Pump control system

• US 20030063978A1
• Filed: 07/18/2002
• Published: 04/03/2003
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Asahi Kogyosha Company Limited, Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: Takahashi, Hiroshi, Tani, Keisuke, Yoshida, Shigehiro, Kosaka, Hiromichi
• Granted Patent: US 6,939,109 B2
• Time in Patent Office: Days
• US Class Current: 417/3
• CPC Class Codes: F04B 2203/0214 Number of working motor-pump units
• CPC Class Codes: F04B 2205/09 Flow through the pump
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04D 13/14 the pumps being all of centrifugal type deviation valves F04D15/0016
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0209 responsive to a condition of the working fluid F04D15/029 takes precedence
• CPC Class Codes: F04D 15/029 for pumps operating in parallel
• CPC Class Codes: F25B 2600/13 Pump speed control
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

The present invention provides a system which comprises primary supply pumps and secondary supply pumps and controls pressurized water supply systems, air-conditioning systems, or the like that supply chilled water or hot water using these pumps. In the present invention, calculation is carried out based on measurement signals obtained by measuring pressure, flow rate, open rate of valves, etc. by providing sensors in supply channels.

Claims

1. A pump control system used for pressurized water supply systems and provided with

primary supply pumps that supply chilled water or hot water from a return header to a primary supply header via refrigerators, heat pump chillers, or boilers,

secondary supply pumps that are provided with inverters and supply chilled water or hot water from said primary supply header to a secondary supply header,

a flow sensor that measures the flow from said secondary supply header to said return header, and

a pressure difference sensor that measures the pressure difference between said secondary supply header and said return header,

further comprising a secondary pump controller that determines a supply pressure from the secondary supply pumps using a flow rate measured with said flow sensor, carries out prescribed calculations based on this supply pressure and a discharge pressure measured with said pressure difference sensor, and outputs a control signal corresponding to the calculated result to said inverters.

2. A pump control system in accordance with claim 1, wherein said secondary pump controller determines the supply pressure from the secondary supply pumps by substituting a flow rate value measured with said flow sensor for the formula containing the flow rate as a variable.

3. A pump control system in accordance with claim 1, wherein said secondary pump controller outputs the rotational frequency control signal corresponding to the result of calculation to said inverters.

9. A pump control system in accordance with any of claims 1 to 8, wherein a secondary pump controller is provided which contains an input-output processing portion that determines said inverter rotational frequency so that the discharge pressure from said secondary supply header is a prescribed constant discharge pressure for a prescribed period from the start of operation.

10. A pump control system in accordance with any of claims 1 to 9, wherein a secondary pump controller is provided which contains an input output processing portion that determines said inverter rotational frequency so that the discharge pressure from said secondary supply header is increased by a prescribed value for a prescribed period at every prescribed time interval.

11. A pump control system in accordance with any of claims 4 to 10, wherein a monitor signal input portion that inputs monitor input signals into said input-output processing portion, a monitor display portion and a data memory portion are provided.

12. A pump control system in accordance with any of claims 1 to 11, comprising an operation display portion that is provided in said secondary pump controller and displays the operating status.

13. A pump control system in accordance with any of claims 1 to 12, comprising a primary external communication portion that is provided in said secondary pump controller and displays the operating status in a remote place via the remote communication means.

14. A pump control system in accordance with any of claims 1 to 13, comprising a secondary external communication portion that is provided in said secondary pump controller and changes the settings of parameters necessary for operation from a remote place via the external communication means.

4. A pump control system used for pressurized water supply systems and provided with

primary supply pumps that supply chilled water or hot water from a return header to a primary supply header via refrigerators, heat pump chillers, or boilers,

secondary supply pumps that are provided with inverters and supply chilled water or hot water from said primary supply header to a secondary supply header,

a flow sensor that measures the flow from said secondary supply header to said return header, and

a pressure difference sensor that measures the pressure difference between said secondary supply header and said return header,

further comprising a secondary pump controller that contains an input-output processing portion which determines said inverter rotational frequency by performing calculations, based on said discharge pressure measured with said pressure difference sensor and a supply pressure calculated by selecting the fixed resistance K0 of the entire system, pipeline constants K1 and K2, and a constant n determined using the formula of head of friction loss using a signal obtained by the measurement with said flow sensor and an external input signal or using tables in the data storage portion.

5. A pump control system in accordance with claim 4, wherein the outside air temperature input signal is used as said external input signal.

6. A pump control system in accordance with claim 4, wherein the seasonal change input signal is used as said external input signal.

7. A pump control system in accordance with claim 4, wherein the load change input signal is used as said external input signal.

8. A pump control system in accordance with claim 7, wherein the load availability factor change input signal is used as said load change input signal.

15. A pump control system used for air-conditioning systems and provided with

primary supply pumps that supply chilled water or hot water from a return header to a primary supply header via refrigerators, heat pump chillers, or boilers,

secondary supply pumps that are provided with inverters and supply chilled water or hot water from said primary supply header to a secondary supply header,

two-way type control valves provided between said secondary supply header and said return header, and

a pressure difference sensor that measures the differential pressure of chilled water or hot water between said secondary supply header and said return header,

further comprising a secondary pump controller containing an input-output processing portion that controls the rotational frequency of said inverters using an open rate signal from said two-way type control valves and a signal obtained by measurement with said pressure difference sensor.

16. A pump control system in accordance with claim 15, wherein a monitor signal input portion that inputs monitor input signals into said input-output processing portion, a monitor display portion and a data memory portion are provided.

17. A pump control system in accordance with claim 15 or claim 16, comprising an operation display portion that is provided in said secondary pump controller and displays the operating status.

18. A pump control system in accordance with any of claims 15 to 17, comprising a primary external communication portion that is provided in said secondary pump controller and displays the operating status in a remote place via the remote communication means.

19. A pump control system in accordance with any of claims 15 to 18, comprising a secondary external communication portion that is provided in said secondary pump controller and changes the settings of parameters necessary for operation from a remote place via the external communication means.