公开(公告)号：US3420092A

公开(公告)日：1969-01-07

申请号：US3420092D

申请日：1966-02-21

Applicant: BASF AG

Inventor： DORSCH DIETER

IPC: G01L9/00 ,  G01N9/00

CPC classification number: G01N9/002 ,  G01L9/0008

公开(公告)号：CA827397A

公开(公告)日：1969-11-18

申请号：CA827397D

Applicant: BASF AG

Inventor： DORSCH DIETER

公开(公告)号：FR1445512A

公开(公告)日：1966-07-15

申请号：FR10992

申请日：1965-03-27

Applicant: BASF AG

Inventor： DORSCH DIETER

IPC: G01N9/00

公开(公告)号：CA600418A

公开(公告)日：1960-06-21

申请号：CA600418D

Applicant: BASF AG

Inventor： PLATZ ROLF ,  KROEPER HUGO ,  DORSCH DIETER

公开(公告)号：GB1095257A

公开(公告)日：1967-12-13

申请号：GB1285965

申请日：1965-03-26

Applicant: BASF AG

Inventor： DORSCH DIETER

IPC: G01G19/00 ,  G01N9/00

Abstract: 1,095,257. Measuring specific gravity electrically. BADISCHE ANILIN - & SODAFABRIK A. G. March 26, 1965 [March 28, 1964], No.12859/65. Heading G1N. The specific gravity or density of a gas is determined by measuring the frequency of vibration of an electrically maintained tuning fork exposed to the gas. It is stated that the frequency is independent of the composition and viscosity of the gas. As shown, Fig. 9, the measuring head comprises a tuning fork 1 mounted inside a pressure pipe 2 by means of a tapered shank 3 held in place by threaded ring 6. The tuning fork is electrically maintained by electromagnets 10 and 11 and amplifier 12. The output of the amplifier is mixed with a constant frequency signal provided by crystal controlled oscillator 15 and frequency divider 16, and the difference frequency is selected by low pass filter 18 and measured by frequency meter 20. The electromagnets 10, 11 each comprise a pair of ferromagnetic polepieces (8), Figs. 1 and 2 (not shown), surrounded by coils and bridged by permanent magnets (9). The polepieces (8) are welded into apertures in the pipe 2 which is made of low permeability steel. The tines of the tuning fork have heads (7) shaped to correspond to the internal surface of pipe (2), and may also have one or more baffle plates (13, 14), Figs. 5 to 8 (not shown), of aluminium or titanium alloy to increase the variation of frequency with specific gravity. The measuring head (21) may be mounted on a by-pass tube, Fig. 11 (not shown), or directly on the main duct (24) using a Pitot tube (23) to ensure that the head (21) is always flushed with gas, Fig. 12 (not shown).