System for controlling flow rate in pipelines

• US 4,180,083 A
• Filed: 10/18/1977
• Issued: 12/25/1979
• Est. Priority Date: 10/20/1976
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Matsumoto, Kuniaki, Miyaoka, Shinichiro, Hatakeyama, Junichi
• Primary Examiner(s): Cline, William R.
• Application Number:
  US05/843,253
• Time in Patent Office: 798 Days
• Field of Search: 137/101.25, 137/236, 137/255, 137/256, 137/386, 137/391, 137/565, 137/566, 137/567, 137/571, 405/52, 405/53, 417/36, 210/104, 210/262
• US Class Current: 137/101.25
• CPC Class Codes: H02J 15/003 in the form of hydraulic energy
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y10T 137/2534 Liquid level response
• CPC Class Codes: Y10T 137/4673 Plural tanks or compartments with parallel flow
• CPC Class Codes: Y10T 137/7287 Liquid level responsive or maintaining systems
• CPC Class Codes: Y10T 137/85986 Pumped fluid control
• CPC Class Codes: Y10T 137/86187 Plural tanks or compartments connected for serial flow

Abstract

System for controlling flow rate in pipelines connecting a plurality of reservoirs is disclosed. Flow rate Q_ij (t) of fluid flowing from one reservoir (i) to another reservoir (j) is first calculated from the water levels H_i (t), H_j (t) of both reservoirs (i), (j) and then water level H_j (t+1) of the reservoir (j) at the time (t+1) is calculated from its inflow and outflow taking into account the predicted amount of demand Q_je (t).

If the water level h_j (t+1) is below or over the predetermined lower or upper limitation, manipulated variables for valves and pumps installed in pipelines are regulated to control inflow of the reservoir (j) so that the required fluid-feed is satisfied while maintaining the scheduled water level of the reservoir (j).

Claims

1. A system having pipelines, a plurality of reservoirs and means for controlling the flow of fluid through said pipelines to, from, and between said plurality of reservoirs, comprising:

valves and pumps installed in the pipelines for regulating the flow rate of fluid passing therethrough;

first means for calculating the amount of predicted water demand Q_je (t) which is supplied from any reservoir (j) to consummers and for producing an output signal representative thereof;

second means operatively associated with said first means for calculating flow rate Q_ij (t) changing with time (t) of fluid flowing in a pipeline from a reservoir (i) to a reservoir (j), from fluid level H_i (t), H_j (t);

third means operatively associated with said first and second means for calculating fluid level H(t+1) at the time (t+1) of the reservoir (j) from the predicted demand Q_je (t) received from the first means, the amounts of inflow Q_ij (t) and outflow Q_j (t) thereof and the water level H_j (t) at the time (t) of the reservoir (j); and

fourth means operatively associated with said first, second, and third means for controlling manipulatable variables of the pumps and valves when the water level H_j (t+1) thus obtained is below a predetermined lower limitation LH_j or over an upper limitation UH_j so as to keep actual levels of fluid within said reservoirs between predetermined levels.

2. Controlling system according to claim 1, comprising a digital computer, said computer constituting a combination of the first, second and third means.

3. System according to claim 1, which further comprises, in operative association with the first through fourth means, means for measuring both the actual fluid level H_j (t) and the amount of the actual fluid demand Q_je (t);

and correction means for correcting the calculated fluid level of the reservoir (j) and predicted fluid demand on the basis of the values thus actually measured.

4. System according to claim 3, wherein said correction means comprises means for obtaining a corrected value, Q_j (t) of fluid demand from the following equation:

space="preserve" listing-type="equation">Q.sub.j (t)=Q.sub.j (t) (qj(t.sub.0)/Q.sub.j (t.sub.0)) (t=t.sub.0, t.sub.0 +1, - - - )

where

qj(t) is measured demand and

Q_j (t) predicted demand.

5. The system according to claim 3, wherein said correction means includes means for correcting the calculated reservoir fluid level value H(t) when,

6. System according to claim 5, wherein said third means includes means for obtaining a predicted fluid level at the time (t₀ +N) from the following equation, ##EQU8##

7. System according to claim 6, wherein said correction means includes means for correcting the flow rate Q_ij (t) when the fluid level H_j (t₀ +N) becomes smaller than the lower limitation LH_j or larger than the upper limitation UH_j.

8. System according to claim 1, wherein said third means includes means for obtaining the water level H_j (t+1) from the following equation:

space="preserve" listing-type="equation">H.sub.j (t+1)=H.sub.j (t)+(Q.sub.ij (t)-Q.sub.je (t)-Q.sub.j (t))/S.sub.j.

9. System according to claim 1, wherein said third means includes means for obtaining the flow rate Q_ij (t) from an equation of the condition of fluid pressure balance.

10. A system having pipelines, a plurality of reservoirs and means for controlling the flow through said pipelines to, from and between said plurality of reservoirs, comprising:

flow regulating means installed in operative relationship to said pipelines for regulating the flow of fluid passing therethrough;

level detecting means mounted in association with said reservoirs for detecting the levels of fluid therein and generating outputs representative thereof;

flow rate detecting means mounted in association with said pipelines for detecting the flow rates therethrough, and for generating an output representative thereof;

first control means for predicting demand for said fluid and for generating an output representative thereof;

second control means for receiving an output from said first control means and determining a flow rate location schedule including scheduled flow rates in said pipelines and water levels in said reservoirs;

third control means for correction of said scheduled flow rates and water levels in response to the output from said level and flow rate detecting means when said detected flow rates and levels deviate from said scheduled rates and levels by a predetermined amount; and

fourth control means for operating said flow regulating means so as to control the flow rates and reservoir levels in accordance with said corrected scheduled flow rates and reservoir levels.

11. A system according to claim 10, comprising a digital computer, said computer constituting a combination of said first, second and third control means.