US3302638A

US3302638A - Mercury sphygmomanometers

Info

Publication number: US3302638A
Application number: US310438A
Authority: US
Inventors: Parera Pedro Pere; Llaurado David Fabra
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-09-24
Filing date: 1963-09-20
Publication date: 1967-02-07
Anticipated expiration: 1984-02-07
Also published as: FR1370978A; BE637780A; NL298241A; CH398872A; DK106359C; GB1054326A

Description

Feb- 7, 1967 P. P. PARERA ETAL 3,302,638

MERCURY SPHYGMOMANOMETERS Filed Sept. 20, 1963 24 -sEM/-F/L rf@ 1 23 ,cm/P85555 AIR United States Patent Office 3,32,638 Patented Feb. 7, 1967 4 Claims. (cl. 12s- 2.05)

The present invention refers to improvements in or relating to mercury sphygmomanometers, and more particularly to an apparatus for measuring arterial tension.

An important object of the present invention is to provide a sphygmomanometer of such dimensions as to be readily carried on the physicians person vand which in use assures an easy and accurate reading.

To accomplish the above and other -objects and advantages, the invention comprises a housing constituting a compression chamber having in its base a mercury supply, a measuring tube located within the housing and tapering upwardly from its lower end which is in communication with the mercury supply, With the upper end of the tube being provided with a semi-filter through which the tube communicates with the interior of the compression chamber, an inlet for the housing in communication with the mercury supply and with a compressor armlet via a suitable connection such las a hose, a semi-filter located within the inlet, ia further inlet in the housing communicating with the interior of the tube at a position slightly above the zero level of the mercury column and a semi-filter positioned in the latter inlet with such latter inlet serving to equalize the atmospheric pressure with that of the interior of the tube and the compression chamber for obtaining absolute precision in the measurement `of the arterial tension.

Further objects and advantages of Ithe invention will become more readily apparent from the ensuing detailed description and annexed drawings, and in which drawings:

FIGURE 1 is a vertical sectional view of an apparatus embodying the present invention, and

FIGURE 2 is an elevational view on a reduced scale of the apparatus shown in FIGURE 1.

FIGURES 1 and 2 show a manometer upwardly tapered tube 15 which d-ue to its form regularizes the manometric scale, reducing it and making it proportional. The lower part of the tube 15 is introduced in a syphon fashion within la mercury receptacle 16.

The upper part of the tube 15 carries a semi-filter 17 which functions as a stopper for the tube. A housing 18 surrounds the tube and forms the compression chamber which embraces the full length of the tube. Hence, the chamber is of the same length as the tube or centimeters, thus reducing the size of the apparatus to a minimum.

A cylindrical lens or prism 19 having Ia scale thereon is placed at the front or inside the compression chamber -to facilitate the reading of the mercury column.

The base of the housing serves as a mercury receptacle 20 which is `completely filled without a single air bubble and which only communicates with 4the exterior through an inlet 21 in which a semilter 22 is placed to avoid spilling of the mercury exteriorly of the apparatus.

A fitting 23 is provided for the inlet 21 and the tting is in communication with a compressor armlet (not shown) by way of a flexible conduit such asa tube associated with the fitting.

Upon injecting compressed yair through the fitting 23 related to the inlet 21, the mercury rises in the tapered tube 15 indicating the pressure and forces the air situated -above the mercury column through the semiiilter 17 towards the compression chamber 18 in which the air possesses similar characteristics to those of ambient conditions due to the fact that prior to using the apparatus, the interior of the chamber was placed in communication with the ambient atmosphere through a semifilter 24 the mouthpiece of which is obstructed by the mercury when the latter rises in the manometric tube 15.

The dimensions of the casing holding the various components of the apparatus are approximately x 112 X 3() mm.

It will be appreciated that by virtue of the upwardly tapering manometer tube 15 the capacity thereof will assure a perfect reading since, by diminishing the section of the tube in the upward direction, the column of mercury will likewise be reduced in volume :and in Weight. Since the height attained in a manometer tube when closed is a function of its diameter and thus in direct relation to its section, provided the temperature and volume of the compression chamber 18 remains constant, the tube and chamber function in the form of a balance, so to speak, with the pressure required to be measured being exerted at the entrance to the tube and the opposing compression from the compression chamber being exerted on the other end of the tube and to which lat- -ter pressure is added the weight of the rising column of mercury. Hence, if one of the values is maintained constant the height obtained by the mercury column at the same exterior pressure will 'be in inverse relation to the section of the mercury column. The graduation of the column will be closer the higher the point of measurement or, when approaching 300 mm. of mercury, there can `be obtained a completely regularly marked scale.

By reason of the inlet and semi-filter 24 it is possible to equalize the internal and ambient pressures and such inlet is closed upon the rising of the mercury column.

The invention is not to be confined to any strict conformity to the showings in the drawings but changes or modifications may be made therein so long as such changes or modifications mark no material departure from the spirit and scope of the appended claims.

What we claim is:

1. An ,apparatus for measuring `arterial tension comprising a housing constituting a compression cham-ber and having upper and lower ends, a mercury supply in the lower end of the housing, an upwardly tapering tube having upper and Ilower ends within the compression chamber communicating at its lower end with the mercury supply and at its upper end to the compression chamber, and a semi-filter yclosure means communicating exteriorly of the housing and with the interior of the tube in proximity to the zero level of the mercury column in the tube.

2. The apparatus for measuring arterial tension as References Cited by the Examiner in claim 1 in which said housing and tube are UNITED STATES PATENTS 3. The apparatus for measuring arterial tension as 1671785 9/1875 Pond 128`2-05 claimed in claim 1 including a semilter c-losure means 5 1,245,559 11/1917 Booth 12S-'205 X for the upper end of the tube constituting a fluid im- 21669125 2/1954 Hesse 73-402 pervious connection between the compression chamber FOREIGN PATENTS and the interior `of the tube.

4. The apparatus for measuring larterial tension as claimed in claim 3 including an inlet communicating With 10 RICHARD A G AUDET prima Examiner the mercury supply and With a compression armlet, rery spectively, and a semi-filter located in said inlet. SIMON BRODEKEXHMIIQI'.

1,192,165 4/1959 France.

Claims

1. AN APPARATUS FOR MEASURING ARTERIAL TENSION COMPRISING A HOUSING CONSTITUTING A COMPRESSION CHAMBER AND HAVING UPPER AND LOWER ENDS, A MERCURY SUPPLY IN THE LOWER END OF THE HOUSING, AN UPWARDLY TAPERING TUBE HAVING UPPER AND LOWER ENDS WITHIN THE COMPRESSION CHAMBER COMMUNICATING AT ITS LOWER END WITH THE MERCURY SUPPLY AND AT ITS UPPER END TO THE COMPRESSION CHAMBER, AND A SEMI-FILTER CLOSURE MEANS COMMUNICATING EXTERIORLY OF THE