JPS6047537B2 - steam flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a so-called shunt flow meter, which is mainly used for measuring the flow rate of gases such as water vapor.

The internal fluid flow path of this type of flowmeter consists of a straight pipe section into which an orifice plate is inserted and a side path that includes a metering turbine chamber, and a portion of the steam to be measured is diverted from the upstream side of the orifice. After passing through a side passage and jetting out from a nozzle provided at the entrance of the metering turbine chamber to rotate the metering turbine, it is made to join the main stream again on the downstream side of the orifice.

A brake turbine chamber filled with a predetermined brake fluid is provided below the metering turbine chamber, and both turbine chambers are provided with a metering turbine and a brake turbine, respectively. The assembly consisting of the components is rotatably supported and configured to be freely rotated by steam etc. ejected from the nozzle.

Conventionally, the flow rate has been measured by transmitting this rotation to a mechanical rotation counter via an appropriate speed reduction device, or by providing an appropriate rotation detector and counting its output pulses. ing.

Therefore, in this type of flowmeter, the driving torque T1 by the metering turbine is determined by the density r of the steam to be metered and the capacity flow rate ■
The braking torque T2 by the braking turbine is proportional to the square of the braking fluid density γ and the turbine rotational speed ω, and during steady rotation, and if K2 and K2 are proportional constants, or ( However, K...k is a meter constant, K=J訃7;, f is an oscillation frequency, f=Kω/KW is a weight flow rate, and W='·■ holds true.

Therefore, in this type of flow meter, the meter constant K or k
Even if is known, it is not possible to immediately know the weight flow rate W or volumetric flow rate v from the turbine rotational speed ω or pulse oscillation frequency f, and the density r of steam etc. measured by these ω or f
Alternatively, it is necessary to obtain W or ■ by multiplying the square root of the specific volume table by the above meter constant.

Therefore, conventionally, fully automatic and semi-automatic calculation devices have been used to perform this calculation.

Here, the fully automatic type means that a detector is installed that can automatically or directly measure the density r of the steam, etc. to be measured, and as a result, even when the pressure and temperature of the steam, etc. fluctuate, the above-mentioned formula (1) or (2) is calculated, and the semi-automatic method refers to the value of the density r of steam, etc., or the physical quantity that determines these (e.g., vapor pressure or temperature in saturated steam, etc.)
or a physical quantity derived from density r (for example, specific volume 1/r
) is manually set, and the above calculation is performed based on the set value.

However, these conventionally known arithmetic devices have had various problems.

First, regarding mechanical devices, although there are purely mechanical devices that can determine the flow rate integrated value, there is no device that can display the instantaneous flow rate, which is the object of the present invention.

In order to display instantaneous flow rate, a considerable portion of the meter must be electronic, but such hybrid meters are expensive, have a narrow measurement range, and have low calculation accuracy. In addition, in this type of flowmeter, 20
There is a demand for flowmeters ranging from small diameters of about a millimeter to large diameters of 1000mm or more, and the measurement range of the flowmeter can be changed by replacing the orifice plate used and changing the hole diameter. Since it is required to be structured so that it can be changed appropriately at any time,
There are dozens of types of meters, and the meter constant K or k
There are also many different standard values. For this reason, in the past, there has been no mechanical or electronic arithmetic device that can be used commonly across all types of current transmitters and that can easily and reliably set meter constants, etc.

To explain more specifically, when replacing the flow rate transmitter used in combination or changing the orifice or normal pressure, etc., conventional electronic calculation devices have to perform complicated calculations according to the manual for meter constants etc. After doing so, various constants had to be reset according to the results, which was extremely inconvenient.

Furthermore, in the conventional apparatus, there was a problem in that the pitch of the constant to be set becomes rough depending on the conditions, making it impossible to obtain sufficient accuracy. The present invention has been developed based on the above-mentioned viewpoints, and its purpose is to be able to easily connect to any of a wide variety of flow rate transmitters, even when the orifice, normal pressure, etc. are changed. To provide a split-flow steam flow meter equipped with an electronic calculation device that can be easily handled by simply switching a setting switch without using special numerical tables or performing any calculations. Become.

The details of the present invention will be explained below with reference to the drawings.

The drawing is an explanatory diagram showing an embodiment of the steam flow meter according to the present invention, and in the drawing, 1 is a flow rate transmitter, and 2 and 3 are steam piping for transporting saturated steam at a constant pressure from the bottom to the top in the drawing. , the flow rate transmitter 1 includes a direct connection part housing 5 into which the orifice 4 is inserted;
Orifice insertion hole cover 6, metering turbine chamber housing 7, its cover 8, nozzle plate 9, brake turbine chamber housing 10,
Its lid body 11, metering turbine 12, braking turbine 13,
It consists of a rotating main shaft, male magnets 15, 15, and a magnetic sensor 16. Further, 17 is a preamplifier, 18 is an input pulse waveform shaping circuit, 19 is a T-bistable element, 20 is a clock pulse oscillator, 21 is an AND gate, 22 is a pulse counter, 23 is a P-ROM, and 24 is a connecting tube diameter coding circuit. , 25 is an orifice type coding circuit, 26 is a vapor pressure coding circuit to be measured, 27 is a correction coefficient setting device, 28, 29 and 30 is a setting circuit for setting a 3-digit binary coded decimal number M, 31 is a division circuit, 32 is a multiplication circuit,
33 is a flow rate indicator, 34 is a DA converter, and 35 is a flow rate memory meter.

The brake turbine chamber housing 10 defines a brake turbine chamber 10a together with its lid 11, which is filled with water as a brake fluid.

The metering turbine 12 and the braking turbine 13 are connected to the rotating main shaft 14
The braking turbine 13 is connected to a magnet 15,
15 is installed.

Therefore, these turbine chamber casings 7 and 10, as well as the various parts installed inside and outside of them, have the same shape and the same dimensions even if the diameter D of the straight pipe part casing 5 and the opening ratio ψ of the orifice 4 are different. These are commonly used.

The dog portion of the steam flowing in from the steam pipe 2 passes through the orifice 4, but part of it is branched off through the side passage 7b and flows from the nozzle holes 9a, 9a of the nozzle plate 9 to the metering turbine chamber 7a.
It is injected into the interior, causing the metering turbine 12 to rotate together with the braking turbine 13, and then passes through the side channel 7c and joins the main stream downstream of the orifice 4. The rotation of the braking turbine 13 is detected by a magnetic sensor 16, converted into a pulse signal, and sent to the T-bistable element 20 via a preamplifier 17 and a waveform shaping circuit 18.

The clock pulse oscillator 22 oscillates high-frequency clock pulses, and while the T-bistable element 19 is in the set state, the clock pulses are generated by the AND gate 2.
1 and is counted by the pulse counter 22.

The pulse counter 22 is a T-bistable element 19
When is reset, the counted value F is loaded into the division circuit 31 as a divisor and is reset at the same time, so that the counted value F each time is proportional to the oscillation cycle of the flow rate oscillator 1. In other words, the pulse counter 22 is a period counting counter. The P-ROM 23 stores, as data, the numerical values of N corresponding to the addresses specified by the outputs of the address selection circuit, which is composed of a connecting pipe diameter coding circuit, an orifice type coding circuit 25, and a steam pressure coding circuit 26. has been done.

When measuring the weight flow rate, if we ignore the instrumental error of the flow transmitter based on manufacturing errors of each part,
Even if the aperture D of the direct connection part housing 5 and the aperture ratio ψ of the orifice 4 are different, the other members are common and their specifications are fixed, so the meter constant k in equation (2) is equal to the above D. ,ψ
The steam density r is determined by the steam pressure P. Thus, as shown by way of example, each encoding circuit 24, 25 and 26 is connected to four switches 24-1 to 24-4, one switch 25-1 and five switches 26, respectively. -1 to 26-5 and resistors inserted in series with them, respectively, and the respective codes can be defined as shown in Tables 1, 2 and 3.

Therefore, the meter constant KCkg+・m() of the flowmeter is indicated by the 5-bit code Klk2k3k4k5, which is a combination of the straight pipe diameter code and the orifice opening ratio code.
The corresponding numerical value A and the vapor pressure code K6k7k8k9k
The square root of the saturated vapor density r under the pressure corresponding to O [K
A numerical value B proportional to g+・m−b, and their product A−B
always has a 4-digit integer part N, and a formula is established between that N and a correction coefficient M, which will be described later. It is stored in the corresponding address of the P-ROM 19 as a base number.

However, here, C is a unit conversion coefficient. The correction coefficient M is for compensating the deviation of the meter constant k from the reference value based on the manufacturing error of each part of the flow transmitter 1, and can be set as a 3-digit decimal number M. It is set by the setting circuit 27.

Therefore, the value of M is equal to the above-mentioned numerical value A. ．． It is determined in relation to the value of B, etc. If it is found that there is an error Δk in k and it is found that .

The division circuit 31 and the multiplication circuit 32 perform the above operation 7N. M
1'', and the result is displayed on the flow rate indicator 33, and in some cases, converted into analog by the DA converter 34, and indicated and recorded by the flow rate recorder 35.

Since the present invention is constructed as described above, according to the present invention, the receiver consisting of the circuits after the preamplifier 17 is
It can be used regardless of the diameter of the flow transmitter or the orifice opening ratio, and once the meter constant k of the flow transmitter 1 is known, the switch 25 can be used when the orifice is replaced and the opening ratio is changed. -1, and when the steam pressure used changes, the measurement accuracy can be easily maintained by switching the switches 26-1 to 26-5.

Note that the configuration of the present invention is not limited to the above-mentioned embodiments; for example, although a flow rate transmitter is shown here for use in a vertical pipe running from below to above, it may also be applied to a vertical pipe running from above to below. It can also be applied to known flow rate transmitters used in horizontal piping,
can be configured to be controlled by an appropriate digital pressure gauge, etc., and the above-mentioned N, . The method of setting M, the configuration of the encoding circuit, etc. can be freely changed within the scope of the purpose of the present invention, and the present invention encompasses all of them.

[Brief explanation of drawings]

The drawing is an explanatory view showing one embodiment of a steam flow meter according to the present invention. 1...Flow rate transmitter, 4...Orifice,
5... Straight pipe section casing, 7... Metering turbine chamber casing, 9... Nozzle plate, 10... Braking turbine chamber casing, 12... Metering turbine, 13.
... Braking turbine, 14 ... Rotating main shaft, 1
6... Magnetic sensor, 17... Preamplifier, 18... Input pulse waveform shaping circuit, 22...
...Pulse counter, 23...P-ROM12
4... Connecting pipe diameter coding circuit, 25... Orifice type coding circuit, 26... Steam density, etc. coding circuit, 28, 29, 30... M setting circuit, 31... Division circuit, 32... Multiplication circuit, 33... Flow rate indicator.

Claims (1)

[Scope of Claims] 1. A pipe joint that can be connected to a transport pipeline for steam or gas to be measured (hereinafter referred to as steam, etc.), which is connected to the pipe joint,
and a housing having a straight pipe section in the middle into which an orifice with an appropriate opening ratio is inserted, a side passage containing a metering turbine chamber, a braking turbine provided isolated below the metering turbine chamber, and a metering turbine chamber. a metering turbine provided in the metering turbine chamber; a nozzle provided at the inlet of the metering turbine chamber for injecting and rotating steam flowing through a side path to the metering turbine; and a rotary main shaft provided in the braking turbine chamber and penetrating the partition wall to control the metering turbine. a brake turbine coupled to the brake turbine, a brake fluid injected into the brake turbine chamber, a pulse transmitter that detects the rotation of the rotating main shaft and transmits pulses, and a density of steam, etc. that receives the pulses and is measured. A steam flowmeter comprising a display device that performs necessary correction calculations and displays the weight and/or volumetric flow rate of passed steam, etc., where the display device consists of the circuits described in (a) to (i) below. Steam flow meter above. (a) Input pulse waveform shaping circuit. (b) A T-bistable element whose input is the output of the input pulse waveform shaping circuit. (c) Clock pulse oscillator. (d) A gate circuit that allows the output pulse of the clock pulse oscillator to pass only when the T-bistable element is in state 1. (e) A pulse counter that counts the output pulses of the gate circuit. (f) P-ROM. (g) Consisting of a connecting pipe diameter coding circuit, a type coding circuit of the orifice to be used, and a coding circuit for the density of the steam to be measured or a physical quantity that determines the density or is determined by the density; Address selection circuit for the above P-ROM. (h) Digital division circuit capable of calculating the ratio N/F of the output data N of the P-ROM and the count value F of the pulse counter (i) Manually set correction coefficient M and the output value of the digital division circuit A multiplication circuit that calculates and displays the product of N/F. 2. The address selection circuit is a connection pipe diameter coding circuit,
A steam flow meter according to claim 1, comprising an orifice opening ratio encoding circuit and a metered steam pressure encoding circuit.