US2962891A

US2962891A - Viscosity responsive device

Info

Publication number: US2962891A
Application number: US752638A
Authority: US
Inventors: Jansson Johannes Gerhard
Original assignee: A Ekstroms Maskinaffar AB
Current assignee: A Ekstroms Maskinaffar AB
Priority date: 1957-08-07
Filing date: 1958-08-01
Publication date: 1960-12-06
Anticipated expiration: 1977-12-06

Description

Dec. 6, 1960 J. G. JANSSON 2,962,891

VISCOSITY RESPONSIVE DEVICE Filed Aug. 1, 1958 I- I I I I I I I ."UII-aI-II menial d6. Qfmasozv United States Patcht O 2,962,891 vrscosn'r RESPONSIVE DEVICE Johannes Gerhard Jansson, Stockholm, Sweden, assignor to Aktiebolaget A. Ekstroms Maskinalfar, Stockholm, Sweden, a Swedish company Filed Aug. 1, 1958, Ser. No. 752,638 Claims priority, application Sweden Aug. 7, 1957 11 Claims. (Cl. 73-55) The invention relates to a method for utilizing the friction losses of a medium flowing through a pipe for adjusting the consistency of the medium and is substantially characterized in that the diflference in pressure relative to the flow between the inlet and outlet end of the pipe is measured and controls a device for adjusting the consistency of the medium.

The invention also relates to a device which according to the method automatically adjusts the consistency of the medium at any moment. Such devices are particularly capable of use in cellulose industries for automatic control of the pulp concentration.

According to the invention a unit comprising two rigid plates and an interjacent diaphragm is secured to form the partition wall between the inlet and outlet of a pipe loop through which the medium is caused to flow, for sensing the difference in pressure occurring at this point and transmitting the same to an outside adjustment device. The casing containing the inlet and outlet can also be designed in such a way that the flowing medium is caused to contact the diaphragm unit from both its sides, the plates being arched at least in the direction of flow in order to obtain an extra pressure component in addition to the dilference in pressure owing to the friction losses. The extra pressure is obtained as a reaction force according to the same physical laws that are valid for the wing of an aeroplane or a blade of a turbine.

The diaphragm plates may be designed and turned in various ways if the plates on both sides of the plane running through the fastening edge of the diaphragm are asymmetrically arched. The plates are, however, preferably arched or bulged in the same direction, the curving of the plates individually being allowed to be of various sizes. The curving of one or both plates may also be asymmetrical in relation to the central axis running through the diaphragm transversally to the direction of flow. It becomes evident that through mounting the diaphragm unit in the partition wall with the convex side being turned to the outlet and inlet ends, respectively, an effect is obtainable which, as desired, either increases or reduces the diiference in pressure.

The purpose of this increase or reduction is to obtain an optimally sensitive, secure, rapid and uniform regulation for a wide range of variations of the consistency of the medium. Supposing the diaphragm placed between the inlet and outlet of the friction loop with the convex side of the plate assembly facing the inlet side, the diaphragm will, as long as the consistency desired is prevailing, remain in a median position balanced by the inlet and outlet pressures as well as the reaction force acting upon the curved surfaces of the plate assembly and if required a biasing force, such as a spring.

If the consistency increases, thereby increasing the pressure difierence between the inlet and the outlet, the diaphragm will move towards the outlet side against the biasing force. At the same time, however, the velocity of the medium decreases and the reaction force acting on the plate assembly will diminish, allowing the dia r 2,962,891 i Patented Dec. 6, 1960 phragm to move still more towards the outlet side increasing the impulse to the external adjustment device.

If, on the other hand, the consistency of the medium decreases the pressure difference will be reduced and thus the diaphragm by the biasing force will move over towards the inlet side. Simultaneously the velocity of the medium increases and also the reaction force on the plate assembly, moving the diaphragm still more towards the inlet.

It is thus seen that the form of the plate assembly generally amplifies the movements of the diaphragm and thus the impulses to the external adjustment device.

In the following description where it is referred to the accompanying drawings, a preferable embodiment is described in detail.

Fig. 1 of the drawings shows a schematic vertical view of the adjustment device according to the invention as a section along the line I I of Fig. 2.

Fig. 2 shows a schematic horizontal view of the device as a section along the line 11-11 of Fig. 1.

Fig. 3 shows in enlarged scale a longitudinal section through the diaphragm unit according to the invention along the line IIII of Fig. l, and

Fig. 4 shows a cross section through the diaphragm unit along the line IV-IV of Fig. 3.

In Fig. 2 is shown a pipe socket 1 intended to be inserted in a pressure pipe of a pulp pump from which socket starts a loop 2 having an inlet 3 and an outlet 4, to the partition wall of which a diaphragm unit 5 is secured which is described more specifically later on. By means of a liquid pump 6 being placed in the inlet 3 of the pipe a portion of the pulp passing through the socket 1 is shunted through the loop 2. Owing to the friction losses of the liquid occurring in loop 2 a lower pressure is efiected at the outlet 4 than at the inlet 3, said difference in pressure being dependent on the viscosity of the liquid and thus adapted to be used for adjusting the same, i.e. in this case the pulp concentration.

The difference in pressure is sensed by the above diaphragm unit 5 arranged in the partition wall, said diaphragm unit comprising a diaphragm 7 (see Figs. 3 and 4) fastened up at its edge and clamped between the two

rigid plates

8 and 9.

In the embodiment shown the plates are arched or bulged in the same direction, in the direction of flow of the liquid as well as in the direction normal to the direction of flow, the convex side of the unit 5 being turned to the inlet 3. Furthermore, the curving of the plates is of difierent size and also individually asymmetrical in relation to the transverse axis of the diaphragm axis 5. The input end of plate 8 is fastened to a shaft 10 which is pivotally arranged on the pipe casing, the outer end of said shaft, for example, by means of a lever 11 for controlling a conventional device for adjusting the pulp concentration.

Owing to the fact that the casing containing the inlet and outlet of the loop is designed in such a way that the liquid when flowing in and out is caused to contact the arched diaphragm unit 5 from both its sides, an extra pressure component is obtained which in the embodiment shown produces an elfect in the opposite direction of the dilference in pressure due to the friction losses occurring in the coil 2, i.e. the diflerence in pressure is reduced. On the lever 11 a spring 12 (Fig. 2) may be arranged to counteract the diaphragm movement, said movement thus, as desired, being modifiable through changing the tension of the spring.

Of course, the invention is not limited to the embodiment shown. The diaphragm unit 5, for example, may be turned in the opposite way, i.e. the convex side directed to the outlet 4, through which measure instead of a reduction an increase of the difference in pressure is effected. For adjusting to a special purpose, it is further possible to modify the curving of the

plates

8 and 9 in VaIIOHS ways.

What I claim is:

l. A device for continuously determining the consistency of a medium flowing in a conduit comprising a loop of pipe extending from said conduit andreturning thereto, comprising a partition wall separating the inlet and outlet of said pipe loop through which the medium flows formed by a diaphragm unit, said diaphragm unit sensing the difference in pressure between said inletand outlet, the central portion of said diaphragm unit being clamped between two rigid plates and secured to a, shaft to operate an adjustment device.

2. A device according, to claim 1', including a casing containing the inlet and outlet designed in such a way that the medium, during its flow, is caused'to contact the diaphragm unit from both its sides, the plates being arched at least in the direction of flow in order to modify the pressure component of the-flowing medium in addition to the difference in pressure caused by the friction losses.

3. A device according to claim 2, in which the plates are arched in the same direction;

4. A device according to claim 3, in which. the radii of curvature of the plates are of. different length.

5. A device according to claim 4, in which the curvature of one plate is asymmetrical} in relation to an axis running through the diaphragm transversely of the direction of flow.

6. A device according to claim 3, in which the convex side ofthe diaphragm and plates unit is turned to the inlet end in order to effect a pressure component reducing the difference in pressure.

7. A device according to claim 3, in which the convex side of the diaphragm and plates unit is turned to the outlet end in order to efiect a pressure component increasing the difference in pressure.

8. A device according to claim 3, in which the plates are also arched in a direction transversally to the direction of flow.

9. A device according to claim 1, in. which the one plate on its one side is fastened to a pivotally arranged shaft carrying a lever acting upon an outside adjustment device.

10. A device according to claim 9, including an adjustable spring acting upon the lever and hindering the movement of the diaphragm.

11. A device to continuously determine the viscosity of a fluid passing through a primary conduit, comprising a branch connection to said conduit, a branch conduit forming a loop having a first end extending from said branch connection and a second end returning thereto, means for forcing a flow of fluid from said primary conduit into said first end of said branch conduit, a flexible diaphragm unit forming a common wall portion of said first and second ends of said branch conduit, at least one plate secured to said diaphragm, a pivot secured to said plate near one end thereof, said pivot extending through the Wall of said conduit, and means mounted exteriorly of said conduit whereby the viscosity of the fluid in the conduit may be determined by the position of said means.

References Cited in the file of this patent UNITED STATES PATENTS