Laboratory gas suck-back prevention device

Abstract

The utility model discloses an anti-suck-back device for laboratory gas. The anti-suck-back device comprises a conveying main body and a floating ball, the conveying body is composed of a buffering cavity, an upper communicating pipe, a lower communicating pipe, a groove, an outer grinding opening and an inner grinding opening and is of an integrated glass structure. The buffering cavity is of a hollow containing structure with the upper portion narrow and the lower portion wide, and an arc-shaped groove is formed in the connecting position of the top end of the buffering cavity and the upper communication pipe. The floating ball is located in the buffering cavity and is of a hollow structure, the outer diameter of the floating ball is matched with the radian radius of the groove, and the upward sealing effect is achieved. And the lower conducting pipe partially extends into the buffer cavity to resist the floating ball, so that the lower conducting pipe is prevented from being blocked. Meanwhile, inner and outer grinding openings are arranged for connecting a reaction device. The device is mainly used for a laboratory gas reaction device, the main body is of an integrated structure, the leakproofness in the gas conveying process is ensured, the buffer cavity and the floating ball can effectively prevent liquid from being sucked back, the safety performance of laboratory gas reaction and gas cylinder use is greatly improved, and the device is easy to install and high in practicability.

Description

Technical Field

[0001] This utility model relates to the field of experimental apparatus technology, specifically designing a laboratory gas backflow prevention device. Background Technology

[0002] Laboratory reactions are diverse, often involving multiple phases, and some involve reactive gases or require inert gas protection. In reactions where gas is introduced into a liquid, the gas in the delivery tube may readily dissolve in the liquid due to its high solubility, causing a reduction in gas volume and creating a pressure difference. This pressure difference, combined with atmospheric pressure above the liquid surface, creates a negative pressure. Alternatively, changes in the reaction system's temperature and absorption rate can lead to negative pressure inside the gas delivery tube. The strong external atmospheric pressure can then force solvent into the delivery tube, causing backflow and blockage, posing a safety hazard. Furthermore, liquid blockage can prevent further gas flow into the reaction apparatus, potentially causing reaction termination or incomplete reaction.

[0003] Currently, there are many types of anti-backflow devices for laboratory gases, but most are assembled at the gas inlet, and the gas outlet is irregular or has an excessively large maximum diameter, making them only suitable for wide-mouth reaction vessels such as beakers. A simpler device, CN203316144U, connects to a rubber vent tube at the top, and the large-diameter end of a conical funnel at the bottom contacts the reaction liquid. When the reaction liquid is drawn back into the funnel, opening the vent cap increases the system pressure, and the reaction liquid returns to the container. Its structure is simple and its principle is clear. However, the large diameter of the end of the device limits the reaction vessel requirements; for example, it cannot be inserted into a three-necked flask, making it unsuitable for reactions requiring high sealing. Another example is the anti-backflow device CN112919613B, which offers good sealing and high efficiency. However, it is too large and has complex rotary spray and locking units, making it unsuitable for use with laboratory gas cylinders and their venting pipes. CN112361040B, through its drive shaft and sealing membrane design, effectively prevents the backflow of fluid, but it is prone to clogging and difficult to disassemble and clean. To solve the problem of backflow of reaction liquid during laboratory gas cylinder use, and to achieve cost savings, easy installation, convenient disassembly and cleaning, and improved versatility and safety, this utility model designs a laboratory gas anti-backflow device. Summary of the Invention

[0004] In response to the problem of backflow during the use of laboratory gas cylinders and to meet specific practical needs, this utility model provides a laboratory gas anti-backflow device. The device has a simple structure, is easier to assemble and disassemble, has more flexible installation location, a wider range of applications, and is more practical.

[0005] A laboratory gas anti-backflow device is characterized by comprising two parts: a conveying body (1) and a float (2). The conveying body (1) is composed of a buffer chamber (3), an upper guide tube (4), a lower guide tube (5), a groove (6), an outer ground joint (7), and an inner ground joint (8), forming an integral structure with smooth connections and no gaps, thus ensuring the airtightness of the device.

[0006] The upper guide tube (4) is located inside the outer ground joint (7), wherein the ratio of the outer diameter of the top end of the upper guide tube (4) to that of the outer ground joint (7) is 1:2-1:3. The presence of the outer ground joint (7) facilitates the connection of the reaction vessel with the ground joint. 1 / 3-3 / 4 of the upper guide tube (4) extends out of the outer ground joint (7). Without affecting the use of the outer ground joint (7), a venting tube can also be directly fitted, which improves the flexibility of the present invention.

[0007] The lower guide tube (5) is connected below the buffer chamber (3) and located in the middle of the inner ground joint (8). The presence of the lower guide tube (5) does not affect the use of the inner ground joint (8). The ratio of the outer diameter of the bottom end of the lower guide tube (5) and the inner ground joint (8) is 1:2-1:3. The presence of the inner ground joint (8) facilitates the insertion of the reaction vessel with the ground joint. 1 / 3-3 / 4 of the lower guide tube (5) extends out of the inner ground joint (8). The extended part can pass into the interior of the reaction vessel or below the liquid surface, which facilitates the reaction and absorption of gas. 1 / 6-1 / 4 of the lower guide tube (5) extends into the buffer chamber (3), which plays a certain role in resisting the float (2). Under the action of gas purging, it can jointly prevent the float (2) from blocking the lower guide tube (5), which facilitates the downward delivery of gas under normal conditions. The outer ground joint (7) and the inner ground joint (8) are located on the upper and lower exterior of the buffer chamber (3), respectively. They can be installed according to GB / T The ground joint standard of 21297-2007 and the ground joint size of different reaction vessels are used to set the size of the outer ground joint (7) and the inner ground joint (8) to enhance the universality of this utility model.

[0008] The buffer cavity (3) is located below the upper guide tube (4) and the outer ground joint (7); the buffer cavity (3) is a hollow cavity that is narrow at the top and wide at the bottom, with a ratio of 1:2 to 1:3 between the upper and lower diameters. It can be pear-shaped, conical, or inverted triangular, etc., with strong selectivity, meeting the requirements of fluid mechanics, guiding the fluid to flow more smoothly, reducing eddies and turbulence, and having stronger buffering capacity; the top slope of the buffer cavity (3) is 1:2 to 1:5.5, and the bottom slope is 1:0.3 to 1:1, which helps to optimize stress distribution, stabilize the structure, reduce damage, and extend service life; there is a groove (6) at the connection between the buffer cavity (3) and the upper guide tube (4); the groove (6) is arc-shaped, with the arc edge tangent to the top edge of the buffer cavity (3); the radius of the arc of the groove (6) matches the outer diameter of the float (2), with an arc between 110 and 170°, which can play the role of a slot and facilitate the fixation of the float (2).

[0009] The float (2) is located inside the buffer chamber (3) and is a hollow structure with an inner-outer diameter ratio of 0.85:1-0.95:1. It has a high vacancy rate, reduces weight, facilitates gas purging, and can float flexibly with the liquid surface. The ratio of the outer diameter of the float (2) to the inner diameter of the upper guide tube (4) and the lower guide tube (5) is 1.3:1:1-1.5:1:1. It can seal the upper guide tube (4) without falling out of the lower guide tube (5). The float (2) can fit completely into the groove (6). When the liquid level rises, it can block and seal the upper guide tube (4) upwards, preventing the liquid from flowing upwards.

[0010] The conveying body (1) is made of glass, which is not easily deformed, corrosion-resistant, rust-free, and has strong airtightness; the float (2) is made of polytetrafluoroethylene, which is relatively stable, does not easily react with gases and reaction liquids, has a long service life, and has little impact on the reaction.

[0011] In use, when gas is introduced through the upper guide pipe (4) of the conveying body (1), the float (2) is located at the bottom of the buffer chamber (3) due to gravity. Due to the influence of the lower guide pipe (5) extending into the buffer chamber (3) and the purging effect of the airflow, the float (2) does not block the lower guide pipe (5), and the gas can be normally conveyed downward to the reaction device. When the reaction liquid passes through the buffer chamber (3), due to the special properties of the gas and solvent, the pressure difference is too large. When the weight of the empty volume in the existing buffer chamber (3) is insufficient to offset the force generated by the pressure difference, the reaction liquid can still rise. At this time, the float (2) continues to move upward with the rise of the liquid level until it rises to a certain height. The float (2) then fits into the groove (6), blocking the upper guide pipe (4), and the liquid level stops rising. As the gas pressure inside the upper conduit (4) increases, the gas will slowly push the liquid surface and float (2) downwards. Once the float has moved to a certain depth, the gas can continue to be delivered, thus improving the safety of the gas cylinder during the reaction process. Meanwhile, the design of the extended portions of the upper conduit (4) and lower conduit (5), and the design of the outer ground joint (7) and inner ground joint (8), allow for the selection of either using conduits or directly connecting to the container via the ground joint, improving the flexibility of the device's use.

[0012] The beneficial effects of the present invention are:

[0013] 1. This utility model has a simple structure, is easy to install and disassemble, is easy to clean, and is highly practical.

[0014] 2. This utility model is universally applicable and flexible in installation location. Both the connecting pipe and the ground joint can be connected to the input / output device. When there is no requirement for the airtightness of the reaction and the reaction vessel is a wide-mouthed vessel, the connecting pipe can be used to connect to the device; when the reaction requires airtight conditions or the reaction vessel has a limited diameter, the ground joint can be used for installation and fixation.

[0015] 3. This utility model has two anti-backflow barriers: the buffering effect of the narrow-at-the-top and wide-at-the-bottom buffer cavity and the blocking effect of the hollow float ball, which can avoid safety hazards and improve safety performance.

[0016] 4. The main conveying body of this utility model is an integrated glass structure, which is corrosion resistant and has strong airtightness. The float is made of polytetrafluoroethylene, which is relatively stable and not prone to reaction. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings required in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model without any innovative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a half-sectional view of the present invention;

[0020] Figure 3 This is a schematic diagram illustrating the installation and application of this utility model;

[0021] Figure 4 This is a schematic diagram illustrating the working principle of this utility model;

[0022] The numbers in the diagram are as follows: 1 is the main conveyor body; 2 is the float; 3 is the buffer chamber; 4 is the upper guide pipe; 5 is the lower guide pipe; 6 is the groove; 7 is the outer ground joint; 8 is the inner ground joint. Detailed Implementation

[0023] The specific embodiments of this utility model are described in more detail below with reference to the accompanying drawings to help those skilled in the art to have a more accurate and in-depth understanding of the design concept and scheme of this utility model. The figures in the embodiments are consistent with the labels in the accompanying drawings for reference and comparison by relevant personnel. It should be understood that these examples are only used to illustrate this utility model and are not intended to limit the scope of this utility model.

[0024] according to Figure 1 and Figure 4 The schematic diagrams shown below illustrate different structural representations of this utility model, providing a complete and detailed understanding of the invention. A laboratory gas anti-backflow device includes: 1. a conveying body; 2. a float; 3. a buffer chamber; 4. an upper guide tube; 5. a lower guide tube; 6. a groove; 7. an outer ground joint; and 8. an inner ground joint. Installation and operation process:

[0025] When starting to use the device, the upper guide tube (4) is fitted with a venting hose or receives the gas discharged from the upper part of the device through the outer ground joint (7), and the device is fixed with a test tube clamp to keep it vertical. Similarly, the lower guide tube (5) is fitted with a venting hose or inserted into the reaction device with a matching ground joint through the inner ground joint (8). The gas flows smoothly through the device, and the installation is complete.

[0026] Application Example 1: The addition reaction of hydrogen sulfide and olefins requires the introduction of hydrogen sulfide gas. According to... Figure 3 As shown in the left figure, the ventilation hose carrying hydrogen sulfide gas has an inner ground joint, which is connected to this utility model through the outer ground joint (7). At the same time, the inner ground joint (8) of this utility model is connected and fixed to the outer ground joint of the three-necked flask of the reaction. The lower guide tube (5) extends below the surface of the reaction solution in the three-necked flask. The utility model is fixed with a test tube clamp to keep it vertical. The reaction begins. When the ventilation pressure is too low, the reaction liquid will be drawn back. Under the dual action of the buffer chamber (3) and the float (2), the liquid can be prevented from flowing back to the upper device, ensuring the safety of the reaction process. When the reaction is complete, the outer ground joint (7) and the inner ground joint (8) are pulled out, cleaned and dried, and the utility model is safely placed for the next use.

[0027] Application Example 2: In the preparation of hydrochloric acid, saturated brine is commonly used to absorb hydrogen chloride gas; this is a crucial step. According to... Figure 3 As shown in the right figure, the prepared hydrogen chloride gas is introduced into the ventilation hose and connected to the upper guide tube (4) of this invention. At the same time, the lower guide tube (5) is fitted with the ventilation hose, and the bottom of the ventilation hose is connected to an inverted triangular funnel, which is placed in a beaker containing saturated saline solution. When the concentration of hydrogen chloride gas decreases, a negative pressure is created in the triangular funnel, and the reaction liquid is drawn back into this invention. Under the dual action of the buffer chamber (3) and the float (2), the liquid can be prevented from flowing back into the reaction device, suppressing the backflow phenomenon and improving safety. When the reaction is complete, the ventilation tubes on the upper guide tube (4) and the lower guide tube (5) are pulled out, cleaned and dried, and the invention is safely stored for the next use.

Claims

1. A laboratory gas backflow prevention device, characterized in that: The device comprises two parts: a conveying body (1) and a float (2). The conveying body (1) consists of a buffer chamber (3), an upper guide tube (4), a lower guide tube (5), a groove (6), an outer grinding port (7), and an inner grinding port (8), forming an integrated structure. The upper guide tube (4) is located inside the outer grinding port (7) and extends out of the outer grinding port (7). The outer grinding port (7) is located above the buffer chamber (3). The buffer chamber (3) is located below the upper guide tube (4) and the outer grinding port (7), and a groove (6) exists at the connection point with the upper guide tube (4). The lower guide tube (5) is connected to the bottom of the buffer chamber (3). The lower guide tube (5) is located in the middle of the inner grinding port (8) and extends out of the inner grinding port (8). Part of the lower guide tube (5) extends into the buffer chamber (3). The inner grinding port (8) is located below the buffer chamber (3). The float (2) is located inside the buffer chamber (3).

2. The laboratory gas backflow prevention device according to claim 1, characterized in that: The ratio of the outer diameter of the top end of the upper guide tube (4) to the outer ground end (7) is 1:2-1:3; 1 / 3-3 / 4 of the upper guide tube (4) extends out of the outer ground end (7); the ratio of the outer diameter of the bottom end of the lower guide tube (5) to the inner ground end (8) is 1:2-1:3; 1 / 3-3 / 4 of the lower guide tube (5) extends out of the inner ground end (8); 1 / 6-1 / 4 of the lower guide tube (5) extends into the buffer cavity (3).

3. A laboratory gas backflow prevention device according to claim 1, characterized in that: The buffer cavity (3) is a hollow cavity that is narrow at the top and wide at the bottom, with the ratio of the upper and lower diameters being 1:2 to 1:3; the slope of the top of the buffer cavity (3) is 1:2 to 1:5.5, and the slope of the bottom is 1:0.3 to 1:1; the groove (6) is arc-shaped, with the arc edge tangent to the top edge of the buffer cavity (3); the radius of the arc of the groove (6) matches the outer diameter of the float (2), and the arc is between 110 and 170°.

4. A laboratory gas backflow prevention device according to claim 1, characterized in that: The float (2) is a hollow structure; the ratio of the inner and outer diameters of the float (2) is 0.85:1-0.95:1; the ratio of the outer diameter of the float (2) to the inner diameter of the upper guide tube (4) and the inner diameter of the lower guide tube (5) is 1.3:1:1-1.5:1:1; the float (2) and the groove (6) can fit together completely.

5. A laboratory gas backflow prevention device according to claim 1, characterized in that: The conveying body (1) is made of glass; the float (2) is made of polytetrafluoroethylene.

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