CN2081082U

CN2081082U - Flow tester for capillary tube of cold-producing medium

Info

Publication number: CN2081082U
Application number: CN 90223779
Authority: CN
Inventors: 孙文臣; 邓同瑞
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-11-13
Filing date: 1990-11-13
Publication date: 1991-07-17

Abstract

The utility model relates to a flow tester for the capillary tube of a cold-producing medium, mainly comprising a nitrogen gas source, a heat exchanger, a controlling valve, an equalizer, a resistance element, a mercury pressure meter, a safety, etc. The utility model adopts a pressure amplifying principle and makes use of the automatic compensating measure of the temperature and the pressure to enhance the testing precision, and the tester is not affected by the change of the environmental temperature and pressure and the change of a flow source, enlarging the using range of the pressure and the temperature.

Description

Flow tester for capillary tube of cold-producing medium

The utility model relates to a kind of cold-producing medium kapillary flow detector of a kind of refrigeration industry kapillary making, traffic alignment.

At present, in refrigeration research and the commercial production, usually relate to the making kapillary, and determine its flow---pressure characteristic, capillary detection method commonly used has two kinds, first nitrogen flow method, as " U.S. heating refrigerating conditioner engineering Shi Xuehui standard ", (ASHRAE28-78) test method of cold-producing medium kapillary flow, it two is that pressure differential method detects the kapillary flow, as " refrigerator, air-conditioner repair handbook light industry publishing house (in July, 1989), these two kinds of methods all are widely used in production testing or other tests, but in producing a certain specification refrigeration plant in batch, the flow capillaceous of same specification---pressure characteristic requires when length variations is very little, the pressure loss can have significant variation on measuring cell, more than two kinds of test methods be difficult to accomplish.

The purpose of this utility model is to solve cold-producing medium kapillary flow to detect and be not subjected to gas meter and manometric precision is low, cost is high restriction and the resistance element of drag characteristics such as employing, and also adopt pressure to amplify and improve measuring accuracy and enlarge the working pressure temperature range, variation for stream source, environment temperature, pressure does not need to proofread and correct, and directly shows desired result.

Technical solution of the present utility model is: for single branch road, add the gas of certain flow in import capillaceous, outlet directly communicates with atmosphere, it is poor that the meeting that varies in size of kapillary drag overall produces different inlet and outlet pressures, as long as obtain the pressure characteristic that is directed to flow, just can go out all drag overall characteristics capillaceous, and only just can achieve the goal with the pressure representative of certain flow with the pressure differential absolute value representation.

Kapillary drag overall characteristic depends on inner flow velocity and inner structure roughness, and coarse flow velocity strengthens, and resistance also increases, and also promptly strengthens bleed pressure so add the air source flow velocity, just can reflect flow capillaceous and pressure characteristic significantly, also is the drag overall characteristic.

Add the air source flow velocity, pressure increases, thereby the pressure loss value that is distributed on the kapillary unit length also increases, and when the source of the gas flow velocity reached very big, the capillary pressure loss value of unit length just can obviously test out by certain means.

For two branch roads, add the gas of same traffic at standard capillary and kapillary entrance point to be measured, endpiece all leads to atmosphere, as long as obtain the pressure differential between standard capillary and the kapillary entrance point to be measured, just can express the difference of drag overall characteristic between kapillary to be measured and the standard capillary.

The pressure amplification is meant: bleed pressure increases, and the pressure difference value on the kapillary unit length increases, and pressure difference value is to be reflected by the mercury pressure difference on the U type pipe mercury manometr, and like this, mercury pressure difference corresponding on the unit length kapillary is with regard to increase.As the kapillary of 1 unit length on it corresponding mercury pressure difference be 1mm, amplify through pressure, the kapillary of 1 unit length on it corresponding mercury pressure difference increase such as 2mm, then the kapillary of 0.5 unit length is just reflected by mercury pressure difference 1mm.This detector detects capillary pipe length ratio of precision prior art precision height by experiment.

Because the variation in the variation of environment temperature, pressure and stream source influences two branch roads simultaneously, its influence is to wait the order of magnitude, so this cold-producing medium kapillary flow detector is not subjected to environment temperature, the variable effect in the variation of pressure and stream source has enlarged the usable range of pressure, temperature.

The utility model is to connect a balanced device behind operation valve, a resistance element and a mercury thermometer are respectively arranged on two branch roads behind the balanced device, U type pipe mercury manometr in parallel on the branch road behind two mercury thermometers with two mercury insurances, and the branch terminal behind two mercury thermometers respectively has a kapillary connector, therein the standard capillary that its outlet of series connection communicates with atmosphere behind connector.

The utility model has the advantages that: tested kapillary is when length variations is very little, and its pressure loss can have significant variation on U type pipe mercury manometr; Be not subjected to gas meter and the tensimeter precision is low, cost is high restriction during detection, the resistance element of drag characteristics such as employing and pressure amplify and improve measuring accuracy.During detection, stream source, environment temperature, when pressure changes, do not need to do correction, and directly show desired result.

Below in conjunction with accompanying drawing present embodiment is described in further detail:

Fig. 1 is a cold-producing medium kapillary flow detector schematic diagram;

Embodiment:

Dry nitrogen source of the gas 1 in the nitrogen cylinder is through the secondary decompression, by heat exchanger 2, operation valve 3, behind the balanced device 4, bifurcation road and respectively by a resistance element 5 and a mercury thermometer 7 that drag characteristic such as has, a U type pipe mercury manometr 12 that has two mercury insurances 6 in parallel on the branch road behind two mercury thermometers 7, branch terminal behind two mercury thermometers 7, connect a connector 9 respectively, one of them connector 9 connects standard capillary 10, another connector 9 connects kapillary 13 to be measured, atmosphere is all led in each outlet of standard capillary 10 and kapillary to be measured 13, what one side of balanced device 4 was connected with that detector self accuracy test uses seals 11, and a water filling silver mouthfuls 8 is arranged in the mercury insurance 6 in U type pipe mercury manometr 12.

Detection method: the mercury pressure that the pressure differential between examination criteria kapillary 10 and kapillary to be measured 13 inflow points promptly is presented on the U type pipe mercury manometr 12 is poor, come the drag overall of examination criteria kapillary 10 and kapillary to be measured 13 poor, when kapillary 13 inlet pressure overgauge kapillaries 10 inlet pressure to be measured, just cut short the kapillary to be measured 13 of respective length with the kapillary cutting machine.Have only when the pressure differential between standard capillary 10 and kapillary to be measured 13 inflow points equals zero, illustrate that kapillary 13 to be measured and standard capillary 10 have identical drag overall characteristic, be that the flow pressure characteristic is identical, kapillary 13 to be measured has identical flow with standard capillary 10.If kapillary 13 inlet pressure to be measured during less than standard capillary 10 inlet pressure, illustrate kapillary 13 not enough length to be measured.

Special circumstances: when testing under the situation that kapillary 13 to be measured blocks, U type pipe mercury manometr 12 has tangible reaction.

Balanced device 4 in the utility model, its effect are when the branch road drag characteristic is suitable, guarantee that two branch road air flow rates are identical; Resistance element 5 its effects are to change when frequent when kapillary 13 branch road pressure to be measured, do not influence the fluctuations in discharge of standard capillary 10 branch road gases, and guarantee that two branch road air flow rates are identical; Mercury thermometer 7 its effects on two branch roads are the temperature variation of observing two branch roads, are used to detect the variation of the gas flow temperature of two branch roads; 12 its effects of U type pipe mercury manometr are the pressure differentials between examination criteria kapillary 10 and kapillary to be measured 13 inflow points; Two mercurys insurance, 6 its effects on the U type pipe mercury manometr 12 are: prevent that mercury from overflowing into a kind of storage liquid of two branch roads, buffering safety apparatus.Standard capillary 10 of connecting on two branch roads and kapillary to be measured 13, its outlet all communicates with atmosphere.

Claims

1, a kind of cold-producing medium kapillary flow detector, it comprises source nitrogen, operation valve, heat exchanger, connector, it is characterized in that connecting a balanced device 4 in operation valve 3 backs, a resistance element 5 and a mercury thermometer 7 are respectively arranged on two branch roads behind the balanced device 4, U type pipe mercury manometr 12 in parallel on the branch road behind two mercury thermometers 7 with two mercury insurances 6, and the branch terminal behind two mercury thermometers 7 respectively has a kapillary connector 9, the standard capillary 10 that its outlet of connector 9 back series connection therein communicates with atmosphere.

2, cold-producing medium kapillary flow detector according to claim 1, what it is characterized in that a side at balanced device 4 is connected with a test usefulness seals 11.

3,, it is characterized in that being equipped with in the mercury insurance 6 in U type pipe mercury manometr 12 a water filling silver mouth 8 according to claim 1 and 2 described cold-producing medium kapillary flow detectors.

4, cold-producing medium kapillary flow detector according to claim 1 is characterized in that resistance element 5 is to be made of the resistance element that waits drag characteristic.