JP3412940B2 - Microcomputer meter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer meter for estimating the pressure of a main gas such as gas.

[0002]

2. Description of the Related Art As a device for estimating the pressure of gas or the like in a main pipe, there is a pressure estimating device described in JP-A-6-186107. FIG. 3 shows an outline of this pressure estimating device. In FIG. 3, 101 is a main pipe and 103 is a customer. A gas microcomputer meter 10 for the customer 103
5, the measurement terminal device 107, the pressure sensor 109, and the gas appliance 111 are installed. The gas microcomputer meter 105 and the main pipe 101 are connected by a pipe 113a, and the gas microcomputer meter 105 and the gas appliance 111 are connected by a pipe 113b.

The gas microcomputer meter 105 is a main pipe 101.
The integrated flow rate of the gas supplied to the consumer 103 through the pipe 113a is measured. The measurement terminal device 107 measures and stores the instantaneous gas flow rate Q using the output value of the gas microcomputer meter 105 at a predetermined time interval. Further, the pressure measured by the pressure sensor 109 is read. The pressure sensor 109 detects the pressure P ₁ in the pipe 113b and sends it to the measurement terminal device 107.

The measuring terminal device 7 has the main pipe 10 based on the instantaneous flow rate Q and the pressure P ₁ sent from the pressure sensor 109.
The pressure P ₀ of 1 is estimated according to the following equation.

P ₀ = P ₁ + αQ ² + h (1) where h: pressure loss α: flow coefficient α = S · L / (K ² · D ⁵ ) S: gas specific gravity L: main pipe 101 to pressure sensor Pipe length up to 109 K: Coefficient D: Pipe diameter

[0006]

However, in such a pressure estimation device, the measurement terminal device 107 and the pressure sensor 109 must be installed in the gas microcomputer meter 105, which increases the cost. Further, the flow rate measured by the gas microcomputer meter 105 is an integrated flow rate, and since this integrated flow rate is converted into an instantaneous flow rate Q, there is no simultaneity between the instantaneous flow rate Q and the pressure P ₁ measured by the pressure sensor 109. There is a problem that the accuracy of the applied pressure P ₀ is low.

The equation (1) is an equation for an ideal straight pipe, and if there is a bend in the pipes 113a and 113b, the estimation accuracy is lowered. In addition, due to aging, the piping 113a, 1
When the inside of 13b is contaminated and a part thereof is clogged, the value of the flow coefficient α changes, and the estimation accuracy decreases.

The present invention has been made in view of such a problem, and an object thereof is to provide a microcomputer meter capable of estimating the pressure P _{0 of the} main pipe 101 with high accuracy and at low cost. is there.

[0009]

In order to achieve the above-mentioned object, the present invention is connected to a main pipe through a pipe,
A microcomputer meter for estimating a pressure P ₀ of a fluid to be measured flowing through the main pipe, a pressure measuring means for measuring a pressure P ₁ of the measuring object, a flow rate measuring means for measuring an instantaneous flow rate Q of the measuring object, and Q. If ≦ β, P ₀ = P ₁ , and if Q> β, P
₀ is a microcomputer meter characterized by including a means for estimating the pressure P ₀ as being unmeasurable (where β is a constant).

[0010]

In the present invention, the pressure P ₁ to be measured is measured, and the instantaneous flow rate Q to be measured is measured. If Q ≦ β, P ₀ =
If P ₁ and Q> β, P ₀ cannot be measured (however, β: constant)
As a result, the pressure P ₀ is estimated.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram showing a main pipe 1 and a customer 3 according to an embodiment of the present invention.

In FIG. 1, 1 is a main pipe and 3 is a consumer. A gas microcomputer meter 5 and a gas appliance 7 are installed in the customer 3, and the gas microcomputer meter 5 and the main pipe 1 are connected to a pipe 9a.
And the gas microcomputer meter 5 and the gas appliance 7 are connected by the pipe 9b. The gas microcomputer meter 5 can communicate with gas microcomputer meters of other consumers.

FIG. 2 is a schematic configuration diagram of the gas microcomputer meter 5. The gas microcomputer meter 5 has a CPU 11, a memory 13, a pressure sensor 15, and a flow rate sensor 17. The pressure sensor 15 measures the pressure P _{1 of the} pipe 9a. The flow rate sensor 17 measures the flow rate Q of the gas in the pipe 9a. CPU
Reference numeral 11 estimates the pressure in the main pipe 1 as follows based on the pressure P ₁ and the flow rate Q sent from the pressure sensor 15 and the flow rate sensor 17.

In the case of Q ≦ β, (β: constant) P ₀ = P _{1 In} the case of Q> β, P ₀ cannot be measured. However, β is a value of a small flow rate at which the pressure loss of the pipe can be ignored. , Β are stored in the memory 13 in advance.
The memory 13 stores the estimated pressure P ₀ . According to the present embodiment, although there is a possibility that measurement may not be possible, the measured pressure and flow rate are simultaneous, and the pressure P _{0 of the} main pipe 1 can be measured with extremely high accuracy. In addition, the estimation accuracy does not decrease due to aging.

In the case of Q> β, the gas microcomputer meter 5 communicates with the adjacent gas microcomputer meter, and the pressure P ₀ independently estimated by the adjacent gas microcomputer meter is regarded as the pressure P ₀ estimated by itself. By doing so, it is possible to eliminate the possibility that the estimation cannot be performed. In addition, although each of the above-described embodiments describes the gas, the present invention can be applied to water supply and the like.

[0016]

As described above in detail, according to the present invention, the pressure P ₀ of the main pipe can be estimated with high accuracy and at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a main pipe 1 and a customer 3 according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a gas microcomputer meter 5.

FIG. 3 is a schematic configuration diagram of a conventional pressure estimation device.

[Explanation of symbols]

1 ... Main 3 ... Customer 5 ……… Gas microcomputer meter 7 ... Gas appliances 9a, 9b ......... Piping 11 ... CPU 13 ......... Memory 15 ... Pressure sensor 17 ......... Flow rate sensor

Claims (4)

(57) [Claims] 1. A microcomputer meter connected to a main pipe via a pipe for estimating a pressure P ₀ of a fluid to be measured flowing through the main pipe, the pressure measuring means measuring a pressure P _{1 of the} measurement target. And a flow rate measuring means for measuring the instantaneous flow rate Q of the object to be measured; if Q ≦ β, then P ₀ = P _{1 If} Q> β, P ₀ cannot be measured (however, β: constant), and the pressure P ₀ is estimated. A microcomputer meter characterized by comprising: 2. A microcomputer meter connected to the main pipe through a pipe for estimating the pressure P ₀ of a fluid to be measured flowing through the main pipe, the pressure measuring means measuring the pressure P _{1 of the} measurement target. And a flow rate measuring means for measuring the instantaneous flow rate Q of the measurement object, and if Q ≦ β, P ₀ = P ₁ (where β is a constant) and if Q> β, communicate with an adjacent micom meter to approach. the pressure P ₀ the microcomputer meter has its own estimation, the pressure P ₀ which is his estimated, the microcomputer meter, characterized by comprising means for estimating the pressure P _0, the. 3. The microcomputer meter according to claim 1, wherein the measurement target is gas. 4. The microcomputer meter according to claim 1, wherein the measurement target is water.