JPH096427A - Gas governor load simulator - Google Patents

Abstract

PURPOSE: To provide a gas governor load simulator in which a secondary side gas pipeline having various flowability is simulated by the gas of a very small flow rate. CONSTITUTION: The valve displacement Xv of a gas controller piston 15 is detected by a potentiometer 51 and a measurement section 52 measures a secondary gas pressure P2 , they are A/D-converted and outputted to an arithmetic processing section 53. The arithmetic processing section 53 uses a distributed constant model expressing the flowability of a secondary gas pipeline based on the valve displacement Xv and the secondary gas pressure P2 thereby calculating a new secondary gas pressure P2 at an exit of a gas governor including the dynamic process of the secondary gas pipeline. A drive section 54 controls a servo valve 55 based on the secondary gas pressure P2 to provide the output of a desired secondary gas pressure P2 to a chamber 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas governor load simulator, and more particularly to a gas governor load simulator for simulating flow characteristics of a secondary pipe of a gas governor.

[0002]

2. Description of the Related Art Generally, when supplying city gas to ordinary households, buildings, factories, etc., as shown in FIG.
High pressure gas pipeline 42 to which the high pressure gas generated in 1 is delivered
As a main line, a medium-pressure A gas pipeline 43 and a medium-pressure B gas pipeline 44 with gradually lower gas pressure are provided to supply to a building 47, a factory 48, and a low-pressure gas pipeline 45 with a lower gas pressure. It is provided and supplied to a general home 49 or the like. In particular, each gas pipeline is provided with a gas governor 46 for adjusting the pressure of the gas to be supplied to a lower gas pipeline having a low gas pressure for the purpose of stable supply of fluctuations in the demand for the gas.

The gas governor 46 of this type operates by utilizing the gas pressure difference between the primary side (high pressure side) and the secondary side (low pressure side) of the gas governor 46 in order to maintain stable operation even during a power failure. Gas governor is used. FIG. 6 is an explanatory diagram showing the operating principle of the gas governor. The gas governor includes a gas governor body 1 that adjusts a gas supply pressure, that is, a secondary gas pressure P ₂ according to the opening of a valve, and a secondary gas pressure P ₂ and a set spring that uses a primary gas pressure P ₁ as a supply source. Reaction force F
The pilot 2 is configured to generate a driving pressure P _x for adjusting the opening degree of the gas governor main body 1 by the balance with

The pilot 2 uses the supply gas pressure P _s from the primary side gas pressure P ₁ as a supply source and detects the secondary side gas pressure P ₂ while generating a driving pressure P _x according to the set spring reaction force F. It is led to the cylinder lower part 11 of the actuating device 10. Also,
The secondary side gas pressure P ₂ is introduced into the cylinder upper portion 12 of the gas actuating device 10, and the driving pressure P _x , the secondary side gas pressure P ₂ and the internal spring 13 of the gas actuating device 10 are balanced to be in an equilibrium state. The valve opening, that is, the governor opening is determined.

Here, when the secondary gas pressure P ₂ decreases,
The gas pressure in the lower diaphragm chamber 23 of the pilot 2 decreases, the supply side nozzle 21 opens, and the exhaust side nozzle 2
2 is closed and this complementary movement increases the drive pressure P _x with high gain. As a result, the gas manipulator piston 15 is pushed up, the governor opening increases, the gas passage flow rate increases, and the secondary side gas pressure P ₂ rises to the set pressure. On the other hand, when the secondary gas pressure P ₂ rises, the operation is the reverse of the above, the driving pressure P _x drops and the gas manipulator piston 15 is pushed down, and as a result, the governor opening decreases. The gas passage flow rate decreases, and the secondary gas pressure P ₂ decreases to the set pressure.

Conventionally, in a gas governor having such a closed-loop operating characteristic, the operating characteristic of the closed-loop is affected by the load characteristic, that is, the flow characteristic of the secondary side gas pipeline, so that before installation in the actual gas pipeline. In addition, the gas governor load simulator was used to test the operating characteristics of the gas governor. In particular, this type of gas governor load simulator is provided with a pseudo gas pipeline having a predetermined flow characteristic, which is installed in the gas governor as a secondary gas pipeline to actually use gas such as helium. By supplying the gas, the behavior of the gas governor was inspected.

[0007]

Therefore, in such a conventional gas governor load simulator, only a secondary gas pipeline having a flow characteristic with a limited scale that can be arranged as an experimental plant can be simulated. ,
There is a problem in that it is not possible to perform operating characteristics for the secondary gas pipeline that are equivalent to the actual gas governor installation conditions, and a large amount of gas is required during the test depending on the size and installation conditions of the gas governor. It was In particular, for a large-capacity gas governor that is installed in a gas pipeline that supplies a large amount of gas at high pressure, the secondary side gas pipeline has a long mesh shape. Since it is difficult to reproduce in an experimental plant, it was not possible to carry out an accurate operating characteristic test for the gas governor. The present invention is to solve such a problem, and to provide a gas governor load simulator capable of simulating a secondary gas pipeline having various flow characteristics by using a gas with a small flow rate. Has an aim.

[0008]

In order to achieve such an object, a gas governor load simulator according to the present invention comprises a valve displacement detecting means for detecting a valve displacement of a gas operator piston in a gas governor body, and a gas governor outlet. A chamber for holding the secondary side gas pressure, a measuring means for measuring the valve displacement detected by the valve displacement detecting means and the secondary side gas pressure supplied from the chamber, and a flow characteristic of the secondary side gas pipeline. Has a predetermined model that expresses a new model at the outlet of the gas governor including the dynamic process of the secondary gas pipeline from the valve displacement and the secondary gas pressure measured by the measuring means using this model. An arithmetic processing means for calculating the secondary side gas pressure value in real time and a gas pressure control means for controlling the secondary side gas pressure in the chamber based on the calculation output from the arithmetic processing means. It is obtain things. Further, the arithmetic processing means divides the secondary gas pipeline into a plurality of sections in the pipe axis direction as a model expressing the flow characteristics of the secondary gas pipeline, and sequentially calculates the state of each section. It has a model.

[0009]

Therefore, the valve displacement of the gas actuator piston in the main body of the gas governor and the secondary side gas pressure at the gas governor outlet supplied from the chamber are measured by the measuring means, and the predetermined characteristics expressing the flow characteristics of the secondary side gas pipeline are measured. A new secondary side gas pressure value including the dynamic process of the secondary side gas pipeline from the valve displacement and the secondary side gas pressure measured by the measuring means using this model by the arithmetic processing means having the model of Is calculated, and the gas pressure control means controls the secondary side gas pressure in the chamber based on the calculated output from the arithmetic processing means.

[0010]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a gas governor load simulator according to an embodiment of the present invention, in which the same or equivalent parts as those in the above description (see FIG. 6) are designated by the same reference numerals. In FIG. 1, 51 is a gas governor body 1
Valve displacement X _v of the gas actuator piston 15 provided in
Potentiometer (valve displacement detection means) for detecting
Is the output of the potentiometer 51, the primary side gas pressure P ₁ is reduced by the pressure reducing valve 57, and then the supply side nozzle 21 of the pilot 2
Of the supply gas pressure P _s , the secondary side gas pressure P ₂ , and the driving pressure P _x that determines the valve opening of the gas governor body 1, and outputs the measured values after A / D conversion. Part (measuring means).

Reference numeral 53 has a distributed constant model expressing the flow characteristics of the secondary gas line, and the measured gas from the measuring unit 52 is used as a parameter to calculate the secondary gas pressure P ₂ from the distributed constant model.
An arithmetic processing unit (arithmetic processing means) for calculating and outputting in real time, 55 is a servo valve for generating and outputting a predetermined secondary gas pressure P ₂ with the primary gas pressure P ₁ reduced by the pressure reducing valve 58 as an input ( Gas pressure control means), 54 is an arithmetic processing unit 53
The drive unit for driving and controlling the servo valve 55 based on the value of the secondary side gas pressure P ₂ calculated in step 56 has a predetermined capacity,
This chamber stabilizes the secondary gas pressure P ₂ from the servo valve 55.

Next, the operation of the present invention will be described with reference to FIG. The operating principle of the gas governor load simulator according to the present invention is to model the characteristics of the secondary gas line that becomes the load of the gas governor, and to determine the drive pressure P _x and the secondary gas pressure P ₂ detected from the actual gas governor to be tested. Based on this, the secondary side gas pressure P ₂ is calculated in real time by calculation processing by a computer or the like, and this secondary side gas pressure P ₂ is generated and fed back to the governor.

First, compressed air from the air compressor is supplied as the primary side gas pressure P ₁ , reduced in pressure by the pressure reducing valve 57 and supplied as the supply gas pressure P _s to the supply side nozzle 21 of the pilot 2. On the other hand, the secondary side gas pressure P ₂ is supplied from the chamber 56 to the exhaust side nozzle 22 via the lower diaphragm chamber 23 of the pilot 2, and the supply gas pressure P _s and the secondary side gas pressure P ₂ are Secondary gas pressure P
A driving pressure P _x corresponding to the preset spring reaction force F as a target value of ₂ is generated and guided from the pilot 2 to the cylinder lower portion 11 of the gas actuating device 10.

The secondary gas pressure P ₂ is introduced from the chamber 56 into the cylinder upper portion 12 of the gas actuating device 10, and the driving pressure P _x from the pilot 2 and the secondary gas pressure P ₂ are introduced.
₂ and the internal spring 13 of the gas actuating device 10 are in equilibrium, and the gas operating device piston 15 moves up and down to determine the governor opening. Potentiometer 51
Measures the valve displacement X _v due to the vertical movement of the gas operator piston 15 and outputs it to the measuring unit 52.

The measuring section 52 measures the secondary side gas pressure P ₂ supplied to the pilot 2 and the driving pressure P _x output from the pilot 2, and the measurement result and the valve displacement X _v from the potentiometer 51 are measured. It is A / D converted and output to the arithmetic processing unit 53. The arithmetic processing unit 53 calculates a new secondary gas pressure P ₂ according to these measurement results by using a preset distributed parameter model expressing the flow characteristics of the secondary gas pipeline.

Here, a distributed constant model expressing the flow characteristics of the secondary gas pipe will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a distributed constant model,
_{i-2 to} G _{i + 1} are flow rates, u _{i-2 to} u _{i + 1} are flow rates, and P _i-1 to
P _{i + 1} is the gas pressure, W _{i-1 to} W _{i + 1} are the gas masses, ρ _{i- 1}
~ Ρ _{i + 1} is the density of the gas and δ _z is the length of the section.

First, assuming that the flow in the secondary gas pipeline is a one-dimensional flow only in the tube axis direction (z axis direction), the secondary gas pipeline is sectioned along the tube axis with a length δ _z . Split into. Next, numerical analysis is performed by simultaneously connecting the continuity equation, the state equation, the motion equation, and the energy equation in each section. In addition,
Among the respective state quantities, the gas pressure P, the gas density ρ, the gas mass W and the gas temperature θ are the average values in each section, and the flow velocity u is the cross sectional area at each position of the pipeline. Use the average value.

Here, assuming that the state change in the pipeline is an isothermal change, each basic equation is discretized in the pipeline section shown in FIG.
First, assuming that the cross-sectional area of the pipeline is A, and the mass W and the flow rate G are W = ρAδ _z G = ρAu in the following equation 4, the continuous equation:

[0019]

[Equation 1]

Equation of state:

[0021]

[Equation 2]

Equation of motion:

[0023]

(Equation 3)

It is expressed as Here, the viscous resistance f is given by
The calculation is performed using the Darcy-Weisbach formula represented by the formula below.

[0025]

(Equation 4)

As an empirical rule, the pipe friction coefficient λ is a function of the Reynolds number Re shown in the equation (5).

[0027]

(Equation 5)

The Reynolds number Re is expressed by the equation (6).

[0029]

(Equation 6)

Here, the kinematic viscosity μ _i is obtained by the equation of the Sutherland's shown by the equation (7).

[0031]

(Equation 7)

At the inlet of the pipeline, the gas flow rate flowing into the gas pipeline is determined from the displacement of the gas governor, as shown in the equation (8). Gas flow rate:

[0033]

(Equation 8)

The arithmetic processing unit 53 can calculate each state in the secondary side pipe line portion by sequentially calculating these equations in real time. First, the arithmetic processing unit 53
Is the diameter of the gas governor, the valve diameter, and the flow rate characteristic that is measured and set in advance as shown in FIG.
_v based on such relationship between the governor capacity coefficient CV, a valve displacement X _v of the gas manipulator piston 15 from the measuring section 52 with deriving a governor capacity coefficient CV, the governor capacity coefficient CV, from the measuring unit 52 From the secondary gas pressure P ₂ and the primary gas pressure P ₁ which is fixedly set in advance,
The flow rate G is derived.

[0035]

[Equation 9]

Subsequently, the flow rate G supplied from the gas governor thus obtained and the secondary side gas pressure P from the measuring unit 52 are obtained.
Based on ₂ and above, a new secondary gas pressure P at the gas governor outlet including the dynamic process of the secondary gas pipeline is used by using the distributed constant model expressing the flow characteristics of the secondary gas pipeline described above. Calculate ₂ . FIG. 4 is a block diagram showing a distributed constant model of the secondary gas pipeline. In the figure, 32 to 3n are blocks for calculating the flow rate G and the gas pressure P in each section provided by dividing the secondary side gas pipeline into n-1 pieces, and correspond to the section closest to the gas governor outlet. The blocks are sequentially connected in series from the block 32 in correspondence with each section.

Reference numeral 32a is a block for calculating the gas pressure in the section based on the above-mentioned equation of state (see equation 2), which is calculated from the difference between the flow rate G _{1 of} gas flowing into the section and the flow rate G _{2 of} gas flowing out of the section. The gas pressure P ₂ in the section is calculated. Further, 32b is a block for calculating the flow rate flowing out from the section based on the above-mentioned equation of motion (see Formula 3), and flows out from the section from the difference between the gas pressure P ₂ in the section and the gas pressure P _{3 in the} next section. The gas flow rate G ₂ is calculated.

On the other hand, reference numeral 32c is a block for compensating for the temperature of the gas in the section, which changes according to the flow rate flowing into the section, and is calculated from the difference between the flow rate G _{1 of the} gas flowing into the section and the flow rate G _{2 of the} gas flowing out of the section. The temperature θ ₂ of the gas in the section is calculated. The temperature compensation amount in the block 32c is small and may be omitted, but the gas pressure P ₂ can be calculated more accurately. In addition, these blocks 32a
32c are similarly provided in all the blocks 32-3n corresponding to each section.

In FIG. 4, V ₂ is the capacity of the section,
θ ₂ is the gas temperature in the section, W ₂ is the gas mass in the section, ρ
₂ is the relative density of the gas. R is the gas constant, θ _a
Is the atmospheric temperature, Cv is the constant volume specific heat, S is the heat transfer area, h is the heat transfer coefficient, A is the pipe cross-sectional area, D is the pipe diameter, and λ is the pipe friction coefficient.

In this way, the secondary gas pressure P ₂ at the governor outlet is successively calculated in real time at a predetermined timing in the arithmetic processing unit 53 and output to the drive unit 54. The drive unit 54 D / A converts the secondary gas pressure P ₂ value from the arithmetic processing unit 53, and drives the servo valve 55 by the obtained signal. In response to this, the servo valve 55 turns the primary side gas pressure P
_The gas pressure supplied from ₁ via the pressure reducing valve 58 is controlled,
A desired secondary gas pressure P ₂ is output to the chamber 56.

As a result, the gas pressure in the chamber 56, that is, the secondary gas pressure P ₂ is fed back to the pilot 2 and the cylinder upper portion 12 of the gas actuating device 10. Furthermore, the valve opening of the gas manipulator piston 15 in response to changes in the secondary gas pressure P ₂ is controlled, the behavior of such a gas governor is detected as described above, sequentially latest secondary The side gas pressure P ₂ is calculated and supplied to each part.

As described above, the actual gas governor is used, the potentiometer 51 for measuring the valve displacement X _v of the gas actuator piston 15 is provided, and the measurement is carried out by the measuring section 52 together with the secondary side gas pressure P _2. According to the result, the calculation processing unit 53 calculates a new secondary gas pressure P ₂ by using the model of the secondary gas pipeline, and based on this value, the servo valve 55 is driven and controlled to drive the secondary gas. Since the gas pressure P ₂ is controlled, it is possible to test the operating characteristics with a slight flow rate consumed by the pilot 2 and the servo valve 55.

By changing the model of the secondary gas pipeline, it becomes possible to simulate secondary gas pipelines having various flow characteristics. Furthermore, as a model of the secondary gas pipeline, the secondary gas pipeline was divided into multiple sections along the pipe axis direction, and a distributed constant model was used to calculate the state of each section. It is possible to more accurately simulate the flow characteristics of the side gas pipeline.

In the above description, the primary side gas pressure P ₁ , the supply gas pressure P _s , and the set spring reaction force F of the pilot 2 are set.
However, the load can be simulated under various operating conditions by changing the setting by the arithmetic processing unit 53 or the pilot 2 as described above. Further, in FIG. 1, the measuring unit 52 also measures the supply gas pressure P _s and the driving gas pressure P _x, but this is the arithmetic processing unit 53.
Is for checking the behavior of the pilot 2 in detail, and is not particularly necessary.

[0045]

As described above, according to the present invention, the valve displacement detecting means for detecting the valve displacement of the gas operator piston in the gas governor body, the chamber for holding the secondary side gas pressure at the gas governor outlet, A calculation having a predetermined model expressing the flow characteristic of the secondary gas pipeline by providing a valve displacement detected by the valve displacement detection means and a measuring means for measuring the secondary gas pressure supplied from the chamber. By the processing means, from the valve displacement and the secondary side gas pressure measured by the measuring means, a new secondary side gas pressure value at the gas governor outlet including the dynamic process of the secondary side gas pipeline is calculated in real time, Since the gas pressure control means controls the secondary side gas pressure in the chamber based on the calculated output,
It is possible to simulate the secondary side gas pipeline with a small flow rate consumed by the gas pressure control means, etc. without flowing the actual flow rate to the gas governor body. It is possible to test the operating characteristics with a long pipeline as a load.

Further, as a model of the flow characteristic of the secondary side gas pipeline of the arithmetic processing means, the secondary side gas pipeline is divided into a plurality of sections in the pipe axis direction, and the state of each section is sequentially calculated. Since the distributed constant model is used, the resistance-capacitance method that approximates the resistance-capacitance system assuming that the conduit has a constant capacity, and the effective cross section in which the conduit is replaced by the effective area of one throttle and the volume connected to it It is possible to express the flow characteristics of the secondary gas pipeline more precisely than the conventional pipeline model such as the method.

[Brief description of drawings]

FIG. 1 is a block diagram of a gas governor load simulator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a distributed constant model.

FIG. 3 is an explanatory diagram showing a flow rate characteristic of a gas governor.

FIG. 4 is a block diagram showing a distributed constant model of a secondary gas pipeline.

FIG. 5 is an explanatory diagram showing a city gas supply system.

FIG. 6 is an explanatory diagram showing the operation of the gas governor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas governor main body, 10 ... Gas operation device, 11 ... Cylinder lower part, 12 ... Cylinder upper part, 13 ... Internal spring, 1
5 ... Gas operation device piston, 2 ... Pilot, 21 ... Supply side nozzle, 22 ... Exhaust side nozzle, 51 ... Potentiometer (valve displacement detecting means), 52 ... Measuring part (measuring means), 5
3 ... Arithmetic processing section (arithmetic processing means), 54 ... Driving section, 55
... Servo valve (gas pressure control means), 56 ... Chamber, P
₁ ... primary gas pressure, P ₂ ... secondary gas pressure, P _s ... feed gas pressure, P _x ... driving pressure, X _v ... valve displacement.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Otani 4-1-1 Omagari, Samukawa-cho, Takaza-gun, Kanagawa Yamatake Honeywell Co., Ltd. Shonan Factory

Claims (2)

[Claims] 1. A gas governor load simulator for simulating a secondary gas pipeline connected to a self-powered gas governor having a closed-loop operating characteristic, wherein a valve displacement detecting means for detecting a valve displacement of a gas operator piston in a gas governor body. A chamber for holding the secondary side gas pressure at the gas governor outlet, a measuring means for measuring the valve displacement detected by the valve displacement detecting means and the secondary side gas pressure supplied from the chamber, and the secondary side gas A gas governor outlet including a dynamic process of the secondary side gas pipeline based on the valve displacement and the secondary side gas pressure measured by measuring means using this model, which has a predetermined model expressing the flow characteristics of the pipeline. In the chamber based on the calculation output from the calculation processing means for calculating a new secondary side gas pressure value in real time. Gas governor load simulator, characterized in that it comprises a gas pressure control means for controlling the following-side gas pressure. 2. The gas governor load simulator according to claim 1, wherein the arithmetic processing means defines the secondary side gas pipeline in a plurality of sections in the axial direction as a model expressing the flow characteristics of the secondary side gas pipeline. A gas governor load simulator characterized by having a distributed constant model for dividing and sequentially calculating the state of each section.