US2315017A - Separator for liquids having different specific gravities - Google Patents

Description

March 36, 1943.. H. A. THOMPSON SEPARATOR FOR LIQUIDS HAVING DIFFERENT SPEIFIC GRAVITIES 3 sheets-sheet 1` Filed Oct. 11, 1938 .Ilhllll. lllrllill-.1r I;

fa f4 /5 March 30, 1943. H. A. THOMPSON 2,315,017

SEPARATOR FOR LQUIDS HAVING DIFFERENT SPECIFIC GRAVITIE'S- Filed 061'.. l1, 1938 3 Sheets-Sheet '2 H. A. THOMPSON March 3o, 1943.

SEFARATOR FOR LIQUIDS HAVING DIFFERENT SPECIFIC GRAVITIES 3 Sheets-Sheet 3 Filed Oct. ll, 1938 Patented Mar. 3G, 1943 sErARATon Foa LIQUms HAVING DIFFERENT srnonlo GRAVITIES Herbert Alexander' Thompson, Benton, England- Appiication october 11, 1938, serial No. 234,452 In Great Britain February 24, 1938 5- eiaims.

This invention relates tol float-actuated means for controlling the discharge of collected separated liquid from a separating device for separating liquids of diierent specio gravities from aV mixture of such liquids which does not tend to form aV true miscible solution.

In the speciiication of my earlier U. S. Patent No, 2,036,730 I have described a separator provided with float controlled means for effecting the automatic discharge of one of the separated liquids when a predetermined amount of the liquid has collected and' the control oat is counterweighted by a movable balance weight which is adjustable in position to provide correct operating conditions when the specic gravities of the separated liquids vary, as in some industrial processes.

The present invention is an improvement in the control device referred to in my abovementioned patent and one object of the present invention is to provide an improved arrangement in which the necessity for the shiitable balance Weight is avoided and a further object isv to provide a simple and satisfactory control device which is self-adjusting for variations in the specic gravities of the liquids passing through the separator and therefore does not require the attention of an attendant.

In the present arrangement, as in the con-4 struction described in the abovementioned U. S. A. patent specication, the discharge of the recovered liquid which collects, as it is separated from the'mixture, in a collecting dome or chamber is controlled by the movements of a lever actuated bya oat moving up and down with the level of the collected liquid (i. e. the line of separation between the collected liquid and the mixture). In theV arrangement according to the present invention a main float and a pilot oat are carried at opposite ends of the lever (or of a lever system) and are arranged so that the pilot float, Which'is always wholly immersed in the iiow' liquid passing through the apparatus, has normallyV a' greater effective action Vthan the main float. Thus, before ,the recovered liquid starts to collect (and both oats are consequently immersed in the same liquid) the actionv of thepilot float overcomes that of the main float but' as the latter becomes immersed in the separatedliquid collected in the dome the change in Weight of the main oat (due to the different specific gravity of the liquid-in which it is now immersed) causes the action ofthe main float to overcome thatY of the pilot Yfloat with the resultth'at the lever on' which' the floats are carried uis ultimately tilted on its fulcrum to cause the opening of a dischargev valve for theJ collected liquid. Both the main floatjand the pilot floats as described hereiny are madel ofthe same size and weight so that they normally have` the same displacement but when the recovered liquid is lighter than the iiow liquid of the'mixture fromrwhich it isjseparated the pilotV oat isl additionally weightedr so that when both floats are immersed in a common liquid (as is the case when no separated liquid has yetv startedv to colf lect) the pilot float acts to raise themainfloat to' the top of the collecting dome but as the lighter liquidV (e. g. oil) collcts'rthe Weight loss of the main float (due to its immersionv in a liquid) becomes less owing to the lighter specific" gravity of the oil andv this change of immersion increasesy the operative Weight of lthe main float and thereby overcomes' thehadditional or biasv weight added to therpilo't float and thefmain float follows the level of oil down and tilts the lever on its fulcrum to cause discharge of the oil when a predetermined amount'has collected.

As the oil is discharged thev heavier liquid of the mixture flows in to take*itsplace'andjuthe pilot floatis again able tolovercome the 'effect of the main float and return thevr leverv to itsA original position.

If the recovered liquid'v is heavier than thev mixture from which it separatesv the apparatus is used in an inverted-'position andthe mainy oat is made heavier than the vpilot'iioat' and the main float decreasesvv in weight as, it becomes immersed in the recoveredv heavier liquid and is able to follow` upA the risingv levell of recovered liquid untildischarge of the collected liquid occurs from the inverted dome or sump,

It willb'e understood that tliepilot lo'atcanpbe made smaller than the main' float providing, that the leverage' distance from the fulcrum to the pilotiioat iscorresponding'ly increased' toy give an equivalent power factor equal to a float of the same sizejas the main float when equal leverages a-jre used. Alternativelya pilot floatjsmaller than the mainoa't'can be employed'with either equal or unequal leverages" forthe two' iloats' if the sZe t0 WeightY rtioof thepilt Hat iS` Suitably ener-.ed in eompa'risenwitn that of" the'main iloat.

The arrangement according" to thepre'ser't invention willV best be understoodfrom theio'llowing' description with reference to the aoconipanying drawings', in which;

Fig. 1 isa diagrammatic representation of a separa-torV with the collecting'doineisl'iow'i Sec'- tion, and showing the positions of the floats before any lighter separated liquid has collected within the collecting dome.

Fig. 2 is a fragmentary view of the top portion of Fig. 1 but showing the positions of the floats just before the collected liquid in the dome commences to discharge.

Figs. 3 and 4 are views corresponding to Figs. 1 and 2 but showing the floats on a lever system instead of on a single lever.

Fig. 5 is a part sectional view of a modified form of separator and,

Figs. 6 and 7 are sectional elevations showing other modications. Y

The separator is shown as suitable for cases in which the recovered liquid (assumed to be a light oil) is of lighter specific gravity than the flowliquid from which it separates. Y

In Figs. 1 to 5 the body of the separator is indicated at I and has a collecting dome 2 in which the lighter separated liquid (i. e. the oil) collects andto which the separated oil is led by upcast pipes 3. The separator has inlet and outlet pipes 4 and 5 and the oil dome 2 has'a water-exchange pipe 6 through which the liquid displaced from the oil dome 2 as the oil collects therein passes back into the body of the separator. These parts I toB correspond with the parts, l, 8, I9 and 26, 9. I0 and 36 respectively of the construction'described in U. S. Specification No. 2,036,730. 'I'he oil which collects in the dome 2 is discharged therefrom, when a predetermined amount has collected, through pipe 1 which is provided with a discharge valve 8 operated by fluid under pressure supplied-to the operating Vcylinder 9. The supply of pressure fluid to the cylinder 9 is controlled by a'rotary or shuttle valve actuated by the movements of the lever I0 in the manner described in Specication 2,036,730 and the lever I Il is float-operated in the manner hereinafter described. The parts I to I0 correspond with the parts 31, V38, 39 and 43 respectively in the construction described in Specification 2,036,730.

In Figs. 1 and 2 of the present case a single lever I0 is shown which is fulcrumed on a shaft I I suitably supported in shaft bearings to reduce friction to the lowest possible degree. At opposite ends of the lever I0 and at equal leverage distances from the fulcrum I I are attached a main iloat'I2 (corresponding to float 42 in the prior patent) and a pilot float I3. The amount of oil which is allowed to collect before discharge occurs is indicated by the distance A and the f lever I0 is pivoted just below the level B (Fig. 2)

pilot iloat I3 is then loaded by weights such as lead shot, iron borings, cement, sand or other suitable loading material, in order to give it a bias over the main float I2 whereby the latter is partially counterpoised so that it tends to rise in the heavier of two liquids of slightly diiferent specific gravities but tends to sink in the lighter of the two liquids, which may be, for instance, fresh water of specic gravity l and oil of .99 specic gravity.

As the two floats were originally constructed to the same weight and volume and their weights were heavier than the same volume of the heaviest 110W liquid to be used, it will be evident that prior to the bias loading of the pilot float neither would have any operative effect over the other when immersed in the heaviest ow liquids, as each is heavier than the liquid and each would actually have a sinkage effort in the same, equal and opposite to each other.

If the apparatus is now filled with fresh water of say 1.0 specific gravity, it will be evident that both floats will each lose the same amount of Weight due to immersion in the same liquid, as any body which is immersed in a liquid loses weight by exactly its volume Weight of the liquid it displaces.

As at first constructed each oat was to be made heavier than the same volume of the heaviest flow-Water it will be evident that on immersion only this excess weight would remain on each as eifective sinking effort and that being so their excess weights would be the same on each side of the fulcrum Il and they would be merely in a state of equipoise.

However, as the pilot float I3 has been given in addition a bias loading over the main float I2, it will be evident under such loading that immersion in say fresh water will result in the main oat I2y becoming buoyant, whilst the pilot float I3 will sink on account of its bias weight, thus overcoming the position of equipoise which would otherwise occur if the oats were of similar weight, as well as equal volumes.

This means that in fresh water the main float will have a denite buoyant effort, which opercharge commences. Suitable stops (not shown) oil level line B and the pilot float I3 is below itA so Y that the latter always remains immersed in the heavier liquid ilowing through the separator and cannot enter the recovered oil space.

The main float I2 Vand the pilot oat I3 are first constructed to exactly the same volumes and weights so that thus far they are the equivalent of each other, and both heavier than the heaviest flow liquid that they may be immersed in.- The ates through the fulcrum shaft Il of the lever I0 to cause the oil-discharge valve 8 to be closed. The floats I2 and I3 and lever I0 thenwhave the position shown in Fig. 1.

If it is now assumed that oil has been recovered from the .flow-water passing through the separator, then this oil will be passed up to the top of the oil dome 2 through pipes 3 and an equivalent volume of water will pass out from the dome 2 through pipe 6 back into the flow through thev separator.

As this oil accumulatesrdownwards in dome 2 it will cover the main float I2 and as this has only been counterpoised to float in water but not in a lighter liquid, the main oat is not buoyant in this oil and must therefore sink, i. e.: follow the oil-water level downwards. in the dome 2.

The pilot oat does not prevent this because asthe oil is lighter than the fresh water it cannot support the same amount of the constructed weight of the float as the fresh water did, and the main float therefore appears to gain in weight relative to the pilot float, whereas the pilot float still remains immersed in fresh water and its apparent loss in weight due to immersion is unchanged. On this account the arrangement results in the bias being changed over to the main float without any shiftof balance weights, as due to oil immersion its excess weight is now heavier than that exerted by the pilot float which is still in the fresh water.

This means that the main float I2 has now a definite sinking effort in 4the oil and so gradually falls as the oil accumulates and when the floats and lever reach the position shown in Fig. 2 in which the lever I becomes horizontal the shuttle-valve will be reversed, causing the oil discharge valve 8 to be opened to allow the accumulated oil to be discharged automatically from the oil dome 2.

As the oil is discharged the main float I2 again becomes buoyant in the heavier liquid and will follow the oil-water level upwards, because the equivalent amount of flow-water will re-enter the dome by pipe 6, and when the main oat reaches its top position again, the oil discharge valve will be automatically closed and the accumulation of oil will commence afresh.

Now supposing the oil-contaminated water flowing through the separator changes to a water of heavier specific gravity, say salt water, and both oats as balanced for fresh water, are immersed therein, it will be found that the main float is still buoyant in the same manner as in the fresh water because both floats having the same volumes will each lose their volumeweight of salt water, but the pilot float will still have its bias loading in addition.

This means that in any flow-liquids the two oats gain or lose equal volume-weights in every case, so that any apparent changes in weight due to immersion in changed flow liquids are automatically cancelled or balanced out as between the two fioats and the counterpoise bias given by the pilot float due to its additional loading is maintained.

When the oil separated from the salt water accumulates in the oil dome 2 the main float gains an increase in weight as before and thereby increases its excess weight. As the pilot oat still remains in the salt water its excess weight cannot increase and therefore (as in the case of the fresh water flow), the bias is transferred to the main oat without any shift of balance weight and the main float will be heavier than the pilot oat and so sink with the oil-water level and ultimately cause the oil discharge valve S to be opened to discharge the oil.

In Figs. 3 and 4 there is shown an arrangement similar to that shown in Figs. 1 and 2 except that the lever carrying the floats I2 and I3 is in two parts Iii and i fulcrumed at II and II and connected by a link III. This arrangement operates in the same way as that described with reference to Figs. 1 and 2 and enables longer leverages to be obtained without the necessity of having the oil dome 2 made larger. In Fig. 3 the parts are shown in the positions taken up prior to the accumulation of oil in the dome 2 while Fig. 4 shows their positions just prior to discharge of the collected oil. It is obvious that other forms of multiple levers can be employed. Y Fig. 5 shows an arrangement similar to the construction shown in Figs. 3 and 4 except that the oil dome 2 is partially housed Within the body I of the separator in order to reduce the total height of the complete apparatus. In this figure the final positions of the oats I2 and I3 just prior to discharge of the recovered oil is shown in dotted outlines.

Fig. 6 shows a construction in which a single lever it is used to carry the floats I2 and I3 as in Figs. 1 and 2 but in this case the oil dome 2 and the oil upcast channel 3 are incorporated in the body of the separator. Thelever Ill', pivoted at II, is housed partly in the oil dome 2' and partly in the rest of the separator to give increased leverage while economising in the size and construction of the complete apparatus. This figure also shows the shuttle valve I5 which is actuated by the lever IIJ and controls the supply and discharge of pressure fluid to and from the cylinder 9 through pipes indicated at I6.

Fig. 'I shows a similar arrangement to Fig.v 6.

but in this case the oil collecting chamber 2 occupies the whole top part of the separator and the pilot float I3 also carries an extension II forming a valve controlling the outlet of flow water from the separator. Instead of being attached directly to the ends of the lever I0 the floats are carried on extensions I8 and I9 pivoted to the ends of the lever so that the floats can travel in vertical instead of radial paths. Reference 20 indicates an air or gas vent pipe leading to the atmosphere. Y

In all the constructions illustrated in Figs. 4 to '7 the operation is the same as that described with reference to Figs. 1 and 2.

The above described self-balancing automatic gear enables all forms of hand control or setting of the specific gravity gear to be dispensed with in the employment of the apparatus, as the twin floats enable the plant to deal with fresh or salt water at any temperature as main flow through the separator, and at the same time discharge oil of any kind that has a lighter specific gravity than the ow-water. On this account the plant is especially suitable for dealing with oily-condensate water from steam-engines or heating coils, as the apparatus is self-correcting for specific gravity changes occurring in the condensate either from cold to hot or vice-versa.

The apparatus may be however employed for any purpose wherever two or more non-mixable liquids have to be separated and discharged, particularly where the flow-liquid is liable to change in specific-gravity or have its specific gravity altered due to heating or cooling, as it is selfcorrecting where changes occur in the specific gravities of the liquids.

The same apparatus in an inverted form can be utilised for discharging oils that are heavier than the now-water, by employing it in conjunction with the inverted separator shown in Fig. '7 of Specification No. 2,036,730, but in this inverted position of course the main float is made heavier than the pilot float and has an apparent loss in weight as it becomes immersed in the heavier oil instead of in the flow water, so that in such cases it is an upward otational effort which is transferred from the pilot float to the main oat. Apart from this the operation is the same as that described for oils lighter than the flow liquid from which they are separated.

What I claim as my invention and desire to secure by Letters Patent is:

1. Apparatus for the separation of liquids of different specific gravities from a mixture of such liquids comprising a closed receptacle, in which the mixture separates into a lighter upper liquid and a lower heavier liquid, said receptacle having an inlet for the mixture of liquids, a lower outlet for the heavier liquid, an upper outlet for the lighter liquid, means including a valve controlling the flow of the lighter liquid through said upper outlet, power means operated by fluid under pressure for actuating said valve, means to supply a fluid under pressure to said power means, a

'that the pilot oat rises above its normal level when the main oat is immersed in the lighter liquid, thereby actuating said second valve to admit a fluid under pressure to said power means to open said upper outlet valve.

2. In an apparatus as claimed in claim 1, a chamber in open communication with said receptacle in which the lighter liquid collects and in which said floats and connected lever are located, said chamber having therein a predetermined plane of maximum separation between the lighter and heavier liquids, said fulcrum of said lever being located below said plane of maximum separation.

3. An apparatus as claimed in claim 1, further characterized by said fulcrum of said lever located below the plane of selected maximum separation of the lighter and heavier liquids, said main float lying above the lever, said pilot float lyingbelow the lever.

4. An apparatus as claimed in claim 1, further characterized by the fact that the pilot and main oats are connected to the lever at different horizontal levels with the main oat uppermost and adapted to float in the mixture of liquids and sink in the lighter separated liquid, and means to prevent the pilot iioat from rising above the selected line of separation between the liquids.

5. An apparatus as claimed in claim 1, further characterized by the fact that said pilot oat is weight biased with respect to the main oat to normally sink in the liquid mixture with an accompanying rise of the main iioat in the mixture, said main float constructed and arranged as to Weight to sink in the lighter separated liquid.

HERBERT ALEXANDER THOMPSON.

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