A burette protection cover for an automatic potentiometric titrator

Abstract

The utility model discloses a burette protection cover of automatic electric potential titrator, including cover body, the cover body is the cylinder structure of two ends through, its inside is equipped with soda lime annular belt. The utility model discloses through cover body insulation burette external environment's air flow, through placing in the soda lime placement area's soda lime can be adsorbed to the carbon dioxide in the protection cover, and the burette of automatic electric potential titrator carries out the test in the environment without carbon dioxide, effectively prevents the glass burette in piston downward operation titration test, and the residual trace potassium hydroxide isopropyl alcohol solution and the carbon dioxide in air on the glass burette upper portion contact and take place chemical reaction.

Description

Technical Field

[0001] This utility model relates to the field of potentiometric titrator technology, and in particular to a burette protective cover for an automatic potentiometric titrator. Background Technology

[0002] An automatic potentiometric titrator is an instrument that uses potentiometric titration to determine the titration endpoint by measuring the change in potential during the titration process. It is mainly used in chemical analysis in universities, research institutions, and various industries such as petrochemicals, pharmaceuticals, and metallurgy. For example, the Metrohm 905 Titrando main unit + 800 Dosino burette piston actuator + Dosing Unit 20mL burette + 814 USB sample processor 814 autosampler can be used for fully automated testing of acid and alkalinity values ​​of lubricating oil products. Existing potentiometric titrators use a screw-driven piston for titration, achieving a liquid addition resolution of 0.01% or even 0.1% per hundred thousand. The burette in existing potentiometric titrators is protected by an outer shell, with the gap between the protective shell and the piston rod reaching the micrometer level. An outermost protective shell is also present, connecting the bottom to the dispenser. A small drying tube containing soda lime is installed at the connection point to remove carbon dioxide from the air. However, during the titration process, because the acid value test uses the toxic chemical reagent toluene, the test must be conducted in a fume hood where air is flowing. The small drying tube provided by the manufacturer cannot completely absorb the carbon dioxide in the air. The screw of the drive unit drives the piston downwards during titration, and the titrant in the burette gradually decreases. More and more of the upper part of the burette comes into contact with air. The trace amounts of potassium hydroxide isopropanol solution remaining inside the glass burette react chemically with the carbon dioxide in the air to produce potassium carbonate powder. Potassium carbonate powder is poorly soluble in potassium hydroxide isopropanol solution. Over time, the amount of potassium carbonate powder inside and at the top of the glass burette gradually increases. The presence of potassium carbonate at the top is due to the sealed contact between the piston and the glass burette; as the piston moves upwards, it scrapes out most of the potassium carbonate powder. The presence of potassium carbonate powder can easily cause wear and tear on the inside of the glass burette and the piston, even leading to damage and leakage.

[0003] The above background information is provided only to aid in understanding the concept and technical solution of this utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Utility Model Content

[0004] The main purpose of this utility model is to propose a burette protective cover for an automatic potentiometric titrator, so as to solve the problem that the aforementioned background technology lacks the function of removing carbon dioxide.

[0005] Therefore, this utility model proposes a burette protective cover for an automatic potentiometric titrator.

[0006] Preferably, the present invention may also have the following technical features:

[0007] A protective cover for the burette of an automatic potentiometric titrator includes a cover body, which is a cylindrical structure with both ends through it, and has an annular belt of soda lime inside.

[0008] Furthermore, the soda lime annular belt is provided with an upper baffle, a lower baffle, and an inner baffle, which together with the inner side of the cylinder of the cover form a space for holding soda lime.

[0009] Furthermore, the upper and lower baffles are perforated plates, and degreased cotton is laid on the side of the upper and lower baffles facing the accommodating space.

[0010] Furthermore, the inner baffle is a perforated plate, and degreased cotton is laid on the side facing the accommodating space.

[0011] Furthermore, the quicklime is sodium lime granules.

[0012] Furthermore, when the cover abuts against the predetermined position of the titrator reagent bottle, the soda lime annular band is positioned above the VENT port of the titrator.

[0013] Furthermore, the lower end of the cover is provided with a sealant, which is located at the position where the cover contacts the reagent bottle of the titrator, and / or the sealant is provided on the inner side of the soda lime annular strip.

[0014] Furthermore, the sealant is an elastic air cushion.

[0015] Furthermore, the sealant can also be a felt layer.

[0016] Furthermore, the upper opening of the cover is provided with a tapering structure.

[0017] The beneficial effects of this invention compared with the prior art include: by isolating the airflow of the external environment of the burette through the cover, the carbon dioxide inside the protective cover can be adsorbed by the soda lime placed in the soda lime placement area, and the burette of the automatic potentiometric titrator is tested in a carbon dioxide-free environment. This effectively prevents the trace amount of potassium hydroxide isopropanol solution remaining in the upper part of the glass burette from coming into contact with carbon dioxide in the air and reacting chemically when the piston in the glass burette moves downward during the titration test. Attached Figure Description

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

[0019] Figure 2This is a top view of the present invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0021] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0022] like Figure 1-2The illustration shows a protective cover for the burette of an automatic potentiometric titrator, comprising a cover body 3, which is a cylindrical structure extending through both ends, with an annular belt of soda lime 12 inside. Preferably, the annular belt of soda lime 12 has an upper baffle 32, a lower baffle 34, and an inner baffle 33. The upper baffle, lower baffle, and inner baffle are annular plate structures, and the three together, together with the inner side of the cover body 3, form a space for holding soda lime, and a number of soda lime particles 4 are placed in the space. Optionally, the soda lime is sodium lime, and the sodium lime is columnar particles. In use, the lower end of the cover body 3 is brought into contact with the upper circumference of the reagent bottle 1 of the titrator, and the annular belt of soda lime 12 surrounds the outer shell 2 of the titrator in the middle, maintaining a small gap between the two shells to reduce the passage of air through the gap between the outer shell 2 and the annular belt of soda lime 12. Thus, due to the good sealing effect achieved by the lower end of the cover 3 fitting snugly against the reagent bottle 1 of the titrator, a cavity is formed between the soda lime annular belt 12, the outer shell 2 of the titrator, and the reagent bottle 1. When air enters the cavity from the upper end of the cover 3 downwards, it passes through the soda lime annular belt 12, thereby absorbing the carbon dioxide in the air passing through the soda lime annular belt 12, significantly reducing the amount of powder generated by the reaction of carbon dioxide and titrant. Using granular soda lime as an isolation belt can reduce the resistance to air passage. The lower part of the outer shell 2 of the titrator has multiple VENT ports 8, typically four, for connecting the burette 9. Generally, air enters the interior of the outer shell 2 through the upper and lower gaps of the VENT ports 8 and comes into contact with the titrant. Therefore, to reduce powder generation, when the cover 3 abuts against the predetermined position of the reagent bottle 1 of the titrator, the soda lime annular belt 12 is positioned above the VENT ports 8 and above the upper gap of the VENT ports 8. Furthermore, the upper baffle 32 and lower baffle 34 are perforated plates, and degreased cotton is laid on the side of the upper baffle 32 and lower baffle 34 facing the receiving space. Preferably, the inner baffle 33 is a perforated plate, and degreased cotton is also provided on the side facing the receiving space. To facilitate the loading and unloading of soda lime, the inner baffle 33 is fixed to one end of the lower baffle 34, and the other end of the lower baffle 34 is fixed to the inner side of the cylinder of the cover 3. In this way, the inner baffle 33, the lower baffle 34 and the cover form an annular groove with an open top for placing soda lime. After the soda lime is placed, the upper baffle 32 is placed on the annular groove.

[0023] In a preferred embodiment, a perforation is provided at the lower part of the housing 3, corresponding to the VENT port 8. The burette 9 passes through the perforation and connects to the VENT port 8. Generally, the titrator has multiple VENT ports 8, but during operation, only one VENT port 8 is typically used, and the others are sealed to prevent air from entering the titrator's housing through the VENT ports 8. Preferably, to improve airtightness, a removable sealing ring 13 is installed at the junction of the burette and the VENT port 8.

[0024] In other embodiments, the lower end of the cover 3 is provided with a sealant 5, which is located at the contact point between the cover 3 and the titrator reagent bottle 1 to improve the sealing performance of the connection between the cover 3 and the titrator reagent bottle 1. Preferably, the sealant is provided on the inner side of the soda lime annular belt 12 to improve the sealing performance of the mating surface between the soda lime annular belt 12 and the titrator housing 2.

[0025] In the above, the sealing material 5 is an elastic air cushion, which facilitates full contact between the air cushion and the outside of the reagent bottle 1, making adjustment easier; on the other hand, it also facilitates reducing the resistance of the cover 3 when it is installed on the titrator through deformation.

[0026] In other options, the sealant 5 can also be a felt layer. Felt layers are simple to arrange and have good wear resistance.

[0027] In the above embodiments, the upper opening of the cover 3 is provided with a tapering structure. The tapering structure includes a limiting plate 31, and the limiting plate 31 has a central hole in its middle, the diameter of which is larger than the outer diameter of the titrator housing 2. By setting the tapering structure to reduce the gap between the titrator housing 2 and the cover 3, the swing amplitude of the cover 3 can be reduced, thereby stabilizing the cover 3 when mounted on the titrator.

[0028] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0029] Although exemplary embodiments of the present invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the present invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the present invention.

Claims

1. A burette protective cover for an automatic potentiometric titrator, characterized in that: Includes a cover, which is a cylindrical structure with two through ends, and has an annular belt of soda lime inside; The soda lime annular belt is provided with an upper baffle, a lower baffle, and an inner baffle. The upper baffle, the lower baffle, the inner baffle, and the inner side of the cylinder of the cover form a space for holding soda lime. The upper and lower baffles are perforated plates, and degreased cotton is laid on the side of the upper and lower baffles facing the accommodating space; The inner baffle is a perforated plate, and degreased cotton is laid on the side facing the accommodating space.

2. The burette protective cover of the automatic potentiometric titrator as described in claim 1, characterized in that: The quicklime is sodium lime granules.

3. The burette protective cover of the automatic potentiometric titrator as described in claim 1, characterized in that: When the cover is brought into contact with the reagent bottle of the titrator at the predetermined position, the soda lime ring is located above the VENT port of the titrator.

4. The burette protective cover of the automatic potentiometric titrator as described in claim 1, characterized in that: The lower end of the cover is provided with a sealant, which is located at the position where the cover contacts the reagent bottle of the titrator, and / or the sealant is provided on the inner side of the soda lime annular strip.

5. The burette protective cover of the automatic potentiometric titrator as described in claim 4, characterized in that: The sealant is an elastic air cushion.

6. The burette protective cover of the automatic potentiometric titrator as described in claim 4, characterized in that: The sealing material is a layer of felt.

7. The burette protective cover of the automatic potentiometric titrator as described in claim 1, characterized in that: The upper opening of the cover is provided with a tapering structure.

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