DE2809264A1 - Pressure pick=up using tubular ring - separated from diaphragm by elastic plastics, and with electrical connections to recorder - Google Patents

Abstract

The pickup has a tubular ring whose end rests on the tested object. It holds inside means for transmission of the measured pressure through a transmission element to a mechanical-electrical transducer connected to a recording instrument. A diaphragm (9) is mounted inside the ring (6), at a distance from its end (7). Space (11) between the diaphragm (9) and the ring (6) inside surface (8) is filled with a flexible plastic (12), so that the ring end (7) is continued by the plastic (12).

Description

Pressure consumer

The invention relates to a pressure transducer with a tubular ring, one end face of which is designed to rest on the measurement object and in the inside of which is provided with means for transmitting the pressure to be measured over a transmission link to a mechanical-electrical converter on the connecting lines for a recorder are connected.

Pressure sensors of this type are used in non-invasive measurements of e.g. intraocular, intrauterine or intracranial pressures are used. The pipe-like one Ring prevents the surface tension of the measurement object from falsifying the measurement. Only when the entire face of the pressure transducer with the tubular ring is on is applied to the object to be measured, a pressure measurement is carried out.

It is therefore of great importance that there are present inside the ring Pressure transmission means in one plane with the corresponding face of the ring away- conclude. The pressure transmission means should in order to achieve good measurement results to be kept stiff in relation to the ring The type mentioned at the beginning is in the journal "J. Obstet. Gynaec. Brit. Emp." 64, 1957, pages 59 to 66 described. The pressure transmission medium here is a piston, which is movable inside the ring and along its longitudinal axis. At a It is extremely difficult for such a pressure sensor to remove the application-side end face to keep the tubular ring and the piston in one plane. Furthermore, it can There are friction losses due to particles trapped between the piston and the Penetration of the ring and which can lead to incorrect measurement results.

The invention is based on the object of providing a pressure transducer To create the type mentioned at the beginning, in the case of malfunctions as a result of soiling can be avoided and in which a falsification of the measurement result by an undesired Displacement between the pressure transmission means and the ring is prevented.

The object is achieved according to the invention in that a membrane is present, which is on the inner wall of the ring at a distance from the flat face is attached, and that the space between the membrane and the inner wall of the ring is filled with elastic plastic, so that the flat face is steplessly through the plastic is continued. Because of this training the pressure transducer can no dirt particles between the pressure transmission medium and the inside of the Penetrate the ring. Furthermore, it is easy to remove the space between the membrane and the Inner wall of the Fill the ring with elastic plastic so that the flat face is continued steplessly.

Further details of the invention emerge from the subclaims. The invention is described below using an exemplary embodiment shown in the drawing explained in more detail.

The figure shows a section through a pressure sensor 1 according to Invention. In the embodiment, the intracranial pressure is measured by the pressure transducer is applied to the open fontanel 2 of a small child. The pressure sensor 1 is shown schematically on a connecting lines 3, 4 Recording device 5 connected.

The pressure sensor has a tubular ring 6, one of which End face 7 to rest on the measurement object, in the example of the fontanel 2, flat is trained.

On the inner wall 8 of the ring 6 and at a distance from its flat end face 7, a membrane 9 is attached to which a transmission member 10 is attached. The space 11 present between the membrane 9 and the inner wall 8 of the ring 6 is filled with elastic plastic 12, e.g. silicone rubber, so that the plane End face 7 is continued by the plastic 12. The membrane 9 has on the Inner wall 8 of the ring 6 has a bead raised toward the end face 7 of the ring 6 16 to hold the elastic plastic 12 on.

The bead 16 can also be provided directly on the inner wall 8.

In the interior of the ring 6 between that attached to the membrane 9 Transmission member 10 and a holder 13, a piezoelectric element 14 is attached. arranges, on which the connecting lines 3 and 4 are attached, which are arranged in the holder 13 via Channels 15, 16 are led to the recorder 5.

When pressure from the fontanel 2 on the elastic plastic 12 is exercised, it is transmitted to the membrane 9 and the transmission member 10. The plastic 12 and the membrane 9 bend slightly inward. The bend will transferred to the piezoelectric element 14 by means of the transmission member 10, so that an electrical voltage corresponding to the pressure is generated. This will via the connecting lines 3, 4 to the registration device 5 for registering the pressure fed.

Due to the fact that there is no gap between the elastic plastic 12 and the tubular ring 6 is present, no dirt particles can be here that would affect the measurement accuracy. It is beneficial to have a Use cold-vulcanized plastic, as this is poured directly into space 11 can be. The stepless transition between the flat face 7 and the plastic 12 can be controlled by optical means based on the light reflection of the plastic will.

Claims (5)

Claims pressure sensor with a tubular ring, one of which The face to rest on the measurement object is flat and in its interior Means are provided for transmitting the pressure to be measured via a transmission element to a mechanical-electrical converter on the connecting lines for a recording device are connected, that is, a membrane (9) is present on the inner wall (8) of the ring (6) at a distance from the flat End face (7) is attached, and that the space (11) between the membrane (9) and the inner wall (8) of the ring (6) is filled with elastic plastic (12), so that the flat end face (7) is continuously continued through the plastic (12). 2. Pressure sensor according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the inner wall (8) of the ring (6) or the membrane (9) to one for Front side (7) of the ring (6) raised bead (16) to hold the elastic Has plastic (12). 3. Pressure sensor according to claim 1 or 2, d a d u r ch g e k e n n notices that the elastic plastic (12) is silicone rubber. 4. Pressure sensor according to one of claims 1 to 3, d a d u r c h g e k e n n n z e i c h n e t 5 that the transmission member (10) is attached to the membrane (9) is. 5. Pressure sensor according to one of claims 1 to 3, d a d u r c h g e k e n n z e 1 c h n e t that the membrane (9) itself is the transmission element.