CN220583487U - Constant flow hole fixture and period checking device - Google Patents

Abstract

The utility model discloses a constant flow hole clamp and a period checking device, wherein the constant flow hole clamp is used for installing a constant flow hole and comprises a base, an upper pressing ring and an upper cover, wherein a through hole is internally formed in the base, the upper pressing ring is connected with the upper cover, the upper pressing ring is arranged between the end surfaces of the base and the upper cover, an air inlet of the constant flow hole clamp is formed at one end, far away from the upper pressing ring, of the base, and an air outlet of the constant flow hole clamp is formed at one end, far away from the upper pressing ring, of the upper cover; the constant flow hole is arranged in the through holes of the base, the upper pressing ring and the upper cover, a plurality of rubber diaphragms which are used for elastically sealing the constant flow hole are arranged in the base, and the constant flow hole passes through the plurality of rubber diaphragms. The fixture disclosed by the utility model can adapt to the checking and positioning of constant flow holes with various specifications, and can ensure the air tightness of the constant flow holes; the period checking device can realize periodic checking of the constant flow hole, and the quality of the constant flow hole is ensured.

Description

A constant flow hole fixture and period verification device

Technical field

The utility model relates to the technical field of cigarette detection and calibration. Specifically, it is a constant flow hole fixture and a period verification device.

Background technique

Tobacco-specific constant flow orifice CFO (Critical Flow Orifice) is a standard instrument used in various tobacco-specific testing instruments such as suction resistance tester, ventilation rate tester, smoking machine puff curve tester, etc. Its main function is to control the gas flow rate. Constant to meet the measurement requirements of the flow rate.

The tobacco industry calibrates tobacco-specific constant flow holes in accordance with JJG (Tobacco) 16-2002 "Calibration Regulations for Constant Flow Holes Special to Tobacco". During the calibration process, compressed air, flow meters, differential pressure meters, etc. are required. The calibration cycle is one year. In actual production, it is necessary to frequently use suction resistance testers, ventilation rate testers and other equipment. The constant flow hole, as a generator of stable air flow, is susceptible to tobacco contamination, blockage, etc. It is impossible to guarantee that the constant flow hole will be used twice a year apart. The stability during the first calibration period, however, the "tobacco-specific gas flow standard device" occupies a large area and is complicated to operate and use, so it cannot be promoted to enterprises. Therefore, it needs to be checked regularly during daily use to ensure that the air flow in the air path is stable within the range of measurement requirements and to determine whether the flow rate of the constant flow hole changes.

Moreover, during periodic inspections, the airtightness of the constant flow hole cannot be guaranteed and the accuracy of changes in the flow rate of the constant flow hole cannot be determined.

Utility model content

The purpose of this utility model is to provide a constant flow hole fixture and a period checking device, which are used to solve the problem in the prior art that the constant flow hole calibration cycle is long and it is difficult to ensure the stability of the constant flow hole during two calibrations, and to ensure Air tightness issues of constant flow holes during inspection or other verification work.

The utility model solves the above problems through the following technical solutions:

A constant flow hole fixture used to install a constant flow hole, including a base with a through hole, an upper pressure ring and an upper cover. The base is connected to the upper cover, and the upper pressure ring is arranged on the end surface of the base and the upper cover. Between them, the end of the base away from the upper pressure ring is formed with an air inlet of the constant flow hole fixture, and the end of the upper cover away from the upper pressure ring is formed with the air outlet of the constant flow hole fixture; the constant flow hole is installed on the base, the upper pressure ring and the upper cover In the through hole, several rubber diaphragms are provided in the base to elastically seal the constant flow holes, and the constant flow holes are arranged through several rubber diaphragms.

As a further improvement, the base is plugged into the upper cover, and no less than one O-shaped sealing ring is provided between the outer surface of the base and the upper cover.

As a further improvement, the upper pressing ring is threadedly connected to the base, so that several rubber diaphragms are extruded and installed through the upper pressing ring.

As a further improvement, the constant flow hole is arranged vertically with the air inlet of the constant flow hole clamp.

As a further improvement of the present invention, a constant flow hole period checking device is characterized in that it includes a negative pressure generator, a mass flow meter, a differential pressure meter, a thermometer, an atmospheric pressure meter and the constant flow hole fixture. The negative pressure generator The constant flow orifice fixture and mass flow meter are connected in sequence. The constant flow orifice to be inspected is set on the constant flow orifice fixture. The negative pressure required for the constant flow orifice to work is generated through the negative pressure generator. The mass flow meter measures the pressure of the constant flow orifice. The upstream mass flow and differential pressure meter measure the pressure difference between the upstream and downstream of the mass flow meter. The thermometer and barometric pressure meter measure the ambient temperature and atmospheric pressure to check the flow value of the constant flow orifice.

As a further improvement, a dryer is provided between the mass flow meter and the constant flow hole fixture.

As a further improvement, the positive pressure port of the negative pressure generator is connected to the compressed air, the negative pressure port of the negative pressure generator is connected to the air outlet of the constant flow hole fixture, and the exhaust port of the negative pressure generator is connected to the atmosphere.

As a further improvement, the compressed air is generated by a compressor or a compressed air source.

Compared with the existing technology, this utility model has the following advantages and beneficial effects:

(1) This utility model has a constant flow hole clamp that can be adapted to the verification and positioning of constant flow holes of various specifications by setting a rubber diaphragm, and can ensure the airtightness of the constant flow hole by setting an O-shaped sealing ring and a rubber diaphragm. performance, providing guarantee for the verification of constant flow holes.

(2) A constant flow hole period checking device of the present invention can realize regular checking of the constant flow hole, eliminate the influence caused by the deviation of the constant flow hole during the production process; and remove the moisture in the atmosphere by setting up a dryer , prevent the constant flow hole from being damaged due to the entry of moisture, and ensure the quality of the constant flow hole.

Description of the drawings

Figure 1 is an appearance structural diagram of a constant flow hole fixture of the utility model;

Figure 2 is a cross-sectional perspective view of a constant flow hole fixture of the present utility model;

Figure 3 is a schematic cross-sectional structural diagram of a constant flow hole clamp of the present utility model;

Figure 4 is a schematic structural diagram of the rubber diaphragm of a constant flow hole clamp according to the present invention;

Figure 5 is a schematic connection diagram of a period checking device for a constant flow hole of the present invention;

Figure 6 is a reference diagram showing the relationship between the air compressibility factor, temperature and absolute pressure of the air outlet of the constant flow hole clamp in the actual situation of the present invention.

Reference symbols: 1-base; 2-upper pressure ring; 3-upper cover; 4-constant flow hole; 5-rubber diaphragm; 6-O-shaped sealing ring.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only part of the embodiments of the present utility model, not all implementations. example. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model.

Example 1:

The constant flow hole has the characteristic that the volume flow rate remains basically unchanged when the pressure at the inlet end changes. However, due to the influence of the use environment and materials, as the use time increases, the constant flow hole will also produce a certain amount of loss or pollution, resulting in Its value changes. Therefore, periodic verification of constant flow orifices is required.

Referring to Figures 1-4, a constant flow hole fixture is used to install the constant flow hole of the constant flow hole period verification device, including a base 1 with a through hole, an upper pressure ring 2 and an upper cover 3, a constant flow hole 4 is arranged in the through hole of the base, the upper pressure ring and the upper cover, wherein the upper cover and the base are closed, the upper pressure ring is located between the upper cover and the base and offsets the upper cover and the base respectively, and the base is away from the upper pressure ring. One end of the ring is formed with an air inlet of a constant flow hole fixture for connecting to the dryer and mass flow meter; one end of the upper cover away from the upper pressure ring is formed with an air outlet of a constant flow hole fixture for connecting with the negative pressure generator. connect. Preferably, the base and the upper cover are pluggable and connected, and at least one O-shaped sealing ring 6 is provided between the outside of the base and the upper cover to ensure the airtightness of the constant flow hole clamp.

Further, a rubber diaphragm 5 is provided in the through hole of the base, and the rubber diaphragm is against the end of the upper pressure ring. The upper pressure ring is connected to the base through threads, and the rubber diaphragm is pressed into the base. One end of the constant flow hole is The end of the constant flow hole is set through a rubber diaphragm, and one end of the constant flow hole is elastically sealed through the rubber diaphragm in the base to ensure that the airflow only flows through the constant flow hole.

Preferably, the constant flow hole is arranged perpendicularly to the air inlet of the constant flow hole clamp.

The constant flow hole fixture of the present invention can be adapted to the verification and positioning of constant flow holes of various specifications by setting a rubber diaphragm, and can ensure the airtightness of the constant flow hole by setting an O-shaped sealing ring and a rubber diaphragm. Provides guarantee for verification of constant flow holes.

Example 2:

As shown in Figure 5, a constant flow orifice period verification device includes a negative pressure generator, a constant flow orifice fixture, a dryer, a mass flow meter, a differential pressure meter, a thermometer and an atmospheric pressure meter. The negative pressure generator, constant flow orifice The flow hole fixture, dryer, and mass flow meter are connected in sequence. The constant flow hole to be verified is set on the constant flow hole fixture. The negative pressure required for the operation of the constant flow hole is generated through a negative pressure generator. The mass flow meter measures the upstream of the constant flow hole. Mass flow and differential pressure meters measure the pressure difference between the upstream and downstream of the mass flow meter. The thermometer and barometric pressure meter measure the ambient temperature and atmospheric pressure. The upstream and downstream pressure differences, ambient temperature and atmospheric pressure of the mass flow meter are then converted into the upstream volume of the constant flow orifice. The flow rate is the measurement result of the flow value of the constant flow hole.

Specifically, the positive pressure port of the negative pressure generator is connected to the compressed air, and the negative pressure port of the negative pressure generator is connected to the air outlet of the constant flow hole fixture to provide the constant flow hole with the negative pressure required for normal operation. The negative pressure generator The exhaust port is connected to the atmosphere. The air inlet of the constant flow hole fixture is connected to the air outlet of the dryer, and the air inlet of the dryer is connected to the air inlet of the mass flow meter, which is connected to the atmosphere through the air inlet of the mass flow meter. In this embodiment, the compressed air is generated by a compressor or a compressed air source, and is connected to the positive pressure end of the negative pressure generator to provide an air source for the negative pressure generator. And a dryer is connected in series between the air inlet of the constant flow hole fixture and the air outlet of the mass flow meter. The moisture in the atmosphere is removed through the dryer to prevent the constant flow hole to be checked from being damaged due to the entry of moisture; the pressure difference meter is set Between the constant flow hole fixture and the dryer, and at the air inlet of the constant flow hole fixture, it is used to measure the pressure difference between the constant flow hole air inlet and the atmosphere.

The measurement method of constant flow orifice flow value, the specific steps are:

S1. Collect the pressure difference P1 measured by the differential pressure meter and the atmospheric absolute pressure P2 measured by the barometer. Calculate the absolute pressure P at the air inlet of the constant flow hole fixture. The calculation formula is: P=P2-P1;

S2. Collect the atmospheric temperature T measured by the thermometer;

S3. The processing system uses the following formula to calculate the flow rate Q _{(P, T)} of the constant flow hole, and compares whether the flow rate Q _{(P, T)} of the constant flow hole is within the standard flow range of the constant flow hole of the tested specifications to achieve Periodic verification of constant flow orifices.

Among them, P _N is the atmospheric pressure under standard conditions, generally taken as 101325Pa; T _N is the temperature under standard conditions, taken as 237.15KQ _N is the flow rate under standard conditions; Z _N is the gas compressibility factor under standard conditions, the gas of air The compressibility factor is 0.99941; P is the air pressure at the dryer outlet under actual conditions, which is the difference between the absolute atmospheric pressure measured by the barometer and the pressure difference measured by the differential pressure meter; T is the air pressure at the dryer outlet under actual conditions. The air temperature is the same as the ambient temperature, which is the temperature of the atmosphere measured by the thermometer; Z _{(P, T)} is the air compressibility factor of the air outlet of the constant flow hole fixture under actual conditions, which is dimensionless, as shown in Figure 6. It can be obtained by looking up the table.

The utility model's constant flow hole period checking device can realize regular checking of the constant flow hole and eliminate the influence caused by the deviation of the constant flow hole in the production process; and by setting up a dryer to remove moisture in the atmosphere, prevent constant The flow hole is damaged due to the ingress of moisture.

Although the present utility model is described here with reference to illustrative embodiments of the present utility model, the above-mentioned embodiments are only preferred implementation modes of the present utility model. The implementation modes of the present utility model are not limited by the above-mentioned embodiments. It should be understood that Numerous other modifications and embodiments can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed in this application.

Claims (8)

1. A constant flow hole fixture used to install a constant flow hole, which is characterized in that it includes a base with a through hole, an upper pressure ring and an upper cover. The base is connected to the upper cover, and the upper pressure ring is arranged on Between the end face of the base and the upper cover, an air inlet of the constant flow hole fixture is formed on the end of the base away from the upper pressure ring, and an air outlet of the constant flow hole fixture is formed on the end of the upper cover away from the upper pressure ring; the constant flow hole is installed on the base, In the through holes of the upper pressure ring and the upper cover, several rubber diaphragms are provided in the base to elastically seal the constant flow holes, and the constant flow holes are arranged through several rubber diaphragms. 2. A constant flow hole fixture according to claim 1, characterized in that the base is plugged into the upper cover, and no less than one O-shaped sealing ring is provided between the outer surface of the base and the upper cover. 3. A constant flow hole clamp according to claim 1, characterized in that the upper pressure ring is threadedly connected to the base, so that several rubber diaphragms are extruded and installed through the upper pressure ring. 4. A constant flow hole clamp according to claim 1, characterized in that the constant flow hole is arranged perpendicularly to the air inlet of the constant flow hole clamp. 5. A constant flow hole period verification device, characterized in that it includes a negative pressure generator, a mass flow meter, a differential pressure meter, a thermometer, an atmospheric pressure meter and a constant flow hole fixture as claimed in any one of claims 1 to 4, The negative pressure generator, constant flow hole fixture and mass flow meter are connected in sequence. The constant flow hole to be checked is set on the constant flow hole fixture. The negative pressure required for the constant flow hole to work is generated by the negative pressure generator, and the mass flow meter measures the constant The mass flow rate upstream of the flow orifice, the differential pressure meter measures the pressure difference upstream and downstream of the mass flow meter, and the thermometer and barometric pressure meter measure the ambient temperature and atmospheric pressure to check the flow value of the constant flow orifice. 6. A constant flow hole period checking device according to claim 5, characterized in that a dryer is provided between the mass flow meter and the constant flow hole fixture. 7. A constant flow hole period checking device according to claim 5, characterized in that the positive pressure port of the negative pressure generator is connected to the compressed air, and the negative pressure port of the negative pressure generator is connected to the outlet of the constant flow hole fixture. Air port, the exhaust port of the negative pressure generator is connected to the atmosphere. 8. A constant flow hole period checking device according to claim 7, characterized in that the compressed air is generated by a compressor or a compressed air source.