Experimental device for measuring atmospheric pressure

Abstract

The utility model belongs to the field of teaching experiments, and provides an experimental device for measuring atmospheric pressure, which comprises a cylinder body and a piston, the piston is arranged in the cylinder body in an air-tight seal manner, one end of the cylinder body is fixedly connected with a force-measuring tension spring connecting device, and a force-measuring tension spring is connected between the force-measuring tension spring connecting device and the piston; a vent hole is also formed in the end of the cylinder body; the other end of the cylinder body is fixedly connected with a manual switch valve, scale marks are arranged on the cylinder body between the piston and the manual switch valve, and an atmospheric pressure value and an atmospheric pressure value are correspondingly marked on the upper side and the lower side of the scale marks. When the device is used for an experiment, the manual switch valve is opened, the hose is connected with the air extractor, the air extractor is used for extracting air in the barrel body, and the manual switch valve is closed, so that the atmospheric pressure value and the corresponding atmospheric pressure can be directly read through the scale marks; according to the utility model, the force application object for force measurement is changed from human to atmosphere, students can intuitively understand the experiment process, static reading is adopted, the reading is accurate, and the experiment process is intuitive.

Description

Technical Field

[0001] The utility model belongs to the field of teaching experiments and relates to an experimental device for measuring atmospheric pressure. Background Art

[0002] Currently, in the teaching of physics courses, the experiment for measuring atmospheric pressure usually adopts the following several methods.

[0003] The first method is to measure the atmospheric pressure with a suction cup. The specific means are as follows: Press the suction cup onto the glass plate and exhaust the air in the suction cup as much as possible; Hang the dynamometer on the suction cup hook and use the spring dynamometer to vertically pull the suction cup upward. When the suction cup detaches from the glass plate, record the dynamometer reading. This reading is the pressure of the atmosphere on the suction cup; Measure the unfolded area of the suction cup to obtain the force-bearing area; Use the formula P = F / S to calculate the value of atmospheric pressure.

[0004] In this method, the pressure of the atmosphere on the suction cup is displayed by the reading of the dynamometer after being pulled by a person. The observable range of the experiment is small, and the atmospheric pressure is not directly displayed, resulting in poor intuitiveness; The force-applying object of the dynamometer is a person rather than the atmosphere, which brings confusion to students' understanding; It is difficult to exhaust all the air in the suction cup, and there are relatively large errors in the experiment.

[0005] The second method is the experiment for measuring atmospheric pressure with a syringe. The specific means are as follows: As shown in Figure 1 Draw in a small amount of water with the syringe, push the piston upward with the needle opening facing up to discharge the excess water, and block the injection hole with a stopper; Connect the hook of the dynamometer and the tail of the syringe piston with a thin line; Pull the piston with the dynamometer, and when the piston is pulled, read the dynamometer reading to obtain the atmospheric pressure; Measure the length of the graduated part of the syringe with a ruler, and calculate the cross-sectional area of the piston, which is the force-bearing area; Use the formula P = F / S to calculate the value of atmospheric pressure.

[0006] In this method, the experiment requires that "when the piston starts to move, record the dynamometer reading, which is the atmospheric pressure". However, in actual operation, if the piston is continuously pulled, the dynamometer reading will continue to increase within a certain range. Therefore, the dynamometer reading when the piston just starts to move often does not equal the atmospheric pressure; The force-bearing area of the syringe piston used is small, so the atmospheric pressure is also small, but the friction between the piston and the syringe barrel is relatively large. Therefore, the error is relatively large; The observable range of the experiment is small, and the atmospheric pressure is not directly displayed, resulting in poor intuitiveness; The pressure of the atmosphere on the piston is displayed by the reading of the dynamometer after being pulled by a person, but the force-applying object of the dynamometer is a person rather than the atmosphere, which brings confusion to students' understanding. Summary of the Invention

[0007] In order to overcome the deficiencies existing in the prior art, the present utility model proposes an experimental device for measuring atmospheric pressure. The force - applying object for measuring force changes from a human to the atmosphere, enabling students to intuitively understand the experimental process. Static readings are adopted, with accurate readings and an intuitive experimental process.

[0008] For this purpose, the technical solution of the present utility model is as follows: An experimental device for measuring atmospheric pressure, comprising a cylinder body and a piston. The piston is hermetically placed in the cylinder body, and is characterized in that:

[0009] At one end of the cylinder body, a force - measuring spring connecting device is fixedly connected. A force - measuring spring is connected between the force - measuring spring connecting device and the piston; and an air vent is also provided at this end of the cylinder body.

[0010] At the other end of the cylinder body, a manual switch valve is fixedly connected. Scale lines are provided on the cylinder body between the piston and the manual switch valve. The atmospheric pressure value and the atmospheric pressure intensity value are correspondingly marked on the upper and lower sides of the scale lines. The end face of the piston on the side of the manual switch valve corresponds to the zero scale position of the scale line, and the piston also serves as the scale pointer of the force - measuring spring.

[0011] Furthermore, the force - measuring spring connecting device includes a connecting seat, a pull rod, and an adjusting nut. One end of the connecting seat is provided with a threaded connection head. A guiding hole runs through the connecting seat. The pull rod passes through the guiding hole. The adjusting nut is threadedly connected to the tail end of the pull rod, and the adjusting nut contacts the end face of the connecting seat. The head of the pull rod is provided with a first connection hole. The connecting seat is threadedly connected to the cylinder body through the threaded connection head; with this structure, the force - measuring spring can be adjusted through the adjusting nut and the pull rod, driving the piston to be adjusted to the zero scale position of the scale line.

[0012] Furthermore, the piston includes a piston body and a sealing ring. The sealing ring is elastically sleeved on the head of the piston body. A second connection hole is provided at the tail of the piston body. The two ends of the force - measuring spring are respectively hooked on the first connection hole of the pull rod and the second connection hole of the piston body; this structural arrangement is simple and easy to implement.

[0013] Furthermore, the cylinder body is made of a transparent material, so that the movement process of the piston in the cylinder body and the telescopic process of the force - measuring spring can be visually observed, and the experimental process can be demonstrated more intuitively.

[0014] Furthermore, a sealing ring is provided between the manual switch valve and the cylinder body, and this setting can further ensure the air - tightness effect of the connection.

[0015] The beneficial effects of the present utility model are as follows: When using the present utility model for the experiment, open the manual switch valve, connect the air extractor with a hose, use the air extractor to extract the air in the cylinder body, and then close the manual switch valve. The atmospheric pressure value and the corresponding atmospheric pressure intensity can be directly read through the scale line; in the present utility model, the force - applying object for measuring force changes from a human to the atmosphere, enabling students to intuitively understand the experimental process. Static readings are adopted, with accurate readings and an intuitive experimental process. Description of the Drawings

[0016] Figure 1 is a schematic diagram of an experiment for measuring atmospheric pressure using a syringe in the prior art;

[0017] Figure 2 is a schematic structural diagram of the present utility model;

[0018] Figure 3 is a structural diagram of the force - measuring spring connection device in the present utility model.

[0019] As shown in the figure: 1. Force - measuring spring connection device; 101. Adjusting nut; 102. Connecting seat; 103. Pull rod; 2. Cylinder; 201. Vent hole; 202. Scale line; 3. Piston; 301. Piston body; 302. Sealing ring; 4. Manual switch valve; 401. External interface of the manual switch valve; 5. Sealing ring. Detailed Embodiment

[0020] Next, the present utility model will be further described in conjunction with the drawings and embodiments as follows.

[0021] As Figure 2 shown, an experimental device for measuring atmospheric pressure includes a cylinder 2 and a piston 3. The piston 3 is hermetically placed inside the cylinder 2. At one end of the cylinder 2, a force - measuring spring connection device 1 is fixedly connected. A force - measuring spring 6 is connected between the force - measuring spring connection device 1 and the piston 3. A vent hole 201 is also provided at this end of the cylinder. At the other end of the cylinder, a manual switch valve 4 is fixedly connected. The external interface 401 of the manual switch valve is used to connect to an external air extractor. Scale lines 202 are provided on the cylinder between the piston and the manual switch valve. The atmospheric pressure value and the atmospheric pressure intensity value are correspondingly marked on the upper and lower sides of the scale lines. F0 and F1 in the figure schematically represent the atmospheric pressure values, and P0 and P1 schematically represent the atmospheric pressure intensity values. The end face of the piston 3 on the side of the manual switch valve corresponds to the zero scale position of the scale line 202. The piston 3 also serves as the scale pointer of the force - measuring spring 6. A sealing ring 5 is provided between the manual switch valve 3 and the cylinder 2. This setting can further ensure the airtight effect of the connection.

[0022] As Figure 3 shown, a structure of the force - measuring spring connection device includes a connecting seat 102, a pull rod 103, and an adjusting nut 101. One end of the connecting seat is provided with a threaded connection head. A guiding hole runs through the connecting seat. The pull rod 103 passes through the guiding hole. The adjusting nut 101 is threadedly connected to the tail end of the pull rod 103. The adjusting nut 101 contacts the end face of the connecting seat 102. A first connection hole 1031 is provided at the head of the pull rod. The connecting seat 102 is threadedly connected to the cylinder through the threaded connection head.

[0023] As Figure 2 、 Figure 3As shown in the figure, the piston includes a piston body 301 and a sealing ring 302. The sealing ring 302 is elastically sleeved on the head of the piston body 301. A second connection hole 3011 is provided at the tail of the piston body. The two ends of the force-measuring tension spring are respectively hung on the first connection hole 1031 of the pull rod and the second connection hole 3011 of the piston body. At this time, the end face of the sealing ring 302 corresponds to the zero scale position of the scale line 202. This structural setting is simple and easy to implement.

[0024] The cylinder body is made of a transparent material, so that the movement process of the piston in the cylinder body and the telescopic process of the force-measuring tension spring can be visually observed, and the experimental process can be demonstrated more intuitively.

[0025] The working principle of the present utility model is as follows: Open the manual switch valve, connect the air extractor with a hose and maintain its airtightness. Use the air extractor to extract the air in the cylinder body, and then close the manual switch valve. The atmospheric pressure value and the corresponding atmospheric pressure value can be directly read through the scale line.

[0026] For the present utility model, simple combinations, equivalent replacements, and further improvements made without departing from the technical concept of the present utility model shall all be included within the protection scope of the present utility model.

Claims

1. An experimental device for measuring atmospheric pressure, comprising a cylinder and a piston, wherein the piston is placed in the cylinder in an airtight manner, and characterized in that: A force measuring tension spring connecting device is fixedly connected to one end of the cylinder, and a force measuring tension spring is connected between the force measuring tension spring connecting device and the piston; a vent hole is also provided at this end of the cylinder; A manual switch valve is fixedly connected to the other end of the cylinder, and a scale line is provided on the cylinder between the piston and the manual switch valve. The upper and lower sides of the scale line are marked with atmospheric pressure values ​​and atmospheric pressure values ​​respectively. The end face of the piston on one side of the manual switch valve corresponds to the zero scale position of the scale line, and the piston also serves as a scale pointer for the force measuring tension spring.

2. An experimental device for measuring atmospheric pressure according to claim 1, characterized in that: The force measuring tension spring connection device includes a connecting seat, a pull rod, and an adjusting nut. A threaded connector is provided at one end of the connecting seat, a guide hole is provided through the connecting seat, the pull rod passes through the guide hole, the adjusting nut is threadedly connected to the tail end of the pull rod, the adjusting nut contacts the end face of the connecting seat, a first connecting hole is provided at the head of the pull rod, and the connecting seat is threadedly connected to the cylinder through the threaded connector.

3. An experimental device for measuring atmospheric pressure according to claim 2, characterized in that: The piston comprises a piston body and a sealing ring, wherein the sealing ring is elastically sleeved on the head of the piston body, a second connecting hole is arranged on the tail of the piston body, and two ends of the force measuring tension spring are respectively hung on the first connecting hole of the pull rod and the second connecting hole of the piston body.

4. An experimental device for measuring atmospheric pressure according to claim 1 or 3, characterized in that: The cylinder is made of transparent material.

5. The experimental device for measuring atmospheric pressure according to claim 1, characterized in that: A sealing ring is arranged between the manual switch valve and the cylinder.

Images