GB1559517A - Device for separating liquids of different densities - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO A DEVICE FOR SEPARATING LIQUIDS OF DIFFERENT DENSITIES (71) We, RELLUMIT INTER, a French Body Corporate of 11, Avenue Dubonnet, "Le Doublon", Courbevoie, 92, France, formerly of 123 Avenue du General de Gaulle, 92 250 La Garenne-Colombes, France, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it it to be performed, to be particularly described in and by the following statement :- This invention relates to a device for separating two liquids having different densities, for example a hydrocarbon and water.

Liquid separators are known, for example oil separator or water removers, which comprise a container through which a first liquid to be purified flows and in which a second liquid is separated off from the first liquid owing to a difference in the densities of the two liquids. In this container, there is usually disposed a float which follows the level of the second liquid above which there is a certain amount of the first liquid which is constantly renewed. In order to be able to drain the pollutant liquid from the container, the separator is provided with a discharge device comprising a valve whose needle valve member is mechanically coupled with the float so as to open when the latter reaches a predetermined drainage level.

These known separators have a major drawback which resides in the poor reliability of their operation. Indeed, the mechanical energy that the float is capable of transmitting to the valve in order to open it is relatively low and, above all in the event of a jamming of the needle valve or owing to an appreciable pressure of the liquid to be purified, the float does not always manage to raise the needle valve member from its seat to produce the drainage.

A device according to the present invention for separating two liquids having different densities comprises: a container; a float ; a discharge orifice in the lower part of the container for discharging the liquid having the higher density; a closure device which is normally closed but is opened from time to time for the discharge of the higher density liquid ; inlet and outlet orifices at the upper part of the container, the outlet orifices being for the discharge of the lowerdensity liquid; a magnetically controlled switch in the wall of the container at a height corresponding to the desired maximum level of the liquid of higher density in the container, the switch being connected in a circuit in series with a source of current, the float being provided with a magnetic element co-operating with the said magnetically controlled switch.

The said circuit may comprise a sound or light signalling device, such as an indicator lamp. The drainage of the higherdensity liquid can then be achieved manually when the signalling device is actuated. In the preferred form of the separator, the closure device is electromagnetically controlled and its control coil is connected in the said circuit. In this case, the drainage of the higher-density liquid is entirely automatic and is achieved as soon as the float reaches the desired maximum level. Advantageously, the circuit is provided with an electro magnet relay whose coil is connected in series with said switch and which comprises a working contact inserted in the control coil of the closure device.

The invention will be better understood from the ensuing description of an example of a separating device embodying the invention.

In the accompanying drawings: Fig. I shows an axial sectional view of a separator of two liquids having different densities, embodying the invention ; Fig. 2 is an axial sectional view taken on line 2-2 of Fig. I ; Fig. 3 is a radial sectional view taken on ] ine 3-3 of Fig. 2, and Fig. 4 is a diagram of the separator of Figs. 1 to 3 and its associated electrical control means.

In the embodiment shown in the Figures, the separator comprises a container or vessel I of suitable shape closed by a cover 2 which is provided with input and output orifices 3 through which the liquid to be purified passes. By way of example, it may contain a hydrocarbon from which water must be removed.

Upwardly extending from the bottom 4 of the container 1 are two spaced-apart vertical guide rods 5 which guide a float 6 which is capable of moving vertically in the container 1. In the known manner, this float follows the level of the pollutant liquid to be discharged which has the highest density, the main liquid remaining on the pollutant liquid owing to the difference of densities.

The container 1 communicates with a receiving chamber 7 by way of an orifice 8 which extends through the bottom 4. This chamber communicates with a discharge orifice 9. A seat 10 is formed around the orifice 8 in the chamber 7 and cooperates with a closure element 11 in the form of a membrane which is biased to its closing position by a plunger core 12 constituting a valve member owing to the action of a coil spring 13. The core 12 is surrounded by a control coil 14.

The assembly of the discharging or draining device just described is protected by a cover 15 which is fixed to the container by elastically yieldable prongs 16.

A cavity 17 is formed in the outer wall of the container 1. This cavity is closed by a cover 18 and contains an insulating mount ing plate 19 carrying a first switch 20 which is controlled magnetically and disposed ver tically in the cavity 17 and biased to the closing position by a small permanent magnet 21 mounted in facing relation to this switch in the cover 18.

A second switch 22 also controlled magnetically is disposed horizontally above the first switch. The second switch 22 is of the normally-open-type. The float 6 has, in front of the cavity 17, a permanent magnet 23 which is capable of producing, when it passes in front of the respective switches, on one hand, the closure of the switch 22 by direct action on the latter, and, on the other hand, the opening of the switch 20 by cancelling out the action of the permanent magnet 21 which therefore has a lower force of attraction, In Fig. 4 it can be seen that the switches 20 and 22 are inserted in series in the excitation circuit of a coil 24 of a relay 25, the assembly being connected to a source of voltage 26, the coil 24 being connected in parallel with a diode 27 for suppressing transients.

The relay 25 comprises a contact 28 which is self excited and a control contact 29 which is inserted in the circuit of the coil 14 of the draining device. The latter is also mounted in parallel with a diode 30 for suppressing transients. It will be understood that the coil 14 and the control contact 29 are connected to the terminals of the source of voltage 26.

A signal or indicator lamp 31 is inserted in series in the circuit of the coil 14.

The device operates in the following manner: When the device has just been drained, the float 6 is located on the bottom 4 of the container. Under these conditions the magnet 23 maintains the switch 20 open in opposition to the action of the magnet 21. As the level of the pollutant liquid of higher density rises in the container, the float also rises. At a given moment, the action of the magnet 21 on the switch 20 overrides that of the magnet 23 so that the switch closes.

When the float 6 reaches the authorized maximum level, its magnet 23 closes the switch 22 and this excites the relay 25. As the latter is self-supplied by the contact 28, it closes the circuit of the coil 14 through the contact 29 and thus opens the draining device in opposition to the action of the spring 13.

In being discharged from the container, the pollutant liquid causes the float 6 to descend and, in a first stage, opens the switch 22. Thereafter, in reaching its lower position, the float opens the switch 20 and this cuts off the supply of current to the relay 25 and consequently to the coil 14.

The orifice 8 once again closes and the pollutant liquid can then accumulate in the container 1.

Note than in its simplest form and in the case of a manual drainage of the container 1, solely the switch 22 may be employed in series with the indicator lamp 31 or some other sound or light signalling device which, when it is actuated, incites the operator to drain the container manually.

Claims (6)

1. WHAT WE CLAIM IS :- 1. A device for separating two liquids having different densities comprising: a container ; a float; a discharge orifice in the lower part of the container for discharging the liquid having the higher density; a clo- sure device which is normally closed but is open from time to time for the discharge of the higher density liquid; inlet and outlet orifices at the upper part of the container, the outlet orifices being for the discharge of the lower-density liquid; a magnetically controlled switch in the wall of the con tainer at a height corresponding to the de sired maximum level of the liquid of higher density in the container, the switch being connected in a circuit in series with a source of current; the float being provided with a magnetic element co-operating with une saia magnetically controlled switch.
2. 2. A device as claimed in claim 1, wherein the circuit comprises a sound or light signalling device.
3. 3. A device as claimed in claim 1 or 2, wherein the closure device is electromag netically controlled and has a control coil connected in the said circuit.
4. 4. A device as claimed in claim 3, wherein the circuit is provided with an electromagnetic relay which comprises a coil connected in series with the said switch, the relay having a contact connected in the circuit of the control coil of the said closure device.
5. 5. A device as claimed in claim 4, wherein the said electromagnetic relay comprises a holding contact; and a second mag netically controlled switch is connected in the circuit of the said control coil, the second switch being located below the firstmentioned magnetically controlled switch determining the maximum level of the mgner aensity iiquia, ine secona swmcn being a normally closed switch and being opened by the magnetic element on the float when the latter reaches a predetermined lower level in the container.
6. 6. A device as claimed in claim 5, where in the said second switch is maintained nor mally closed by a magnetic element exerting a force less than that of the magnetic ele- ment of the float.

   7 A device for separating two liquids having different densities, substantially as herein described with reference to and as shown in the accompanying drawings.