A freezing point measuring instrument for preparing acrylonitrile inhibitor

Abstract

The present invention belongs to the technical field of liquid freezing point detection equipment, and in particular, relates to a freezing point measuring instrument for preparing acrylonitrile inhibitor, comprising a detector body, a refrigeration box is arranged inside the detector body, two cold trap tubes are symmetrically plugged into the top of the refrigeration box, and the cold trap tubes are inserted through the top of the detector body, and observation ports are symmetrically opened on both sides of the detector body and both sides of the cold trap tubes, and transparent glass sheets are installed in the observation ports. The present invention is provided with a protective component, and before pouring the oil into the inner test tube, the bottom end of the inner test tube is first plugged into the inner side of the support ring, the support ring and the retaining ring in sequence, and then the inner test tube containing the oil is inserted into the outer test tube. In this process, due to the protective effect of the support ring, the support ring, the retaining ring and the protective strip, the outer side of the inner test tube will not collide with the tube mouth or inner wall of the outer test tube, thereby avoiding the outer test tube and the inner test tube from being damaged due to the collision.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid solidification point detection equipment, and in particular relates to a solidification point measuring instrument for preparing acrylonitrile polymerization inhibitor. Background Art

[0002] The freezing point is the highest temperature of the oil product when the sample oil is placed in a test tube and cooled to the point where the liquid surface does not move under the specified test conditions. The freezing point is an indicator for evaluating the low-temperature performance of oil products, and it is also an indicator that must be mastered when storing, transporting, receiving and sending oil products. The freezing point of existing oil products is generally measured using a freezing point tester. During the test, the oil product needs to be added to the inner test tube and the liquid surface is flush with the scale line on the inner test tube. Then, about 1 ml of anhydrous ethanol is added to the outer test tube. Then, the inner test tube containing the oil product is inserted into the outer test tube. Then, the detection rod on the detection probe is inserted into the inner test tube and locked. Then, the outer test tube is inserted into the cold trap of the detector for automatic detection.

[0003] In the above-mentioned testing process, since both the inner test tube and the outer test tube are made of transparent glass, when the inner test tube is inserted into or pulled out of the outer test tube, the inner test tube will inevitably collide with the inner wall or the tube mouth of the outer test tube. Especially after low-temperature freezing, both the outer test tube and the inner test tube become brittle, so the collision between the two makes it easier for the outer test tube or the inner test tube to break. Summary of the invention

[0004] In view of the above problems, the present invention provides a freezing point measuring instrument for preparing acrylonitrile inhibitor to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor comprises a detector body, a refrigeration box is arranged on the inner side of the detector body, two cold trap tubes are symmetrically inserted on the top of the refrigeration box, the cold trap tubes are inserted through the top of the detector body, observation ports are symmetrically opened on both sides of the detector body and both sides of the cold trap tubes, transparent glass sheets are installed in the observation ports, an outer test tube is inserted in the cold trap tube, an inner test tube is inserted on the inner side of the outer test tube, a limit ring is arranged near the top of the inner test tube, and the outer diameter of the limit ring matches the inner diameter of the outer test tube, a scale line is arranged on the surface of the lower half of the inner test tube, a protective component is sleeved on the outer side of the inner test tube, a detection probe is arranged on the top of the outer test tube, and the A data cable is connected between the detection probe and the detector body, a fixed sleeve is slidably sleeved on the outer side of the detection probe, a rubber sleeve is fixedly sleeved at the position opposite to the fixed sleeve of the outer test tube, locking screws are threadedly penetrated and inserted at the positions opposite to the rubber sleeve on both sides of the fixed sleeve, a plurality of first telescopic rods are annularly distributed on the top of the fixed sleeve, the first telescopic rods are vertically fixedly connected to the top of the fixed sleeve, a same fixing ring is fixedly connected to the top of the plurality of first telescopic rods, the fixing ring is fixedly sleeved at a position near the top of the detection probe, a supporting spring is sleeved on the first telescopic rod, and the two ends of the supporting spring are respectively fixedly connected to the fixing ring and the fixing sleeve, and a detection rod is vertically and rotatably connected to the bottom axis of the detection probe.

[0007] Furthermore, the protective component includes a support ring, the bottom of the support ring symmetrically supports two positioning blocks, the positioning blocks are fixedly connected to the inner wall of the outer test tube, the support ring is slidably sleeved on the outside of the inner test tube, the bottom of the support ring is sequentially provided with a supporting ring and a retaining ring from top to bottom, the supporting ring and the retaining ring are both slidably sleeved on the inner test tube, the outer top edge of the retaining ring is made of soft rubber material, and the outer side of the retaining ring fits the inner wall of the outer test tube, the top of the support ring is symmetrically and vertically fixedly connected with two pull rods, the top of the pull rods is slidably sleeved with a sleeve The sleeve is vertically fixedly connected to the bottom of the support ring, a first return spring is fixedly connected between the top of the pull rod and the top inner wall of the sleeve, a second telescopic rod is vertically fixedly connected between the top of the baffle ring and the bottom of the support ring, a rubber ring is fixedly connected to the inner side of the baffle ring, and the inner side of the rubber ring is tightly attached to the surface of the inner test tube, a positioning ring is supported by the bottom edge of the baffle ring, and notches are provided at the positions of the side faces of the baffle ring opposite to the two positioning blocks, and the width of the notch is greater than the width of the positioning blocks, and a U-shaped protective strip is fixedly connected to the bottom of the baffle ring.

[0008] Furthermore, an annular groove is provided at the center of the bottom circle of the detection probe, and a movable plate matching the area size of the groove is provided in the groove, and the movable plate is movably sleeved on the detection rod, and a slider is fixedly connected to the side of the movable plate, and a vertical slide groove is provided at the position where the side wall of the groove is opposite to the slider, and the slider is slidably installed in the corresponding slide groove, and a second return spring is fixedly connected between the top of the slider and the top groove wall of the slide groove, and in an initial state, the slider and the movable plate can be flush with the bottom of the detection probe under the pressing action of the second return spring, and the bottom of the slider is vertically fixedly connected to a pressure rod, and the bottom ends of multiple pressure rods are fixedly connected to the same pressure ring, and the pressure ring is opposite to the tube mouth of the inner test tube, and two guide rods are horizontally fixedly connected to the inner side of the movable plate, and a spiral guide groove is provided at the position where the side of the detection rod is opposite to the guide rod, and the two guide grooves are rotationally symmetrical about the axis of the detection rod, and the two guide rods are respectively inserted in the two guide grooves.

[0009] Furthermore, the protective strip is made of elastic plastic material, and when the second telescopic rod is in a fully extended state, the bottom of the protective strip fits against the bottom inner wall of the outer test tube, and at this time the distance from the bottom of the protective strip to the bottom of the inner test tube is equal to the maximum contraction amount of the second telescopic rod and the first return spring.

[0010] Furthermore, an annular rubber pad is installed at the bottom of the pressure ring, and the size of the rubber pad matches the size of the tube opening of the inner test tube.

[0011] Furthermore, the scale lines on the side wall of the inner test tube are opposite to the cold trap tube and the observation port on the side of the detector body, and when the protective assembly is sleeved on the inner test tube, the retaining ring is opposite to the scale lines.

[0012] Furthermore, the sum of the elastic forces of the two first return springs is always greater than the sum of the elastic forces of the plurality of second return springs, and the maximum compression of the first return spring is equal to the maximum compression of the first telescopic rod and the support spring.

[0013] Furthermore, the support ring, the supporting ring and the retaining ring are all made of plastic, and the outer diameters of the support ring and the supporting ring are smaller than the inner diameter of the outer test tube.

[0014] Furthermore, the pull rod, the sleeve, the second telescopic rod and the protective strip are all located in the same vertical plane, and the vertical plane where the two notches are located is perpendicular to the above-mentioned vertical plane.

[0015] Technical effects and advantages of the present invention:

[0016] 1. The present invention is provided with a protective assembly. Before pouring the oil into the inner test tube, the bottom end of the inner test tube is first inserted into the inner side of the support ring, the support ring and the retaining ring in sequence, and then the inner test tube filled with the oil is inserted into the outer test tube. In this process, due to the protective effect of the support ring, the support ring, the retaining ring and the protective strip, the outer side of the inner test tube will not collide with the tube mouth or the inner wall of the outer test tube, thereby avoiding the outer test tube and the inner test tube from being damaged due to collision;

[0017] 2. The present invention is provided with a retaining ring. When frost appears on the outer wall of the inner test tube and the inner wall of the outer test tube, the detection probe can be pressed to drive the inner test tube to move downward, and then the rubber ring located on the inner side of the retaining ring can scrape the outer wall of the inner test tube, so that the frost condensed above the scale line on the outer wall of the inner test tube can be scraped off by the rubber ring. Then, when the inner test tube is reset upward, the outer side of the retaining ring can scrape off the part of the inner wall of the outer test tube located above the scale line, so that the detection personnel can clearly observe the liquid level of the oil product inside the inner test tube through the scraped parts of the outer test tube and the inner test tube, thereby improving the accuracy and convenience of oil product detection;

[0018] 3. The present invention is provided with a guide rod. After the detection of the oil product is completed, as the detection probe moves upward, the guide rod on the inner side of the movable plate can move reversely along the guide groove, so that the detection rod can rotate reversely through the pushing action of the guide rod on the guide groove. As the detection rod rotates reversely, the part of the detection rod frozen by the oil product can be better separated from the frozen oil product, thereby preventing the oil product frozen on the detection rod from being taken out when the detection rod is pulled out of the inner test tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 It is a three-dimensional schematic diagram of the detector body and its internal structure in the present invention;

[0021] Figure 3 It is a three-dimensional schematic diagram of the structures of the present invention, such as the outer test tube, the monitoring probe, the fixing sleeve, the first telescopic rod and the supporting spring;

[0022] Figure 4 It is a three-dimensional cross-sectional view of the structures of the inner and outer test tubes, the monitoring probe and the fixing sleeve in the present invention;

[0023] Figure 5 The present invention Figure 4 A magnified view of part A;

[0024] Figure 6 is a three-dimensional cross-sectional view of the outer test tube of the present invention;

[0025] Figure 7is a three-dimensional schematic diagram of the protection component in the present invention;

[0026] Figure 8 It is a schematic diagram of a partial three-dimensional structure of the detection rod in the present invention;

[0027] Fig. 9 It is a three-dimensional schematic diagram of the movable plate, the slider, the second return spring, the pressure rod, the pressure ring and the guide rod in the present invention;

[0028] Fig.10 It is a three-dimensional schematic diagram of the inner test tube in the present invention.

[0029] In the figure: 1. detector body; 2. refrigeration box; 3. cold trap tube; 4. observation port; 5. outer test tube; 6. inner test tube; 7. limit ring; 8. scale line; 9. protection assembly; 901. support ring; 902. positioning block; 903. support ring; 904. retaining ring; 905. pull rod; 906. sleeve; 907. first return spring; 908. second telescopic rod; 909. rubber ring; 910. positioning ring; 911. notch; 912. protection strip; 10. detection probe; 11. data cable; 12. fixing sleeve; 13. rubber sleeve; 14. locking screw; 15. first telescopic rod; 16. fixing ring; 17. support spring; 18. detection rod; 19. movable plate; 20. slider; 21. second return spring; 22. pressure rod; 23. pressure ring; 24. guide rod; 25. guide groove; 26. rubber pad. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0031] The present invention provides Figures 1 to 10The freezing point measuring instrument for preparing acrylonitrile inhibitor shown in the figure comprises a detector body 1, a refrigeration box 2 is arranged on the inner side of the detector body 1, two cold trap tubes 3 are symmetrically inserted on the top of the refrigeration box 2, and the cold trap tubes 3 are inserted through the top of the detector body 1, observation ports 4 are symmetrically opened on both sides of the detector body 1 and both sides of the cold trap tubes 3, and transparent glass sheets are installed in the observation ports 4, an outer test tube 5 is inserted in the cold trap tube 3, an inner test tube 6 is inserted on the inner side of the outer test tube 5, a limiting ring 7 is arranged near the top of the inner test tube 6, and the outer diameter of the limiting ring 7 matches the inner diameter of the outer test tube 5, a scale line 8 is arranged on the surface of the lower half of the inner test tube 6, a protective component 9 is sleeved on the outer side of the inner test tube 6, a detection probe 10 is arranged on the top of the outer test tube 5, and the detection probe 10 is connected to the detector body 1 is connected with a data line 11, a fixed sleeve 12 is slidably sleeved on the outer side of the detection probe 10, a rubber sleeve 13 is connected to the fixed sleeve 12 at a position opposite to the outer test tube 5 and the fixed sleeve 12, and locking screws 14 are threadedly penetrated and inserted at positions opposite to the rubber sleeve 13 on both sides of the fixed sleeve 12, and a plurality of first telescopic rods 15 are annularly distributed on the top of the fixed sleeve 12, and the first telescopic rods 15 are vertically fixedly connected to the top of the fixed sleeve 12, and the tops of the plurality of first telescopic rods 15 are fixedly connected with the same fixing ring 16, and the fixing sleeve 12 of the fixing ring 16 is connected to a position of the detection probe 10 near the top, and a support spring 17 is sleeved on the first telescopic rod 15, and the two ends of the support spring 17 are respectively fixedly connected to the fixing ring 16 and the fixing sleeve 12, and a detection rod 18 is vertically rotatably connected to the bottom axis of the detection probe 10;

[0032] Before pouring the oil into the inner test tube 6, the protective component 9 is first sleeved on the outer side of the inner test tube 6 to protect the inner test tube 6, and then the oil to be tested is injected into the inner test tube 6, and the liquid level of the oil is flush with the scale line 8, and then the inner test tube 6 filled with the oil is inserted into the outer test tube 5. In this process, due to the protective effect of the protective component 9, the outer side of the inner test tube 6 will not collide with the tube mouth or inner wall of the outer test tube 5, thereby avoiding the outer test tube 5 and the inner test tube 6 from being damaged due to collision. After being inserted into the outer test tube 5, the detection rod 18 is inserted into the inner test tube 6. When the detection probe 10 contacts the top edge of the inner test tube 6, the locking screws 14 on both sides of the fixed sleeve 12 are also opposite to the rubber sleeve 13 of the outer test tube 5. Then, the two locking screws 14 are tightened in turn, so that the locking operation of the outer test tube 5 and the detection probe 10 is realized through the squeezing effect of the locking screws 14 on the rubber sleeve 13. Finally, the outer test tube 5 is inserted into the cold trap tube 3 and the detector body 1 is started to perform a freezing point test on the oil in the inner test tube 6.

[0033] like Figures 4 to 7As shown, the protection component 9 includes a support ring 901, the bottom of the support ring 901 symmetrically supports two positioning blocks 902, the positioning blocks 902 are fixedly connected to the inner wall of the outer test tube 5, the support ring 901 is slidably sleeved on the outside of the inner test tube 6, and the bottom of the support ring 901 is sequentially provided with a supporting ring 903 and a retaining ring 904 from top to bottom, the supporting ring 903 and the retaining ring 904 are both slidably sleeved on the inner test tube 6, the outer top edge of the retaining ring 904 is made of soft rubber, and the outer side of the retaining ring 904 is in contact with the inner wall of the outer test tube 5, and the top of the support ring 903 is against the inner wall of the outer test tube 5. There are two pull rods 905 vertically fixedly connected, and the top of the pull rod 905 is slidably sleeved with a sleeve 906, and the sleeve 906 is vertically fixedly connected to the bottom of the support ring 901. A first return spring 907 is fixedly connected between the top of the pull rod 905 and the top inner wall of the sleeve 906. A second telescopic rod 908 is vertically fixedly connected between the top of the retaining ring 904 and the bottom of the supporting ring 903. A rubber ring 909 is fixedly connected to the inner side of the retaining ring 904, and the inner side of the rubber ring 909 is tightly attached to the surface of the inner test tube 6. The bottom edge of the retaining ring 904 is supported by a positioning ring 910, the side of the retaining ring 904 opposite to the two positioning blocks 902 is provided with a notch 911, and the width of the notch 911 is greater than the width of the positioning block 902, and the bottom of the retaining ring 904 is fixedly connected with a U-shaped protective strip 912, and the protective strip 912 is made of elastic plastic material, and when the second telescopic rod 908 is in a fully extended state, the bottom of the protective strip 912 fits the bottom inner wall of the outer test tube 5, and at this time, the distance from the bottom of the protective strip 912 to the bottom of the inner test tube 6 is equal to the maximum contraction of the second telescopic rod 908 and the first reset spring 907, so The scale line 8 on the side wall of the inner test tube 6 is opposite to the cold trap tube 3 and the observation port 4 on the side of the detector body 1, and when the protective component 9 is sleeved on the inner test tube 6, the retaining ring 904 is opposite to the scale line 8, the pull rod 905, the sleeve 906, the second telescopic rod 908 and the protective strip 912 are all located in the same vertical plane, and the vertical plane where the two notches 911 are located is perpendicular to the vertical plane mentioned above, the support ring 901, the support ring 903 and the retaining ring 904 are all made of plastic, and the outer diameters of the support ring 901 and the support ring 903 are smaller than the inner diameter of the outer test tube 5;

[0034] Before pouring the oil into the inner test tube 6, the bottom end of the inner test tube 6 is inserted into the inner sides of the support ring 901, the support ring 903 and the baffle ring 904 in sequence, and since the inner side of the baffle ring 904 is provided with a rubber ring 909, when the baffle ring 904 is sleeved onto the outer side of the inner test tube 6 and is flush with the position of the scale line 8, the baffle ring 904 can be fixed at the scale line 8 of the inner test tube 6 through the rubber ring 909, and the support ring 901, the support ring 903, the baffle ring 904 and the protective strip 91 2 can protect the outer periphery of the inner test tube 6, then inject the oil product to be tested into the inner test tube 6, and make the liquid level of the oil product flush with the scale line 8, and then insert the inner test tube 6 filled with the oil product into the outer test tube 5. In this process, due to the protective effect of the support ring 901, the support ring 903, the retaining ring 904 and the protective strip 912, the outer side of the inner test tube 6 will not collide with the tube mouth or the inner wall of the outer test tube 5, thereby avoiding the outer test tube 5 and the inner test tube 6 from being damaged due to collision;

[0035] In addition, when the inner test tube 6 is inserted into the outer test tube 5, the two notches 911 on the retaining ring 904 are opposite to the two positioning blocks 902 on the inner wall of the outer test tube 5, so that when the retaining ring 904 moves downward to a position opposite to the positioning blocks 902, the positioning blocks 902 can pass through the notches 911, and thus will not hinder the downward movement of the retaining ring 904. As the inner test tube 6 continues to be inserted, when the bottom of the supporting ring 903 contacts the positioning blocks 902, the bottom of the retaining ring 904 also happens to contact the positioning ring 910. At this time The outer test tube 5 stops moving downward, and the second telescopic rod 908 is also in a fully extended state. Then, the detection rod 18 is inserted into the inner test tube 6, and the detection probe 10 and the outer test tube 5 are locked together by two locking screws 14. Finally, the outer test tube 5 is inserted into the cold trap tube 3. When inserting, the outer test tube 5 is adjusted so that the two notches 911 are respectively opposite to the observation ports 4 on both sides of the cold trap tube 3, so that the oil in the inner test tube 6 will not be blocked by the pull rod 905, the sleeve 906, the second telescopic rod 908 and the protective strip 912.

[0036] During the process of the detector body 1 detecting the oil product, in order to reduce the temperature of the coolant and prevent the oil product from cooling too quickly, thereby affecting the accurate determination of the freezing point, anhydrous ethanol is added to the outer test tube 5. However, due to the presence of anhydrous ethanol, frost will appear on the inner wall of the outer test tube 5 and the outer wall of the inner test tube 6 during the detection process, thereby affecting the observation effect of the oil product liquid level. At this time, the detection probe 10 is pressed to squeeze the inner test tube 6 downward, and as the detection probe 10 moves downward, the support spring 17 and the first telescopic rod 15 The inner tube 6 is gradually compressed. At the same time, as the inner tube 6 moves downward, the inner tube 6 can squeeze the support ring 901 downward through the limit ring 7, so that the support ring 901 can move downward and compress the first return spring 907. On the other hand, as the inner tube 6 moves downward, since the retaining ring 904 is restricted by the positioning ring 910, the rubber ring 909 located on the inner side of the retaining ring 904 can scrape the outer wall of the inner tube 6 upward from the position of the scale line 8 of the inner tube 6, so that the condensation on the inner tube 6 The frost on the outer wall of the test tube 6 above the scale line 8 can be scraped off by the rubber ring 909, and when the pressure on the detection probe 10 stops, the rubber ring 909 can fix the retaining ring 904 in the moved position. Subsequently, as the detection probe 10 is released, the support spring 17 can push the fixing ring 16 upward to drive the detection probe 10 to move upward. At the same time, the first return spring 907 can push the support ring 901 upward, so that the inner test tube 6 can move upward under the thrust of the support ring 901 on the limit ring 7. As the inner test tube 6 moves upward, , the inner test tube 6 can pull the retaining ring 904 to move upward, and in the process of the retaining ring 904 moving upward, the soft rubber part of the outer top edge of the retaining ring 904 can move upward along the inner wall of the outer test tube 5, thereby scraping the part of the inner wall of the outer test tube 5 above the scale line 8. During this process, the second telescopic rod 908 is gradually shortened. When the inner test tube 6 is reset, the inspection personnel can clearly observe the liquid level of the oil inside the inner test tube 6 through the scraped parts of the outer test tube 5 and the inner test tube 6, thereby improving the accuracy and convenience of oil inspection.

[0037] like Figures 4 to 9As shown, an annular groove is provided at the center of the bottom circle of the detection probe 10, and a movable plate 19 matching the area of ​​the groove is provided in the groove, and the movable plate 19 is movably sleeved on the detection rod 18, and a slider 20 is fixedly connected to the side of the movable plate 19, and a vertical slide groove is provided at a position opposite to the side wall of the groove and the slider 20, and the slider 20 is slidably installed in the corresponding slide groove, and a second return spring 21 is fixedly connected between the top of the slider 20 and the top groove wall of the slide groove, and in the initial state, the slider 20 and the movable plate 19 can be flush with the bottom of the detection probe 10 under the pressing action of the second return spring 21, and the bottom of the slider 20 is vertically fixedly connected to a pressure rod 22, and the bottom ends of the plurality of pressure rods 22 are fixedly connected There is a same pressing ring 23, the pressing ring 23 is opposite to the tube mouth of the inner test tube 6, two guide rods 24 are horizontally fixedly connected to the inner side of the movable plate 19, a spiral guide groove 25 is opened at the position opposite to the guide rod 24 on the side of the detection rod 18, and the two guide grooves 25 are rotationally symmetrical about the axis of the detection rod 18, and the two guide rods 24 are respectively inserted in the two guide grooves 25, and an annular rubber pad 26 is installed at the bottom of the pressing ring 23, and the size of the rubber pad 26 matches the size of the tube mouth of the inner test tube 6, the sum of the elastic forces of the two first reset springs 907 is always greater than the sum of the elastic forces of the multiple second reset springs 21, and the maximum compression of the first reset spring 907 is equal to the maximum compression of the first telescopic rod 15 and the support spring 17;

[0038] By providing the movable plate 19, in the process of inserting the detection rod 18 at the bottom of the detection probe 10 into the inner test tube 6, as the detection rod 18 is gradually inserted into the inner test tube 6, the pressure ring 23 at the bottom of the detection probe 10 can gradually approach the tube mouth of the inner test tube 6. When the rubber pad 26 at the bottom of the pressure ring 23 contacts the tube mouth of the inner test tube 6, as the detection probe 10 continues to move downward, since the sum of the elastic forces of the two first return springs 907 is always greater than the sum of the elastic forces of the plurality of second return springs 21, the movable plate 19 can slide against the pressure rod 22. The movable plate 19 moves upward under the pushing action of the block 20, and as the slider 20 moves upward along the slide groove, the second return spring 21 can be gradually compressed. At the same time, as the movable plate 19 moves upward, the guide rod 24 on the inner side of the movable plate 19 can move along the guide groove 25, so that the detection rod 18 can rotate through the toggling action of the guide rod 24 on the guide groove 25. When the detection probe 10 is pressed tightly together with the top edge of the outer test tube 5, the two locking screws 14 are screwed in turn to lock the fixing sleeve 12 and the detection probe 10.

[0039] When the oil test is completed, as the two locking screws 14 are loosened, the detection probe 10 can be pushed upward by the second return spring 21, and the movable plate 19 gradually moves downward. At the same time, as the movable plate 19 moves downward, the guide rod 24 on the inner side of the movable plate 19 can move in the opposite direction along the guide groove 25, so that the detection rod 18 can rotate in the opposite direction through the pushing action of the guide rod 24 on the guide groove 25. As the detection rod 18 rotates in the opposite direction, the part of the detection rod 18 frozen by the oil can be better separated from the frozen oil, so as to avoid the oil frozen on the detection rod 18 being taken out when the detection rod 18 is pulled out of the inner test tube 6.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor, comprising a detector body (1), characterized in that: A refrigeration box (2) is arranged on the inner side of the detector body (1), and two cold trap tubes (3) are symmetrically inserted on the top of the refrigeration box (2). The cold trap tubes (3) are inserted through the top of the detector body (1). Observation ports (4) are symmetrically provided on both sides of the detector body (1) and both sides of the cold trap tubes (3), and transparent glass sheets are installed in the observation ports (4). An external test tube (5) is inserted in the cold trap tube (3), and the external test tube (5) is An inner test tube (6) is inserted inside, a limit ring (7) is arranged near the top of the inner test tube (6), and the outer diameter of the limit ring (7) matches the inner diameter of the outer test tube (5), a scale line (8) is arranged on the surface of the lower half of the inner test tube (6), a protective component (9) is sleeved on the outer side of the inner test tube (6), a detection probe (10) is arranged on the top of the outer test tube (5), and a data line (10) is connected between the detection probe (10) and the detector body (1). 1), a fixed sleeve (12) is slidably sleeved on the outer side of the detection probe (10), a rubber sleeve (13) is fixedly sleeved at a position opposite to the fixed sleeve (12) of the outer test tube (5), locking screws (14) are threadedly inserted through the positions opposite to the rubber sleeve (13) on both sides of the fixed sleeve (12), a plurality of first telescopic rods (15) are annularly distributed on the top of the fixed sleeve (12), the first telescopic rods (15) are vertically fixedly connected to the top of the fixed sleeve (12), the tops of the plurality of first telescopic rods (15) are fixedly connected to the same fixing ring (16), the fixing ring (16) is fixedly sleeved at a position close to the top of the detection probe (10), a supporting spring (17) is sleeved on the first telescopic rod (15), the two ends of the supporting spring (17) are respectively fixedly connected to the fixing ring (16) and the fixing sleeve (12), and a detection rod (18) is vertically rotatably connected to the bottom axis of the detection probe (10); The protective component (9) comprises a support ring (901), the bottom of the support ring (901) is symmetrically supported with two positioning blocks (902), the positioning blocks (902) are fixedly connected to the inner wall of the outer test tube (5), the support ring (901) is slidably sleeved on the outer side of the inner test tube (6), the bottom of the support ring (901) is provided with a supporting ring (903) and a retaining ring (904) in sequence from top to bottom, the supporting ring (903) and the retaining ring (904) are both slidably sleeved on the inner test tube (6), the outer top edge of the retaining ring (904) is made of soft rubber material, and the outer side of the retaining ring (904) is in contact with the inner wall of the outer test tube (5), the top of the support ring (903) is symmetrically and vertically fixedly connected with two pull rods (905), the top of the pull rod (905) is slidably sleeved with a sleeve (906), and the sleeve (9 06) is vertically fixedly connected to the bottom of the support ring (901), a first reset spring (907) is fixedly connected between the top of the pull rod (905) and the top inner wall of the sleeve (906), a second telescopic rod (908) is vertically fixedly connected between the top of the retaining ring (904) and the bottom of the supporting ring (903), a rubber ring (909) is fixedly connected to the inner side of the retaining ring (904), and the inner side of the rubber ring (909) is tightly attached to the surface of the inner test tube (6), the bottom edge of the retaining ring (904) is supported by a positioning ring (910), and the side of the retaining ring (904) is provided with a notch (911) at the position opposite to the two positioning blocks (902), and the width of the notch (911) is greater than the width of the positioning block (902), and the bottom of the retaining ring (904) is fixedly connected with a U-shaped protective strip (912).

2. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 1, characterized in that: The detection probe (10) is provided with an annular groove at the center of the bottom circle, and a movable plate (19) matching the area of ​​the groove is arranged in the groove, and the movable plate (19) is movably sleeved on the detection rod (18), and a slider (20) is fixedly connected to the side of the movable plate (19), and a vertical slide groove is provided at a position where the side wall of the groove is opposite to the slider (20), and the slider (20) is slidably installed in the corresponding slide groove, and a second return spring (21) is fixedly connected between the top of the slider (20) and the top groove wall of the slide groove, and in the initial state, the slider (20) and the movable plate (19) can be moved by the second return spring (21) ) is flush with the bottom of the detection probe (10) under the pressing action of the slider (20), the bottom of the slider (20) is vertically fixedly connected with a pressure rod (22), the bottom ends of multiple pressure rods (22) are fixedly connected with the same pressure ring (23), the pressure ring (23) is opposite to the tube mouth of the inner test tube (6), the inner side of the movable plate (19) is horizontally fixedly connected with two guide rods (24), the side of the detection rod (18) opposite to the guide rod (24) is provided with a spiral guide groove (25), and the two guide grooves (25) are rotationally symmetrical about the axis of the detection rod (18), and the two guide rods (24) are respectively inserted into the two guide grooves (25).

3. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 2, characterized in that: The protective strip (912) is made of elastic plastic material, and when the second telescopic rod (908) is in a fully extended state, the bottom of the protective strip (912) fits against the bottom inner wall of the outer test tube (5), and at this time, the distance from the bottom of the protective strip (912) to the bottom of the inner test tube (6) is equal to the maximum contraction amount of the second telescopic rod (908) and the first return spring (907).

4. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 3, characterized in that: An annular rubber pad (26) is installed at the bottom of the pressure ring (23), and the size of the rubber pad (26) matches the size of the tube mouth of the inner test tube (6).

5. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 4, characterized in that: The scale line (8) on the side wall of the inner test tube (6) is opposite to the cold trap tube (3) and the observation port (4) on the side of the detector body (1), and when the protective component (9) is sleeved on the inner test tube (6), the retaining ring (904) is opposite to the scale line (8).

6. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 2, characterized in that: The sum of the elastic forces of the two first return springs (907) is always greater than the sum of the elastic forces of the plurality of second return springs (21), and the maximum compression of the first return spring (907) is equal to the maximum compression of the first telescopic rod (15) and the support spring (17).

7. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 1, characterized in that: The support ring (901), the supporting ring (903) and the retaining ring (904) are all made of plastic, and the outer diameters of the support ring (901) and the supporting ring (903) are both smaller than the inner diameter of the outer test tube (5).

8. The freezing point measuring instrument for preparing acrylonitrile polymerization inhibitor according to claim 1, characterized in that: The pull rod (905), the sleeve (906), the second telescopic rod (908) and the protection strip (912) are all located in the same vertical plane, and the vertical plane where the two notches (911) are located is perpendicular to the above-mentioned vertical plane.

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