Measurement of the differential pressure of liquid metals

• US 3,902,369 A
• Filed: 05/02/1974
• Issued: 09/02/1975
• Est. Priority Date: 05/02/1974
• Status: Expired due to Term

• Current Assignee: Hugh J. Metz
• Original Assignee: Hugh J. Metz
• Inventors: Metz, Hugh J.
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US05/466,347
• Time in Patent Office: 488 Days
• Field of Search: 73/398R,398C,398AR,25R,152,388 417/50
• US Class Current: 73/753
• CPC Class Codes: G01L 11/00 Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00

Abstract

The flow of liquid metal in a pipe is opposed by a magnetic-type liquid metal pump until there is almost zero flow shown by a magnetic-type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of hightemperature bellows or diaphragm seals, and a magnetic-type liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed.

Claims

1. A system for measuring the differential pressure of a process flowing coolant stream of liquid metals between a high-pressure point and a low-pressure point in said flowing stream comprising a pipe connected between said points, said pipe somewhere in its length accommodating a permanent magnet pump, a variable speed motor coupled to said pump for operating the pump such as to oppose the liquid metal pressure from said stream, an indicating means coupled to said pipe between said pump and said lowpressure point, means for regulating the speed of said motor until said indicating means provides a near-zero reading, and a count rate indicator coupled to said motor to provide an indication of the speed of said motor and when said indicating means reaches said near-zero reading then said motor speed indication thus provides an indication proportional to said differential pressure existing between said points.

2. The system set forth in claim 1, wherein said indicating means coupled to said pipe is a magnetic flowmeter, and said means for regulating the speed of said pump motor includes a head control unit coupled between said flowmeter output and said motor to regulate the motor speed to provide said near-zero reading on said flowmeter indicating means and thus a near-zero liquid metaL flow through said loop while at the same time said count rate indicator is providing said differential pressure indication.

3. The system set forth in claim 1, wherein said indicating means coupled to said pipe is a differential pressure transducer, one side of said transducer and said pump being connected to said high-pressure point by means of a first high-temperature seal and the other side of said transducer being connected to said lowpressure point by means of a second high-temperature seal, said transducer adapted to be utilized to measure said differential pressure directly while said pump motor is not operating, said pump adapted selectively to be operated in one direction while said process stream is shut down for calibrating said transducer and to be operated in a reverse direction to oppose the pressure of said process stream when it is not shut down such that an independent check of the process differential pressure can be obtained when said transducer shows a zero differential pressure at which time the process differential pressure is inferred from the motor pump speed as provided by said count rate indicator, said pipe between said first high-temperature seal and said one side of said transducer containing a liquid metal for insuring proper operation of said pump during its use.

4. The system set forth in claim 3, wherein said process flowing coolant stream consists of a molten salt instead of liquid metals.