe realizes pressure balance of two or more low-temperature storage tanks to realize liquid supply; the upper liquid inlet and outlet pipe guides fluid on the lower portion of the inner groove body to enter, and the side wall holes achieve fluid balance drainage.

Description

Technical Field

[0001] The utility model belongs to the technical field of low-temperature liquid storage tanks, and in particular relates to a low-temperature liquid storage tank provided with a filling balance regulating device. Background Art

[0002] Cryogenic liquid storage tanks have a wide range of application scenarios in many fields. First, in industrial production and daily life, cryogenic liquid storage tanks are used to store and supply cryogenic liquefied gases, such as liquid nitrogen, liquid oxygen, liquid argon and liquid carbon dioxide. These gases have important applications in the steel, chemical, medical and other industries. Secondly, in the aerospace field, cryogenic liquid storage tanks are used in power systems such as hydrogen-oxygen rocket engines, liquid oxygen-kerosene engines, and high-pressure and low-temperature tests of components such as valves, pipelines, and compensators. In addition, cryogenic liquid storage tanks also play a role in scientific research, food freezing and other fields.

[0003] The Chinese patent document with publication number CN204127664U discloses a vertical cryogenic liquid storage tank, including a tank body, a supercharger is installed at the bottom center of the tank body, the supercharger is provided with a supercharger input pipe and a supercharger output pipe, the supercharger input pipe is connected to the tank body through an input pressure regulating valve, a supercharger opening valve and a supercharger input valve in sequence, a bottom filling valve is installed on the pipeline between the supercharger opening valve and the supercharger input valve; the supercharger output pipe is connected to the tank body through an output pressure regulating valve and a supercharger output valve respectively, and a top filling valve is also installed at the end of the supercharger output valve away from the tank body; a branch pipeline is opened on the pipeline between the top filling valve and the bottom filling valve, and a filling pipe discharge valve and a filling joint are arranged on the branch pipeline in sequence.

[0004] The above patent solution has only one filling port, which cannot realize the simultaneous filling of multiple tank trucks. The temporary addition of a filling port does not comply with safety regulations. The temporarily added filling port can only be changed externally, and the interior of the storage tank cannot be modified. The filling balance requirement cannot be met, and automatic filling adjustment cannot be achieved. Utility Model Content

[0005] In order to overcome the technical problems in the prior art that the low-temperature liquid storage tank has only one filling port and cannot realize simultaneous filling of multiple tank trucks, and the temporary increase of filling ports does not comply with safety regulations and cannot balance the pressure between the gas phase and the liquid phase; one purpose of the utility model is to provide a low-temperature liquid storage tank with a filling balance adjustment device, by arranging a tank truck gas inlet and outlet pipe with an upper end port located at the top of the storage tank and a tank truck liquid inlet and outlet pipe with an upper end port located at the bottom of the storage tank, and arranging a pressure balance component between the tank truck gas inlet and outlet pipe and the tank truck liquid inlet and outlet pipe, pressure balance can be achieved while two tank trucks are filling.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions: a low-temperature liquid storage tank provided with a filling balance and adjustment device, comprising a tank truck gas inlet and outlet pipe, the upper end port of the tank truck gas inlet and outlet pipe is located at the inner top end of the storage tank; a tank truck gas inlet and outlet valve, the tank truck gas inlet and outlet valve is arranged on the tank truck gas inlet and outlet pipe; a tank truck liquid inlet and outlet pipe, the upper end port of the tank truck liquid inlet and outlet pipe is located at the inner bottom end of the storage tank; a tank truck liquid inlet and outlet valve, the tank truck liquid inlet and outlet valve is arranged on the tank truck liquid inlet and outlet pipe; wherein a pressure balance assembly is arranged on the storage tank, one end of the pressure balance assembly is connected between the tank truck gas inlet and outlet valve and the upper end port of the tank truck gas inlet and outlet pipe, and the other end is connected between the tank truck liquid inlet and outlet valve and the upper end port of the tank truck liquid inlet and outlet pipe.

[0007] Furthermore, the pressure balancing assembly includes a regulating tube body, the two ends of which are respectively connected to the gas inlet and outlet pipes of the tank truck and the liquid inlet and outlet pipes of the tank truck; a self-boosting device, which is arranged on the regulating tube body and vaporizes the liquid into gas; a boosting gas phase valve, which is arranged on the regulating tube body and located between the connection between the self-boosting device and the gas inlet and outlet pipes of the tank truck; and a boosting liquid phase valve, which is arranged on the regulating tube body and located between the connection between the self-boosting device and the liquid inlet and outlet pipes of the tank truck.

[0008] When filling the storage tank with liquid, two tank trucks are respectively connected to the tank truck's gas inlet and outlet pipes, and the two tank trucks fill the storage tank with liquid at the same time; when the storage tank supplies liquid to the outside, one tank truck is connected to the tank truck's gas inlet and outlet pipes, and the other tank truck is connected to the tank truck's liquid inlet and outlet pipes, so that the storage tank supplies liquid to the two tank trucks at the same time; if only one tank truck is used to fill or supply liquid, the tank truck for the first filling should be connected to the tank truck's gas inlet and outlet pipe for filling, and the tank truck can be connected to the tank truck's liquid inlet and outlet pipes when filling liquid during use.

[0009] Furthermore, an upper liquid inlet and outlet pipe is provided in the storage tank; the upper liquid inlet and outlet pipe is in an inverted U-shape; one port of the upper liquid inlet and outlet pipe is located at the bottom of the storage tank, and the other port of the upper liquid inlet and outlet pipe passes through the bottom of the storage tank; an upper liquid inlet and outlet valve is provided on the upper liquid inlet and outlet pipe and located outside the storage tank; a side wall hole connected to the upper liquid inlet and outlet pipe is provided on the upper side wall of the upper liquid inlet and outlet pipe; the height of the side wall hole is greater than the height of the upper inlet of the fullness measuring tube.

[0010] The upper liquid inlet and outlet pipe is in an inverted U-shape so as to change the position of the liquid on the storage tank. When the internal port is arranged below the filling level of the storage tank, the upper liquid inlet and outlet pipe is filled with liquid medium during operation, which can effectively seal and balance the internal and external pressures of the upper liquid inlet and outlet pipe.

[0011] If the internal port of the upper liquid inlet and outlet pipe is directly inserted into the top of the storage tank, the medium cannot be discharged when the liquid level in the storage tank is low, and the internal and external pressures of the upper liquid inlet and outlet pipe cannot be automatically balanced according to the liquid level changes; if the upper liquid inlet and outlet pipe is directly installed at the bottom of the storage tank, it cannot play the role of self-sealing of the liquid level air pressure, and cannot achieve the function of self-balancing of the inlet and outlet liquid.

[0012] The purpose of setting the side wall holes is to effectively control and adjust the liquid pressure and gas pressure inside the upper liquid inlet and outlet pipes.

[0013] When the storage tank supplies liquid to the outside, the pressure balance component ensures the safety of external liquid supply, and can replace the function of the regulating valve to achieve liquid outlet balance, achieve pressure balance in the storage tank, and prevent overpressure in the storage tank. The self-boosting device does not require electric or hydraulic mechanism regulation to achieve effective balance of liquid filling in the tank truck.

[0014] Specifically, the storage tank includes an outer tank body, a filler, and an inner tank body which are arranged in sequence from the outside to the inside; the upper liquid inlet and outlet pipe includes an inner tube body arranged inside the inner tank body, a connecting tube body arranged on the wall of the inner tank body, and an outer tube body arranged outside the inner tank body; the inner tube body is arranged in an inverted U shape; the connecting tube body connects the inside and outside of the inner tank body; the inner tube body and the outer tube body are respectively welded and connected to the two ends of the connecting tube body.

[0015] Specifically, the inner tube body is close to the inner wall of the inner tank body; and the inner wall of the inner tank body is provided with at least one tube clamp for fixing the inner tube body.

[0016] Preferably, both ends of the inner tube body are respectively provided with extension tubes bent toward the central position of the bottom of the storage tank.

[0017] Preferably, the diameter of the side wall hole is one third of the diameter of the inner tube body.

[0018] Furthermore, a gas balance pipe is provided on the storage tank; one end of the gas balance pipe is connected to the inner top of the storage tank; and pressure balance is achieved by interconnecting the gas balance pipes of multiple storage tanks.

[0019] Furthermore, a sewage discharge pipe is provided on the storage tank; one end of the sewage discharge pipe is connected to the inner bottom of the storage tank; a lower liquid inlet pipe is provided below the storage tank; the lower liquid inlet pipe is connected to the inner bottom of the storage tank; and a lower liquid inlet valve is provided on the lower liquid inlet pipe.

[0020] Specifically, the tank truck gas inlet and outlet pipe, the tank truck liquid inlet and outlet pipe, the upper liquid inlet and outlet pipe, the lower liquid inlet pipe, the sewage pipe, and the gas balance pipe are arranged in sequence from left to right below the storage tank.

[0021] Compared with the prior art, the beneficial effects of the utility model are: when liquid is automatically supplied from a tank truck to a low-temperature storage tank or from a low-temperature storage tank to a tank truck, especially when two tank trucks are simultaneously filling or supplying liquid to a low-temperature storage tank, the liquid phase and the gas phase automatically achieve pressure balance; the lower liquid inlet valve and the upper liquid inlet and outlet valves realize automatic liquid inlet control of the low-temperature storage tank; the gas balance pipe realizes pressure balance of two or more low-temperature storage tanks to realize liquid supply; the upper liquid inlet and outlet pipe guides the fluid at the lower part of the inner tank body to enter, and the side wall holes realize fluid balanced drainage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A structural diagram of the pipeline design of the utility model;

[0023] Figure 2 This is a structural diagram of the upper liquid inlet and outlet pipes of the utility model;

[0024] Figure 3 It is a schematic diagram of the arrangement of each pipeline of the utility model in the circumferential direction;

[0025] Figure 4 It is a schematic diagram of the arrangement of each pipeline of the utility model in the vertical direction.

[0026] In the figure: 11, tank truck gas inlet and outlet pipe; 12, tank truck gas inlet and outlet valve; 21, tank truck liquid inlet and outlet pipe; 22, tank truck liquid inlet and outlet valve; 31, boosting liquid phase valve; 32, boosting gas phase valve; 33, self-boosting device; 41, lower liquid inlet pipe; 411, lower liquid inlet valve; 42, upper liquid inlet and outlet pipe; 421, side wall hole; 422, upper liquid inlet and outlet valve; 423, extension pipe; 43, pipe clamp; 5, gas balance pipe; 6, fullness measuring pipe; 7, sewage pipe. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0028] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific protection scope of the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0030] In the present invention, unless otherwise specified and limited, the terms "setting", "installation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] See also Figure 1-Figure 4 A low-temperature liquid storage tank provided with a filling balance adjustment device includes a tank truck gas inlet and outlet pipe 11, the upper end port of the tank truck gas inlet and outlet pipe 11 is located at the inner top end of the storage tank; a tank truck gas inlet and outlet valve 12, the tank truck gas inlet and outlet valve 12 is arranged on the tank truck gas inlet and outlet pipe 11; a tank truck liquid inlet and outlet pipe 21, the upper end port of the tank truck liquid inlet and outlet pipe 21 is located at the inner bottom end of the storage tank; a tank truck liquid inlet and outlet valve 22, the tank truck liquid inlet and outlet valve 22 is arranged on the tank truck liquid inlet and outlet pipe 21; a pressure balance component is arranged on the storage tank.

[0032] The pressure balancing assembly includes a regulating tube body, the two ends of which are respectively connected to the tank truck gas inlet and outlet pipe 11 and the tank truck liquid inlet and outlet pipe 21; a self-boosting device 33, which is arranged on the regulating tube body, and is a low-temperature liquid vaporizer used to vaporize liquid into gas; a boosting gas phase valve 32, which is arranged on the regulating tube body and is located between the connection between the self-boosting device 33 and the tank truck gas inlet and outlet pipe 11; a boosting liquid phase valve 31, which is arranged on the regulating tube body and is located between the connection between the self-boosting device 33 and the tank truck liquid inlet and outlet pipe 21; one end of the regulating tube body is connected between the tank truck gas inlet and outlet valve 12 and the upper end port of the tank truck gas inlet and outlet pipe 11, and the other end is connected between the tank truck liquid inlet and outlet valve 22 and the upper end port of the tank truck liquid inlet and outlet pipe 21.

[0033] An upper liquid inlet and outlet pipe 42 is provided in the storage tank; the upper liquid inlet and outlet pipe 42 is in an inverted U-shape; one port of the upper liquid inlet and outlet pipe 42 is located at the bottom of the storage tank, and the other port of the upper liquid inlet and outlet pipe 42 passes through the bottom of the storage tank; an upper liquid inlet and outlet valve 422 is provided on the upper liquid inlet and outlet pipe 42 and located outside the storage tank; a side wall hole 421 connected to the upper liquid inlet and outlet pipe 42 is provided on the upper side wall of the upper liquid inlet and outlet pipe 42; the height of the side wall hole 421 is greater than the height of the upper inlet of the fullness measuring tube 6.

[0034] The storage tank includes an outer tank body, a filler, and an inner tank body which are arranged in sequence from the outside to the inside; the upper liquid inlet and outlet pipe 42 includes an inner tube body arranged inside the inner tank body, a connecting tube body arranged on the wall of the inner tank body, and an outer tube body arranged outside the inner tank body; the inner tube body is arranged in an inverted U shape; the connecting tube body connects the inside and outside of the inner tank body; the inner tube body and the outer tube body are respectively welded and connected to the two ends of the connecting tube body.

[0035] The inner tube body is close to the inner wall of the inner tank body; the inner wall of the inner tank body is provided with at least one tube clamp 43 for fixing the inner tube body; both ends of the inner tube body are provided with extension tubes 423 bent toward the central position of the bottom of the storage tank; the diameter of the side wall hole 421 is one third of the diameter of the inner tube body

[0036] A gas balance pipe 5 is provided on the storage tank; one end of the gas balance pipe 5 is connected to the inner top of the storage tank; a sewage pipe 7 is provided on the storage tank; one end of the sewage pipe 7 is connected to the inner bottom of the storage tank; a lower liquid inlet pipe 41 is provided below the storage tank; the lower liquid inlet pipe 41 is connected to the inner bottom of the storage tank; a lower liquid inlet valve 411 is provided on the lower liquid inlet pipe 41; the tank truck gas inlet and outlet pipe 11, the tank truck liquid inlet and outlet pipe 21, the upper liquid inlet and outlet pipe 42, the lower liquid inlet pipe 41, the sewage pipe 7, and the gas balance pipe 5 are arranged in sequence from left to right below the storage tank.

[0037] Generally, a storage tank is filled with liquid through one filling port, and multiple tank trucks cannot be filled and supplied with liquid at the same time. In order to enable multiple tank trucks to quickly fill the storage tank through balance adjustment and realize automatic liquid filling safety adjustment, two liquid filling ports (tank truck gas inlet and outlet pipes 11 and tank truck liquid inlet and outlet pipes 21) are designed with their own filling ports. Through pipeline balance design, a filling balance adjustment device (upper liquid inlet and outlet pipes 42) is added inside the storage tank. It is made of bent steel pipe, and a balance hole (side wall hole 421) is opened at the top of the steel pipe by design and calculation to realize the automatic adjustment function of the pressure balance between the gas phase and liquid phase space inside the storage tank during the filling process.

[0038] When filling liquid, the initial filling liquid is connected by the tank truck gas inlet and outlet pipe 11, and the tank truck fills the storage tank with liquid. After the liquid level inside reaches a certain height, the liquid is increased by the booster liquid phase valve 31 and the self-booster 33 gasification pressure, which increases the pressure inside the storage tank and slows down the filling speed. At this time, the liquid filling starts through the tank truck liquid inlet and outlet pipe 21. The two tank trucks are filled with liquid at the same time, filling the storage tank with liquid, increasing the amount of liquid entering and offsetting the increase in the pressure of the internal gasified gas. At this time, the pressure balance component can discharge the internal liquid from the gas balance pipe 5 to the outside, playing a regulating role, thereby completing the filling and liquid supply. When the liquid level reaches the highest liquid level of the storage tank, the liquid level control device set by the system automatically alarms, and the filling can be stopped at this time.

[0039] Specifically, when two tank trucks are simultaneously filling liquid into the cryogenic liquid storage tank, the two tank trucks are respectively connected to the tank truck gas inlet and outlet pipes 11, and the two tank trucks are simultaneously filling the storage tank. When the liquid level in the storage tank rises to a certain height, the liquid is filled too quickly into the storage tank, which makes the internal gas phase space smaller. The filling process needs to increase the filling pressure. At this time, the gasification effect of the liquid flowing through the self-boosting device 33 is used to balance the internal gas phase pressure of the storage tank with the external filling liquid pressure, so as to slow down the instantaneous high pressure effect formed inside the storage tank and realize a smooth balanced filling process. At this time, the gas pressure at the side wall hole 421 of the upper inlet and outlet pipe 42 becomes smaller, and the liquid can quickly enter the upper inlet and outlet pipe 42 from the bottom of the storage tank.

[0040] When the cryogenic liquid storage tank supplies or discharges liquid, one tank truck is connected to the tank truck gas inlet and outlet pipe 11, and the other tank truck is connected to the tank truck liquid inlet and outlet pipe 21. When the liquid level in the storage tank drops to a certain height, the liquid is filled too quickly to enlarge the internal gas phase space, and an instantaneous vacuum state is formed during the liquid supply process. At this time, the gasification effect of the liquid flowing through the self-boosting device 33 is used to balance the internal gas phase pressure of the container with the external liquid supply pressure, so as to achieve a smooth balanced liquid supply process. At this time, the gas pressure at the side wall hole 421 of the upper liquid inlet and outlet pipe 42 increases, slowing down the flow rate of the liquid from the bottom of the storage tank into the upper liquid inlet and outlet pipe 42.

[0041] The above description is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the patent scope of the present invention.

Claims

1. A cryogenic liquid storage tank provided with a filling balance regulating device, characterized in that: It includes a tank truck gas inlet and outlet pipe, the upper end port of the tank truck gas inlet and outlet pipe is located at the inner top end of the storage tank; A tank truck gas inlet and outlet valve, wherein the tank truck gas inlet and outlet valve is arranged on the tank truck gas inlet and outlet pipe; A tank truck liquid inlet and outlet pipe, the upper end port of the tank truck liquid inlet and outlet pipe is located at the inner bottom end of the storage tank; a tank truck liquid inlet and outlet valve, the tank truck liquid inlet and outlet valve is arranged on the tank truck liquid inlet and outlet pipe; Among them, a pressure balancing assembly is provided on the storage tank, one end of the pressure balancing assembly is connected between the gas inlet and outlet valve of the tank truck and the upper end port of the gas inlet and outlet pipe of the tank truck, and the other end is connected between the liquid inlet and outlet valve of the tank truck and the upper end port of the liquid inlet and outlet pipe of the tank truck.

2. The storage tank according to claim 1, characterized in that: The pressure balance assembly includes a regulating tube body, and the two ends of the regulating tube body are respectively connected to the tank truck gas inlet and outlet pipes and the tank truck liquid inlet and outlet pipes; A self-pressurizer, which is arranged on the regulating tube body and vaporizes the liquid into gas; A boost gas phase valve, which is arranged on the regulating pipe body and is located between the connection between the self-booster and the gas inlet and outlet pipes of the tank truck; A pressurized liquid phase valve is arranged on the regulating pipe body and is located between the connection between the self-boosting device and the liquid inlet and outlet pipes of the tank truck.

3. The storage tank according to claim 2, characterized in that: An upper liquid inlet and outlet pipe is arranged in the storage tank; the upper liquid inlet and outlet pipe is arranged in an inverted U-shape; one port of the upper liquid inlet and outlet pipe is located at the bottom of the storage tank, and the other port of the upper liquid inlet and outlet pipe passes through the bottom of the storage tank; an upper liquid inlet and outlet valve is arranged on the upper liquid inlet and outlet pipe and located outside the storage tank; a side wall hole connected to the upper liquid inlet and outlet pipe is arranged on the upper side wall of the upper liquid inlet and outlet pipe; the height of the side wall hole is greater than the height of the upper inlet of the fullness measuring tube.

4. The storage tank according to claim 3, characterized in that: The storage tank includes an outer tank body, a filler, and an inner tank body which are arranged in sequence from the outside to the inside; the upper liquid inlet and outlet pipe includes an inner tube body arranged inside the inner tank body, a connecting tube body arranged on the wall of the inner tank body, and an outer tube body arranged outside the inner tank body; the inner tube body is arranged in an inverted U shape; the connecting tube body connects the inside and outside of the inner tank body; the inner tube body and the outer tube body are respectively welded and connected to the two ends of the connecting tube body.

5. The storage tank according to claim 4, characterized in that: The inner tube body is close to the inner wall of the inner tank body; the inner wall of the inner tank body is provided with at least one tube clamp for fixing the inner tube body.

6. The storage tank according to claim 4, characterized in that: Both ends of the inner tube body are respectively provided with extension tubes bent toward the central position of the bottom of the storage tank.

7. The storage tank according to claim 4, characterized in that: The diameter of the side wall hole is one third of the diameter of the inner tube body.

8. The storage tank according to any one of claims 3 to 7, characterized in that: The storage tank is provided with a gas balance pipe; one end of the gas balance pipe is connected to the inner top of the storage tank; and pressure balance is achieved by interconnecting the gas balance pipes of multiple storage tanks.

9. The storage tank according to claim 8, characterized in that: The storage tank is provided with a sewage discharge pipe; one end of the sewage discharge pipe is connected to the inner bottom of the storage tank; a lower liquid inlet pipe is provided below the storage tank; the lower liquid inlet pipe is connected to the inner bottom of the storage tank; a lower liquid inlet valve is provided on the lower liquid inlet pipe.

10. The storage tank according to claim 9, characterized in that: The bottom of the storage tank is arranged from left to right in sequence with the tank truck gas inlet and outlet pipe, the tank truck liquid inlet and outlet pipe, the upper liquid inlet and outlet pipe, the lower liquid inlet pipe, the sewage pipe, and the gas balance pipe.

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