Measuring assembly for studying gaseous media

• US 5,571,947 A
• Filed: 05/08/1995
• Issued: 11/05/1996
• Est. Priority Date: 05/20/1994
• Status: Expired due to Term

• Current Assignee: Testo GmbH Y Co.
• Original Assignee: Testo GmbH & Company
• Inventors: Senn, J urgen, Strnad, Kurt
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): WIGGINS, JOHN DAVID
• Application Number:
  US08/436,149
• Time in Patent Office: 547 Days
• Field of Search: 73/31.05, 73/23.2, 422/83, 422/94, 422/99, 422/102, 422/104, 422/49
• US Class Current: 73/31.05
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment devices for withdrawing samples in the gaseous state G01N1/22

Abstract

A measuring assembly is described for studying gaseous media, in which a measuring cell (20) connected to a circuit board (40) is clamped into a receptacle (10). The receptacle (10) includes a base plate (11), a pressure plate (30), arms connecting base plate (11) and the pressure plate (30) with each other, i.e., a stud bolt (13) and a connecting arm (14), as well as a pressure spring (16) acting on the pressure plate (30). The pressure plate (11) is supplemented by a chamber cover (15) so as to form a gas chamber (17). Preferably, a filter (50) is located between the base plate (11)/chamber cover (15) and the measuring cell (20).

Claims

1. A measuring assembly for sensing gaseous media, comprising:

a) an electrical measuring cell having an inlet opening for introducing gas thereto and an outlet for dismissing gas therefrom for generating electrical signals in accordance with the concentration and/or composition of the gaseous medium introduced to said measuring cell;

b) a signal processing circuit connected to said measuring cell for receiving and evaluating said electrical signals, said circuit being arranged on a circuit board;

c) a receptacle including a base plate and a cover plate between which said measuring cell is located;

d) means for electrically and mechanically connecting said circuit board to the said measuring cell in a releasable manner so that said measuring cell with said circuit board is disposed between said base plate and said cover plate whereby said measuring cell may be readily replaced with another;

e) said cover plate comprising a pressure plate constructed to press said measuring cell against said base plate with a uniform pressure distribution; and

f) a pressure spring connected in a retaining position to said receptacle to abut an adjacent surface of said pressure plate and to impose a defined tension on a said pressure plate and movable from said retaining position to permit the replacement of said measuring cell.

2. The measuring assembly as claimed in claim 1, wherein there is further included a first connecting arm having a first end connected rigidly to said base plate and a second end connected to a ring groove, a second connecting arm having a first end connected in partially free manner so that it may swivel with respect to said base plate and a second, partially free end connected to a catch hook, said pressure spring being constructed as a plate spring with a bend projecting therefrom to engage and to exert a force on said adjacent surface of said pressure plate, said pressure spring being set in a releasable manner and having a first end constructed as a fork in said ring groove and a second end connected to an opening, said opening engaging said catch hook of said second connecting arm in a releasable manner.

3. The measuring assembly as claimed in claim 2, wherein said pressure plate includes at its top surface a catch receptacle, said catch receptacle engaging with said plate spring by means of its bend and bars disposed on both sides of said plate spring adjoining said catch receptacle.

4. The measuring assembly as claimed in claim 2, wherein said pressure plate includes pressure supports, said pressure supports disposed to rest on said measuring cell, said circuit board disposed with respect to said measuring cell to face said pressure plate, said circuit board including recesses corresponding to said pressure supports, said measuring cell having axially extending channels for engaging said pressure supports in a form-fitting manner, said pressure supports having noses offset thereto.

5. The measuring assembly as claimed in claim 1, wherein there is further included a chamber cover disposed adjacent a surface of said measuring cell remote from said pressure plate to form a gas-tight chamber within said chamber cover, and said chamber having an inlet and an outlet socket, said chamber having a central opening for communicating with said gas inlet opening of said measuring cell.

6. The measuring assembly as claimed in claim 5, wherein there is further included a coupling for connecting a plurality of adjoining, consecutive measuring cells, said coupling interconnecting an outlet socket of one of said plurality of measuring cells to said inlet socket of said adjourning, consecutive measuring cell of said plurality.

7. The measuring assembly as claimed in claim 4, wherein there is included a filter inserted between said measuring cell and said base plate, said filter having receptacles corresponding to said channels of said measuring cell, guide pins corresponding to said guide pins of said chamber cover, a chamber for receiving therein a filter, said chamber having a central opening and being disposed between said central opening and said gas inlet opening of said measuring cell.

8. The measuring assembly as claimed in claim 7, wherein said measuring cell has axially extending channels, and said chamber cover has guide pins extending axially from said surface to engage with said channels of said measuring cell or said receptacles of said filter.