WO2018010894A1 - Gas meter calibration system in a closed pressure circuit - Google Patents

Abstract

The invention relates to a test system for gas meter calibration in a closed circuit under high pressure. The test system comprises a high-pressure flow circuit and a medium flow generator, for example, a turbine unit or an air blower system. Furthermore, a temperature control system, for example, a thermostabilizing chamber or a cooler, which can be operatively connected to the circuit, and a delivery rate control unit for the medium are provided. In addition, a system of the calibration meters, which can be operatively connected to said closed circuit, a medium injection system that generates overpressure in the pipeline system, and a system of high-pressure bottles with different gases, which can be operatively connected to the closed circuit of the test system, are provided.

Description

 Gas metering system in a closed pressure circuit

The invention relates to test systems for gas metering in a closed circuit under high pressure and to a method for operating the test system according to the preamble of claims 1 and 9.

Gas flow meter manufacturers often need to test new designs of gas flow meters to verify or verify their accuracy, quality, etc. For the most part, manufacturers have the option of factory-testing gas flow meters using liquids. The test items for liquids can be easily manufactured without excessive costs or time. On the other hand, the gas testing plants can not be created so easily at the factory. Thus manufacturers of gas flow meters usually need to visit and bear considerable costs. This process takes a lot of time and is quite labor intensive. Currently, manufacturers are forced to wait a few weeks or months before they can test new projects and get test results for new models.

Basically, there are three types of Gastestanlagen.

The first type of plant is described in WO2005 / 005938 A1 and relates to a system with a blow-out system. In this blow-out system, a compressor draws in the open air and compresses it in a container. When the tank pressure reaches the test pressure, the air is discharged from the tank, which then flows through a calibration meter and a meter to be tested. Then the air is released back into the open air. The calibration counter and the meter under test measure the gas flow rate as the gas flows back to the atmosphere through the tank. The readings of the calibration meter are used to calibrate the meter under test. The known blow-out system has a short service life, is very cost-intensive, ineffective and extremely noisy.

In WO 2005/005938 A1 a further type of plant is described. It is a gas circulation system. This test facility uses the gas circulation system. The research facility contains a gas cycle, a compressor, a cooler, sound nozzles and sections for the measuring instruments to be tested. The compressor circulates the gas in the gas loop at a desired flow rate. During circulation, the compressor releases heat to the gas in the gas cycle. The cooler cools the gas in the gas cycle to the desired temperature. The meter to be tested, including a sonic nozzle or several sound nozzles, measures the gas flow rate. The sound nozzles act as calibration meters for the meters to be tested. The measured data measured with the meter under test are compared with those of the sonic nozzles to check the accuracy of the meter to be calibrated or to calibrate the meter under test. This research facility is very large, extremely expensive and uses too much power during operation. Due to the huge dimensions, the high price and the high power consumption, many companies have no way of successfully deploying and commissioning the known research facilities on their company premises.

The third type of generic device is disclosed in the following prior art: WO 2005/005938 A1, US 4590790 A, US 20050160784 A1, GB 402954 A and WO 2000058696 A1. This type includes test equipment consisting of a closed flow circuit, a pressure system, a temperature control system, a calibration meter system and a meter test system. The system of calibration meters measures the gas properties of the gas flow circulating in a closed circuit. The meter test system also measures the gas properties of the circulating gas flow in the circuit. The display of the calibration meter system is compared with the display of the meter test system to then calibrate the equipment under test. This third type has several advantages over Types 1 and 2. The test equipment may run for a few hours while the operating life of the blow-out systems is limited. The pressure system in the test system can have smaller dimensions than the compressor in the blow-out system because the pressure system does not require a high pressure build-up. The test system does not require a large container for gas storage under pressure and no degassing to the outside. As a result, this avoids noise problems that commonly occur in blow-out systems. The test facility is smaller in size than the type 2 scientific research facility. The test facility is suitable for indoor installation and even for installation in a corner in the building, while the research facility has fairly large dimensions corresponding to type 2. The test system is usually inexpensive and efficient in operation. It can be placed in the building. The developers can then get the information about various modifications directly and thus the gas flow meter check on site. This saves a lot of time and resources when developing new products.

A major shortcoming of such systems, however, is that a turbine engine of the pressure system is installed in a closed circuit. This means that the medium (gas) is significantly heated and that complex, powerful and power-intensive solutions must be used to ensure the temperature stabilization (cooling) and thus the explosion safety of this engine when using flammable gases as a medium. Other shortcomings of such systems are their complicated design or the non-existent possibility to change the respective gas (medium) in a closed circuit. Then there are problems when gas meters (gas flow meters) are to be tested, which can be operated with a single gas type.

The invention is therefore based on the object to further develop the generic test system so that the deficiencies mentioned are resolved.

This object is solved by the features of claims 1 and 9.

It will be appreciated that the invention is in any case realized when it is a test system for gas counting in a closed circuit under high pressure, comprising the following functionally interconnected components: a closed high-pressure flow circuit,

a medium flow generator, e.g. B a turbine unit or an air blower system which is provided with a hydraulic drive, wherein the flow generator generates a high flow rate of various gases under high pressure in the closed circuit of the test system, a temperature control system, e.g. B. a thermostabilizing chamber or a cooler, which is operatively connected to the circuit,

 a flow rate control unit for the medium at low flow rates,

 a system of calibration meters operationally connectable to said closed loop (401),

 a system of meters to be calibrated, which is operationally connectable to the circuit,

 a medium injection system which generates overpressure in the pipeline system, a system of high-pressure cylinders with different gases which can be operationally connected to the closed circuit of the test system and a filter which cleans in the circuit of the flowing medium.

The system for injecting the medium conveys the required medium into the closed circuit of the system until the desired pressure is reached. Thus, the system is operated in the closed cycle. If the turbine of the medium flow generator is turned on, a medium flow is created in the pipeline of the closed circuit of the system. The thermostabilizing chamber absorbs the medium flow and monitors its temperature. The system of calibration meters and the system of meters to be calibrated measure the flow of the medium that flows through the system piping. The error is determined by comparing the respective quantities of medium measured by the counter to be calibrated and the calibration counter under standardized conditions.

The gas metering system in the closed pressure circuit can be compact and efficiently designed. This system makes it possible for manufacturers of gas flow meters to quickly get feedback (feedback) on any necessary design changes to the gas flow meters. This allows both time and other resources to develop new products. save up. In addition, this system is characterized by a much lower power consumption compared to gas circulation systems and is therefore more economical.

Further expedient and advantageous embodiments of the invention will become apparent from the dependent claims.

An expedient embodiment of the invention provides that the system of the meters to be calibrated is arranged according to the system of the calibration meters in the sense of the flow direction. The pipeline of the high-pressure circuit is provided with a device for emergency degassing of the circuit, including a gas display. Between the sections of the pipeline of the high-pressure circuit, vibration-damping intermediate pieces are installed. Further, a vacuum compressor for removing residual gas from the closed high pressure circuit and an inert gas unit is provided, which is connected to the pipeline of the high pressure circuit (401).

A further advantageous embodiment of the invention provides:

an electric motor, which is arranged outside the closed flow circuit and drives, with the aid of a hydraulic pump, a hydraulic motor, which is located in the closed medium circuit,

 a turbine, which is arranged in a closed circuit, is driven by the hydraulic motor and which generates and controls the gas flow velocity in the closed pipeline system of the test system,

- An additional closed circuit of the hydraulic drive of the medium flow generator, which is provided with an electric motor, a hydraulic pump, a radiator and a hydraulic motor that drives the turbine. The invention will now be explained in more detail with reference to exemplary embodiments. Show it:

Fig. 1 is a block diagram of the gas metering system in the closed pressure circuit and

Fig. 2 is a functional diagram of the gas metering system in the closed

 Pressure circuit.

Figures 1-2 and the following description disclose specific examples of the invention to guide those skilled in the art to the practice and best practice of this invention. In order to explain the essential principles of the present invention, some aspects of the invention are simplified or omitted. The embodiments covered by this invention and described in the embodiments will be understood by those skilled in the art. The person skilled in the art will also understand the particularities described below, which can be combined in various ways in order to achieve numerous embodiments of this invention. Thus, the present invention is not limited to the particular examples described below and is defined by the claims of the invention and their equivalents.

Fig. 1 shows a gas metering area 400 in the closed pressure circuit as an embodiment of the invention.

Fig. 2 shows a test system 500 as an embodiment of the invention. Test system 400, 500 according to the invention contains:

 a closed high-pressure flow circuit 401, 501, which may contain gas under pressure,

 a medium flow generator (a turbine unit, an air blower system)

402, 502 with a hydraulic drive; the medium flow generator is designed so that it can develop a high flow rate of various gases under high pressure within the closed circuit of the plant,

 a temperature control system (a thermostabilizing chamber, a cooler)

403, 503 connected to said closed circuit and capable of adjusting the temperature of said compressed gas,

 a flow rate control unit for the medium at low flow rates 404, 504,

 a system of calibration meters (a calibration line) 405, 505 which is connected to said closed circuit and allows flow measurement of said compressed gas,

 a system of meters to be calibrated (an operating line) 406, 506 which is connected to said closed circuit and allows the connection of the meter under test in order to measure the flow of said compressed gas,

 a medium injection system 407, 507 to create overpressure in the piping system (closed loop) of the plant; the medium injection system is designed so that different gases can be pumped into the system until the desired pressure is reached,

a system of high-pressure cylinders 408, 508 with different gases, which makes it possible to convey various gases under high pressure in the closed circuit of the test system, - A vacuum compressor 413, 513, which is set up so that residual air, various residual gas and moisture from the closed circuit of the test system are removed and

 - A filter 411, 511, to remove the impurities from the circulating in the closed circuit of the test system flow and to avoid contamination of the calibration counter.

For a better understanding of the invention, the following definitions are to be considered.

The flow loop 401, 501 comprises a pipeline or a closed structure containing a gas.

The medium flow generator (the turbine unit, the air blower system) 402, 502 is provided to develop a high flow rate of said gas under high pressure in the closed loop 401, 501 of the testing equipment 400, 500. The medium flow generator is characterized by the following features:

 Presence of an electric motor 516, which is arranged outside the closed flow circuit and drives by means of a hydraulic pump 517 a hydraulic motor 519, which is located in the closed medium circuit 401, 501,

 - presence of an additional closed circuit 525 with a hydraulic medium; the hydraulic medium helps transmit the torque (motion) from the electric motor outside the high-pressure flow circuit 401, 501 to the turbine within the high-pressure fluid circuit 401, 501,

Presence of a turbine 520 within the closed high-pressure flow circuit 401, 501 driven by the hydraulic motor 519; the turbine 520 is provided to close the gas flow in the closed Control piping system of the test facility; when the turbine 520 is switched on, a medium flow is created in the pipeline of the system; the main advantages of this medium flow generator 402, 502 are:

 - Arrangement of the electric motor 516 outside the (explosive) medium; in contrast to the known technical solutions, it is no longer necessary to ensure the explosion safety and explosion protection of the equipment;

 lack of heating of the medium by the electric motor 516,

 Considerably reducing power consumption to cool the medium

- The presence of a hydraulic fluid cooler 518 to ensure an even higher degree of closed-loop temperature stabilization.

The temperature control system (the thermostabilizing chamber, the cooler) 403, 503 is provided to cool the medium (gas under pressure) and maintain a constant gas temperature. The thermostabilizing chamber 403, 503 receives the medium flow and monitors its temperature.

The flow control unit 404, 504 of the medium at low flow rates is characterized in that it contains parallel built-in lines of the sound nozzles. These sound nozzle lines ensure high stability of movement of the medium flows with small medium volume flows.

The flow control unit is also characterized by including a system of shut-off valves that helps to make the necessary changes and regulate the flow rate range. The system of calibration meters (the calibration line) 405, 505 consists of calibration counters, absolute pressure transmitters and temperature sensors, the information of which is transmitted to the controllers 414, 514. In order to convert the meter readings under operating conditions to normal conditions, the displays of the absolute pressure transmitters and the temperature sensors are used.

The system of meters 406, 506 to be calibrated consists of a telescopic compensator 415, 515, a counter to be calibrated, an absolute pressure transmitter and a temperature transmitter whose measurement data are transmitted to the control system 414, 514. The telescopic compensating element 415, 515 makes it possible to attach the meter to be calibrated to the operating line airtight. In order to convert the counter readings from working conditions to normal conditions, the measuring data of the absolute pressure transmitters and the temperature sensors are used.

The meter-to-calibrate system 406, 506 is required to check (calibrate, calibrate) the meter. It consists of a gauge to be tested, set up for testing with a said gas, and interface units to connect the meter to be tested with the flow circuit 401, 501 of the axis of the measuring line. The system of meters 406, 506 to be calibrated is connected to said closed loop 401, 501 and arranged so that the meter to be tested can be connected to it to measure the flow of said compressed gas. The system 406, 506 is characterized by the presence of some parallel working cells. Each of the working cells can each accommodate one meter to be tested (to be calibrated, calibrated) (gas flow meter). Each of said work cells is intended for a specific flow range. The system 400, 500 is characterized in that the system of the meters 406, 506 to be calibrated is arranged in the sense of the direction of flow according to the system of the calibration meters 405, 505. This avoids that the impurities from the meters to be calibrated can get into the calibration meters.

The meter to be tested and one or more calibration meters measure the velocity of the gas flow circulating in the system piping. The controller 414, 514 compares the readings from calibration meters and the meters under test to verify the accuracy of the meter under test or to calibrate the meter to be tested.

The measuring section for mounting the meter to be calibrated (to be calibrated) is formed from a set of standardized components, namely conical transition pieces and flanged sections of the pipeline (straight sections). The components of the measuring section are centered to align them axially. This is achieved with the help of procedural pedestals, which can be moved along the framework via horizontal guides. The compressor is used to control the telescopic compensator and slides. In order to securely support the elements of the measuring section, a rigid support structure (metal framework) is arranged along the entire measuring section. The connecting pipes are made of stainless steel and designed to connect all modules of the test system together.

The controller 414, 514 controls the test system automatically and is provided for the evaluation of the displays of the pressure and temperature sensors and the calibration counter and the meters to be calibrated. This controller 414, 514 aims to compare the measurement data of the calibration cells and the counter to be tested in the said system of the counters 406 to be calibrated and subsequently to calibrate the test device to be tested if necessary. The medium injection system 407, 507 serves to deliver the gas into the circuit 401, 501. The two-deck system of high-pressure bottles 408, 508 of the medium injection system 407, 507 is provided in order to build up the required pressure in the piping system (in the closed circuit) 401, 501 of the test system 400, 500. In each case, different gases can be blown into the pressure system of the test system until the desired pressure is reached. The related system of high-pressure bottles on two levels with the different gases 408, 508 consists of a subsystem of bottles with a pressure of 200 - 300 bar and a subsystem of bottles with a pressure of 30 - 50 bar, preferably with a separate heating. The gas required for the tests (calibration, calibration) of knives (gas flow meters) is supplied from the bottles with a pressure of 200 - 300 bar to the cylinders with a pressure of 30 - 50 bar. Furthermore, the gas is pumped from the bottles with the pressure of 30-50 bar into the closed high-pressure circuit.

The high pressure compressor 409, 509 is set up,

 to return the medium from the closed circuit 401, 501 into the gas cylinders,

 - To ensure such a pressure increase in the circuit 401, 501 and the gas cylinders, which is equal to the pressure drop in the test system 400 and in the gas cylinder system 408, 508.

A damping container 410, 510 contributes to the fact that the pressure in the path from the circuit 401 to the compressor 409, 509 is reduced continuously. It ensures the protection of the compressor against possible damage when there is a high pressure in the circuit 401, 501.

The filter 411, 511 is installed in the piping of the high-pressure circuit 401, 501. It is designed to remove impurities from the closed circuit 401, 501 of the test system 400, 500 circulating flow to remove and prevent contamination of the calibration counter.

The inert gas unit 412, 512 with the high pressure line circuit 401, 501 supplies inert gas into the closed high pressure circuit 401, 501.

The vacuum compressor 413, 513 is provided for the removal of residual gases from the closed circuit 401, 501.

The high pressure pipeline circuit 401, 501 with a gas removal device of the emergency circuit 421, 521 is provided with the indicator gas.

The operation of the test system 400, 500 is:

 - A specific gas, which is necessary for the examination of the respective counter (gas flow meter), is conveyed from the system of gas cylinders 408, 508 of the medium injection system 407, 507 in the closed circuit 401, 501 of the test system 400, 500. That is, the medium-injection system 407, 507 continuously supplies the circuit 401, 501 with this gas until the required pressure is reached.

 - After the predetermined medium pressure (gas pressure) in the circuit 401, 501 is reached, the medium flow generator 402, 502 triggers the flow movement at a predetermined speed in the circuit 401, 501.

 The said flow flows through the system of calibration meters 405, 505 and the system of meters 406, 506 to be calibrated.

The controller 414, 514 compares the flow rates of said gas measured respectively by the system of the calibration meters 405, 505 and the system of meters 406, 506 (of the meter under test) to be calibrated, and subsequently calibrates the meter to be inspected with respect the determined comparison results. Between the thermostabilizing chamber 403, 503 and the attenuator 405, 505 vibration damping spacers are used. These prevent the transmission of mechanical high-frequency oscillations from the turbine 520 including the hydraulic motor 519 to the calibration line 405, 505 and from the calibration line to the operating line 406, 506.

In order to avoid the transmission of "acoustic pulsations" (noise pulsation) from the calibration line to the operating line, a flow conditioning unit is used.

If a fan is switched on, then a gas flow is established in the pipeline of the test system. The gas flow rate can be controlled by changing the speed of the fan. One of the calibration meters monitors the flow rate (m ³ / hour). The device technology of the test system counts the pulses which are generated by the counter to be calibrated and by the calibration counter within a predetermined interval. This number is then multiplied by a respective pulse valency, which is set individually for each counter to be calibrated and the calibration counter. In this way, the gas quantities are determined under operating conditions. Then the conversion of the gas quantities to normal conditions takes place. The error is calculated by comparing the quantities of gas measured by the meter to be calibrated and the calibration meter under normal conditions.

There are some ways to limit the measurement cycle. It may be a predetermined number of pulses of a master counter, a predetermined amount of gas or a predetermined test duration. Alternatively, the measuring cycle can be manually restricted. The gas metering system 400, 500 in the closed pressure circuit has numerous advantages compared to the known inventions. The test system 400, 500 can run for several hours. The medium does not need to be discharged outside. Consequently, the mentioned noise problems that normally arise when blowing out the system can be avoided. The dimensions of the test system 400, 500 are smaller than those of the known systems. The test facility 400, 500 may be small enough to allow indoor installation in a building. The test system 400, 500 is cheaper compared to the known test systems. It is equipped with less expensive components and is therefore affordable for many companies.

As mentioned above, the Southwest Research Institute Test Facility 200 uses a very large compressor that delivers too much heat to the gas. Thus, the Southwest Research Institute test facility 200 requires a very large cooling system. A large compressor and a large cooling system will inevitably consume a lot of electrical energy.

The medium flow generator 402, 502 of the claimed test rig 400, 500 has an electric motor 516 disposed outside of the closed circuit 401, 501. The energy developed by the electric motor 516 during operation is dissipated into the environment. So there is no direct contact, and the heat is not transferred to the medium in the closed circuit 401, 501. The turbine 520 with the hydraulic motor 519 of the test facility 400, 500 is relatively small. Thanks to the 519 hydromotor, the medium is heated very little. There is an additional circuit 525 with a hydraulic fluid flowing through a radiator 518. Thus, it is practically completely avoided that the energy developed by the flow generator 502 reaches the medium 401, 501 in a closed circuit. Thus, the test equipment 400, 500 needs only a small thermostabilizing chamber 403, 503 to remove the heat that is in the medium due to its loading. movement and arises as a result of the hydraulic motor rotation. Consequently, to stabilize the temperature of the medium, much less power is required than in the prior art test equipment.

The use of a double-decker system with 508 gas cylinders allows a fast change of medium in a closed circuit and thus the performance of gas metering precisely with the medium subsequently used in the operation of the gas meters. The preheating 524 of the gas cylinders in the second level 523 of the two-deck system provides additional stabilization of the medium temperature in a closed circuit.

Due to the use of the hydraulic drive for the turbine 520 in the medium flow generator 502 complicated technical solutions are eliminated to ensure the explosion safety of the flow generator and the entire test system.

Claims

Claims 1. Closed-cycle gas metering test system (400) under high pressure, comprising:  a high pressure flow circuit (401),  a medium flow generator (402), e.g. B is a turbine unit or an air blower system,  a temperature control system (403), e.g. B. a thermostabilizing chamber or a cooler, which is operatively connected to the circuit,  a flow rate control unit (404) for the medium,  a system of calibration meters (405) operationally connectable to said closed loop (401),  - A pipeline system in the overpressure generating medium-injection system (407) and  a system of high-pressure cylinders (408) with different gases operatively connectable to the closed circuit of the test equipment, 2. testing system (400) according to claim 1,  characterized,  in that the system of the counters (406) to be calibrated is arranged according to the system of the calibration counters (405) in the direction of the flow direction, in that the pipeline of the high-pressure circuit (401) is provided with an apparatus for emergency degassing of the circuit (421) together with a gas display, that vibration-damping intermediate pieces are installed between the sections of the pipeline of the high-pressure circuit (401), a vacuum compressor (413) is provided for removing residual gas from the closed high-pressure circuit (401), and  there is an inert gas unit (412) connected to the pipeline of the high pressure circuit (401). 3. test system (500) according to claim 1,  marked by  an electric motor (516) disposed outside the closed flow circuit (401, 501) and by means of a hydraulic pump (517) driving a hydraulic motor (519) located in the closed medium circuit (401, 501),  - A turbine (520), which is in the closed circuit (401, 501) is driven by the hydraulic motor (519) and which generates and controls the gas flow velocity in the closed piping system of the test system and  an additional closed circuit (525) of the hydraulic drive of the medium flow generator (402, 502) provided with an electric motor (516), a hydraulic pump (517), a radiator (518) and a hydraulic motor (519), which drives the turbine (520). 4. test system (400) according to claim 1,  marked by  a flow rate control unit for the medium at small volume flows (404, 504) with sound nozzles and a system of a shut-off valve for the regulation of the range of flow rates of the flow. 5. test system (400) according to claim 1 with calibration cells, characterized, that the calibration cells are connected in parallel and  each calibration cell contains a calibration counter (gas flow meter). 6. testing system (400) according to claim 1,  characterized,  in that a medium injection system (407, 507) having a two-deck system of high-pressure bottles with different gases (408, 508), a high-pressure compressor (409, 509) and a damping container (410, 510) is arranged and connected 7. test system (400) according to claim 6,  characterized,  that the two-deck system of high-pressure bottles (408, 508) with different gases with a subsystem (522) of gas cylinders with a pressure of 200 - 300 bar and a subsystem (523) of gas cylinders with a pressure of 30 - 50 bar with preheating (524) or all working together, that the cylinder gas required for the tests (calibration, calibration) of the meters (the gas flow meter) is conveyed at a cylinder pressure of 200 - 300 bar into the gas cylinders at 30 - 50 bar, and  that then the gas is pumped from the gas cylinders under a pressure of 30 - 50 bar in the closed high-pressure circuit. 8. Test system according to claim 6,  characterized,  that the system works from high pressure cylinders with different gases (408, 508). 9. A method for the operation of the test system according to one of claims 1 to 8, characterized in that a specific gas required for the testing of a counter (a gas flow meter) is conveyed from the system of gas cylinders (408, 508) of the medium injection system (407, 507) into the closed circuit (401, 501) of the test system (400, 500) with the medium injection system (407, 507) providing continuous pressure build-up in the circuit (401, 501) until a desired pressure is reached,  that upon reaching the required medium pressure (gas pressure) in the circuit (401, 501) a flow movement with a predetermined speed in the circuit (401, 501) is generated,  that said flow flows through a system of calibration meters (405, 505) and a system of meters to be calibrated (406, 506),  that the flow measurement data of said gas are compared by the system of the calibration meters (405, 505) and by the system of meters to be calibrated (of the meter to be tested) in the control, and  then, if necessary, the measuring device to be tested is calibrated. 10. The method according to claim 9,  characterized,  in that a hydraulic drive is used for the medium flow generator (402, 502) in which a turbine (520) is driven by means of a hydraulic motor, which in turn is driven by a hydraulic fluid supplied by a hydraulic pump (517) and Hydraulic pump is in turn driven by an electric motor (516),  in that the electric motor (516) is arranged outside the closed circuit (401, 501) and in that a thermostabilizing chamber (503), a cooler for the hydraulic fluid (518) and a preheating (524) of the gas cylinders are used. 11. The method according to claim 9,  characterized,  a flow rate control unit is used at small flow rates (a sonic nozzle unit) (404, 504) to ensure the high stability of the medium flow at low flow rates.