CN204738920U - A reciprocating piston pump for liquefied natural gas cylinders for automobiles - Google Patents

Abstract

The utility model discloses a reciprocating piston pump for liquefied natural gas cylinders for automobiles, which includes a closed pumping cavity and a piston body that can reciprocate in the pumping cavity. The liquid inlet of the cavity is blocked by a one-way valve, and the liquid outlet of the pumping cavity is blocked by a one-way valve two, wherein the blocking directions of the one-way valve one and one-way valve two are opposite, so When the piston moves toward the liquid inlet, the second check valve is opened, and when the piston moves against the liquid inlet, the first check valve is opened. The hydraulically driven piston pump is used to realize the automatic control of LNG extraction, and a closed pumping chamber is designed to facilitate the pressure control of the piston pump during the LNG extraction process. Compared with the self-pressurization method, after extracting LNG, the LNG bottle The internal residue is small, and the one-way valve design is adopted at the liquid inlet and outlet of the pumping chamber, which not only ensures the airtight environment of the pumping chamber but also prevents liquid backflow.

Description

A reciprocating piston pump for liquefied natural gas cylinders for automobiles

technical field

The utility model relates to LNG output equipment, in particular to a reciprocating piston pump for a liquefied natural gas cylinder for automobiles.

Background technique

LNG (liquefied natural gas) is liquefied natural gas, and its main component is methane. Because LNG has greater energy consumption and environmental protection advantages than gasoline or diesel, it is highly recommended by most automobile manufacturers and operators. However, compared with traditional automobile fuels, LNG has the disadvantage of low temperature, and it is difficult to control when filling and using. Early automobile LNG bottles used the self-pressurization method to output LNG, that is, the LNG was vaporized in the bottle to increase the pressure to press out the LNG. Insufficient gas or excessive gas supply, and the residual amount in the LNG cylinder is often large.

Although there are also documents disclosing the related technologies of cryogenic liquid pumps, there are still problems in backflow and pressure control if they are really applied to LNG whose storage temperature is generally around minus 162 degrees Celsius.

Utility model content

The purpose of the utility model is to address the above problems and provide a reciprocating piston pump for automotive LNG bottles that can prevent fuel backflow and facilitate pressure control.

In order to achieve the above purpose, the utility model adopts the following technical solutions: a reciprocating piston pump for liquefied natural gas cylinders for automobiles, including a closed pumping chamber and a piston body that can reciprocate in the pumping chamber. The piston body is driven by hydraulic pressure, and is blocked by a one-way valve at the liquid inlet of the pumping cavity, and is blocked by a one-way valve two at the liquid outlet of the pumping cavity, wherein the one-way valve one and one-way valve The blocking direction of the valve two is opposite, the one-way valve two is opened when the piston body moves toward the liquid inlet, and the one-way valve one is opened when the piston body moves against the liquid inlet. A piston pump structure driven by hydraulic pressure is adopted, and a closed pumping cavity is formed, so that the pressure change in the pumping cavity depends on the movement of the piston body, which makes the pressure in the pumping cavity easy to control, so that The process of pumping LNG is also easy to control. At the same time, a one-way valve is used at the liquid inlet and the liquid outlet of the pumping cavity to prevent the liquid from flowing back.

Preferably, when the piston body moves to the top toward the liquid inlet, the piston body occupies at least 90% of the internal space of the pumping cavity. When the piston body moves against the liquid inlet, a vacuum space appears in the pumping chamber. When the piston body reaches the top, the larger the internal space of the pumping chamber is, the greater the pressure difference between the pressure in the pumping chamber and the outside world can be. Larger and easier to control.

Preferably, a channel for transporting liquid is provided between the liquid outlet and the pumping cavity, and the channel is L-shaped and accommodates stagnation of liquid. Due to the high-speed movement of the piston body, the channel for conveying liquid is designed as an L-shaped stagnation space for buffering.

Preferably, the piston body is made of steel, which contains 20% by weight of chromium and 11% by weight of nickel.

Preferably, the head end of the piston body is a labyrinth seal structure.

Preferably, the one-way valve includes a T-shaped valve body and a valve seat, and the T-shaped valve body and the valve seat are connected by a low-temperature-resistant spring, and the valve seat is located in the liquid inlet channel. The T-shaped valve body includes a round cover, which is located in the pumping cavity and is pulled toward the liquid inlet by the spring one and blocked.

As a preference, said one-way valve 2 includes a spherical valve body, the spherical valve body is connected to spring 2, and one end of spring 2 is fixed in the channel outside the liquid outlet and presses the spherical valve body to the liquid outlet, The liquid outlet is blocked by the spherical surface of the spherical valve body.

Compared with the prior art, the utility model has the advantages of adopting a hydraulically driven piston pump to realize automatic control of LNG extraction, and designing a closed pumping chamber to facilitate the pressure control of the piston pump during LNG extraction. Compared with the self-pressurization method, after extracting LNG, there is less residue in the LNG bottle, and the one-way valve design is adopted at the liquid inlet and outlet of the pumping chamber, which not only ensures the airtight environment of the pumping chamber but also Can prevent liquid backflow. Elastic designs are used for the one-way valves, and different sealing surfaces are designed for different blocking directions of the two one-way valves.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the utility model. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is the structural representation of the utility model;

Fig. 2 is an enlarged schematic view of the closed cavity of the present invention.

Detailed ways

The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all embodiments. Based on the embodiments in the utility model, all other embodiments obtained by persons of ordinary skill in the art without creative efforts belong to the protection scope of the utility model.

As shown in Figures 1 and 2, a reciprocating piston pump for liquefied natural gas cylinders for automobiles includes a hydraulic pump 1 as a power unit, and the hydraulic pump is connected to a piston body 3 through a connecting rod 2, wherein the piston body 3 is closed The pumping cavity 4 is reciprocating. In order to prevent the LNG liquid entering the pumping cavity from leaking through the piston body, the piston body 3 adopts a labyrinth sealing structure. The liquid inlet 12 of the pumping cavity 4 communicates with the netted liquid inlet head 5, and the liquid inlet head 5 is buried under the LNG liquid surface in the LNG bottle. The liquid inlet 12 of the pumping cavity is blocked by a one-way valve, and the liquid outlet 13 of the pumping cavity is blocked by a one-way valve two, wherein the one-way valve one and one-way valve two are sealed. The blocking direction is opposite.

The hydraulic pump 1 drives the piston body 3 to move. When the piston body moves towards the liquid inlet, the check valve 2 is opened, and when the piston body moves against the liquid inlet, the check valve 1 is opened. Due to the adoption of hydraulic drive mode, the automatic control of LNG liquid pumping is realized, and the closed pumping cavity is designed, so that the pressure change in the pumping cavity depends on the movement of the piston body, which in turn makes the pressure in the pumping cavity change. It is easy to control, so that the process of pumping LNG liquid is also easy to control. At the same time, compared with the self-pressurization method, after the LNG liquid is extracted, the residue in the LNG bottle is small. Elastic one-way valves are used at the liquid inlet and outlet of the pumping chamber to prevent the LNG liquid from flowing back.

Due to the low-temperature characteristics of LNG liquid, its fluidity is relatively low. In the case of hydraulic drive, this embodiment is provided with a channel for transporting liquid between the liquid outlet 13 and the pumping cavity. 6. The channel is L-shaped and accommodates liquid retention as a buffer.

Preferably, the piston body is made of steel, which contains 20% by weight of chromium and 11% by weight of nickel. Piston body type The important parts of this utility model, in order to adapt to the characteristics of LNG liquid, optimize the design of the piston body material, mainly to increase the content of chromium and nickel, in which chromium is added to increase corrosion resistance, and nickel is increased to increase corrosion resistance. Low temperature resistance, after several tests, the steel material in this embodiment is used, and the piston body can be used normally for at least ten years.

As a preferred embodiment of the one-way valve, refer to FIG. 2, the one-way valve includes a T-shaped valve body 7 and a valve seat 9, and a low-temperature-resistant spring passes between the T-shaped valve body and the valve seat. 10 connection, the valve seat 9 is located in the liquid inlet channel, the T-shaped valve body includes a round cover part 71, the round cover part 71 is located in the pumping cavity 4 and is supported by the spring one 10 is pulled toward the liquid inlet 12 and blocked. When the piston body 3 moves towards the liquid inlet, the pressure in the pumping chamber 4 increases, and the dome 71 maintains a sealing relationship with the liquid inlet, and when the piston body 3 moves against the liquid inlet , the pressure in the pumping cavity 4 decreases, and under the action of the pressure difference, the spring 10 is compressed, and the dome 71 is not sealed with the liquid inlet, and the one-way valve is opened .

As a preferred embodiment of the check valve 2, refer to Fig. 2, the check valve 2 includes a spherical valve body 8, the spherical valve body is connected to a spring 2 11, and one end of the spring 2 11 is fixed to the channel outside the liquid outlet and press the spherical valve body to the liquid outlet, and the spherical surface of the spherical valve body 8 blocks the liquid outlet. When the piston body 3 moves against the liquid inlet, the pressure in the pumping cavity 4 decreases, and under the action of the pressure difference and the spring 11, the spherical surface of the spherical valve body 8 and the liquid outlet 13 remain sealed. When the piston body 3 moves towards the liquid inlet, the pressure in the pumping chamber 4 increases, the spring 2 11 shown is compressed, and the spherical surface of the spherical valve body 8 and the liquid outlet are no longer sealed, LNG liquid is pumped out from the liquid outlet.

The above descriptions are only preferred embodiments of the utility model, and are not intended to limit the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model shall be included in the utility model. within the scope of protection.

Claims (7)

1. the reciprocating piston pump of an automobile liquefied natural gas bottle, it is characterized in that: comprise closed pumping cavity and can in described pumping cavity reciprocating piston body, this piston body is by hydraulic driving, at the liquid entering hole place of pumping cavity by one-way valve one shutoff, at the liquid outlet place of pumping cavity by one-way valve two shutoff, wherein the shutoff direction of one-way valve one and one-way valve two is contrary, described piston body opens one-way valve two when liquid entering hole moves, opens one-way valve one when the reverse liquid entering hole of described piston body moves.

2. the reciprocating piston pump of automobile liquefied natural gas bottle according to claim 1, is characterized in that: when described piston body moves to top towards liquid entering hole, this piston body occupies the inner space at least 90% of described pumping cavity.

3. the reciprocating piston pump of automobile liquefied natural gas bottle according to claim 2, is characterized in that: be provided with the passage for carrying liquid between described liquid outlet and described pumping cavity, and this passage is L shape and receiving fluids is detained.

4. the reciprocating piston pump of automobile liquefied natural gas bottle according to claim 1, is characterized in that: the material that described piston body adopts is steel, and its weight percentage containing chromium is 20%, and nickeliferous weight percentage is 11%.

5. the reciprocating piston pump of the automobile liquefied natural gas bottle according to claim 1 or 4, is characterized in that: piston body head end is labyrinth seal structure.

6. the reciprocating piston pump of automobile liquefied natural gas bottle according to claim 1, it is characterized in that: described one-way valve one comprises T-shaped valve body and valve seat, connected by low temperature resistant spring one between T-shaped valve body and valve seat one, described valve seat is positioned at feed pathway, described T-shaped valve body comprises dome portion, and this dome portion is positioned at described pumping cavity and pulls to described liquid entering hole and shutoff by described spring one.

7. the reciprocating piston pump of automobile liquefied natural gas bottle according to claim 1, it is characterized in that: described one-way valve two comprises sphere valve body, this sphere valve body linking springs two, sphere valve body is pressed to described liquid outlet, by the liquid outlet described in the sphere shutoff of sphere valve body in the passage that liquid outlet outside is fixed in spring two one end.