GB1572669A

GB1572669A - Manufacture of esters

Info

Publication number: GB1572669A
Application number: GB22276/77A
Authority: GB
Original assignee: Imperial Chemical Industries Ltd
Current assignee: Imperial Chemical Industries Ltd
Priority date: 1977-05-26
Filing date: 1977-05-26
Publication date: 1980-08-28
Also published as: JPS53147040A; ZA782481B; NL7805736A; AU3584578A; DE2822472A1; FR2391995A2

Description

(40 parts) is removed bv distillation at 200"C/1.0 mm Hg pressure.

The product, m-phenoxybenzyl 2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (360 parts) has a cis :trans isomer ratio of 37:63.

Example 3 Tetraisopropyl titanate (2.7 parts) is added to a mixture of methanol (38 parts), 3-phenoxybenzylalcohol (202 parts) and ethyl 2 ,2-dimethyl-3-(2 2-dichlorovinyl) cyclopropane-1-carboxylate (cis:trans isomer ratio 40:60) (270 parts) stirred under a nitrogen atmosphere at normal room temperature.

The colourless clear mixture is heated to 135-140"C over 1 hour and maintained at this temperature until the 3-phenoxybenzyl alcohol content of the mixture is less than 2.0%. During the reaction mixture is maintained at constant volume by the addition of dry toluene, simultaneously allowing the toluene/ethanol mixture to distil from the reaction mixture.

Upon completion of the reaction the residual ethyl 2,2-dimethyl-3-(2,2dichlorovinyl)cyclopropane-1-carboxylate (30 parts) is removed by distillation at 200"C/1.0 mm Hg pressure.

The product, m-phenoxybenzyl 2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (382 parts) has a cistrans isomer ratio of 39:61.

Example 4 Tetraisopropyl titanate (7.2 parts) is added to dry methanol (50 parts) stirred under a nitrogen atmosphere at normal room temperature. To the mixture. a cloudy white suspension, is added ethyl 2,2 dimethyl-3-(2 2-dichlorovinyl) cyclopropane-l-carboxylate (cis:trans isomer rato 40:60) (118.5 parts) and 3-phenoxybenzyl alcohol (95 parts).

The mixture is heated to 158-160"C over 1 hour and maintained at this temperature until the 3-phenoxybenzyl alcohol content of the mixture is less than 2%. During the reaction the mixture is maintained at constant volume by the addition of dry xylene, simultaneously allowing the xylene/ethanol mixture to distil from the reaction.

Upon completion of the reaction the residual ethyl 2,2-dimethyl-3-(2,2- dichlorovinyl)cyclopropane-1-carboxylate (30 parts) is removed bv distillation at 200"C/1.0 mm Hg pressure.

The product. m-phenoxybenzyl 2.2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (118 parts) has a cis trans isomer ratio of 42:58.

Example 5 The procedure described in Example I is repeated except that the 263.5 parts of ethyl 2,2-dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate are replaced by 245 parts of methyl 2,2-dimethyl-3-(2,2dichlorovinyl) cyclopropane-1-carboxylate (cis:trans isomer ratio 45:55). There are obtained 350 arts of m-phenoxybenzyl 2,2-dimethyl-3-2,2-dichlorovinyl) cyclopropane-1-carboxylate having a cis:trans isomer ratio of 40:60.

WHAT WE CLAIM IS: 1. A process for the preparation of esters of m-phenoxybenzyl alcohol and its a-cyano and a-ethinyl derivatives with carboxylic acids which comprises mixing a methyl or ethyl ester of the carboxylic acid, m-phénoxybenzyl alcohol or its a-cyano or a-ethinyl derivative and a freshly-prepared methanolic suspension of tetramethyl titanate obtained by addition of tetraisopropyl titanate to dry methanol, and then heating the reaction mixture so that the methanol or ethanol which is formed in the reaction distils from the reaction mixture, until reaction is substantially complete.

2. A process as claimed in claim 1 wherein the reaction temperature is between 80" and 16û C.

3. A process as claimed in claim 1 or claim 2 wherein the reaction is carried out in the presence of an inert solvent.

4. A process as claimed in claim 3 wherein the inert solvent is such that the reaction mixture boils at the desired reaction temperature so that the methanol or ethanol formed during the process is distilled off with a part of the solvent.

5. A process as claimed in claim 4 wherein the inert solvent is added to the reaction mixture at a rate such that it balances the rate of distillation of solventl methanol or solvent/ethanol from the reaction mixture.

6. A process as claimed in any one of claims 1 to 5 wherein the amount of tetramethyl titanate catalyst used is from 0.0005 to 0.05 mol per mol of phenoxybenzylalcohol.

7. A process as claimed in any one of claims 1 to 6 wherein the methyl or ethyl ester of the carboxylic acid is used in excess over the m-phenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative.

8. A process as claimed in claim 7 wherein from 1.05 to 1.20 moles of methyl or ethyl ester of the carboxylic acid are used per mol of m-phenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative.

9. A process as claimed in any one of claims 1 to 8 wherein the carboxylic acid is a 2,2-dimethylcyclopropane carboxylic acid which gives insecticidal esters with mphenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative.

10. A process as claimed in claim 9

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (40 parts) is removed bv distillation at 200"C/1.0 mm Hg pressure. The product, m-phenoxybenzyl 2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (360 parts) has a cis :trans isomer ratio of 37:63. Example 3 Tetraisopropyl titanate (2.7 parts) is added to a mixture of methanol (38 parts), 3-phenoxybenzylalcohol (202 parts) and ethyl 2 ,2-dimethyl-3-(2 2-dichlorovinyl) cyclopropane-1-carboxylate (cis:trans isomer ratio 40:60) (270 parts) stirred under a nitrogen atmosphere at normal room temperature. The colourless clear mixture is heated to 135-140"C over 1 hour and maintained at this temperature until the 3-phenoxybenzyl alcohol content of the mixture is less than 2.0%. During the reaction mixture is maintained at constant volume by the addition of dry toluene, simultaneously allowing the toluene/ethanol mixture to distil from the reaction mixture. Upon completion of the reaction the residual ethyl 2,2-dimethyl-3-(2,2dichlorovinyl)cyclopropane-1-carboxylate (30 parts) is removed by distillation at 200"C/1.0 mm Hg pressure. The product, m-phenoxybenzyl 2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (382 parts) has a cistrans isomer ratio of 39:61. Example 4 Tetraisopropyl titanate (7.2 parts) is added to dry methanol (50 parts) stirred under a nitrogen atmosphere at normal room temperature. To the mixture. a cloudy white suspension, is added ethyl 2,2 dimethyl-3-(2 2-dichlorovinyl) cyclopropane-l-carboxylate (cis:trans isomer rato 40:60) (118.5 parts) and 3-phenoxybenzyl alcohol (95 parts). The mixture is heated to 158-160"C over 1 hour and maintained at this temperature until the 3-phenoxybenzyl alcohol content of the mixture is less than 2%. During the reaction the mixture is maintained at constant volume by the addition of dry xylene, simultaneously allowing the xylene/ethanol mixture to distil from the reaction. Upon completion of the reaction the residual ethyl 2,2-dimethyl-3-(2,2- dichlorovinyl)cyclopropane-1-carboxylate (30 parts) is removed bv distillation at 200"C/1.0 mm Hg pressure. The product. m-phenoxybenzyl 2.2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate (118 parts) has a cis trans isomer ratio of 42:58. Example 5 The procedure described in Example I is repeated except that the 263.5 parts of ethyl 2,2-dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate are replaced by 245 parts of methyl 2,2-dimethyl-3-(2,2dichlorovinyl) cyclopropane-1-carboxylate (cis:trans isomer ratio 45:55). There are obtained 350 arts of m-phenoxybenzyl 2,2-dimethyl-3-2,2-dichlorovinyl) cyclopropane-1-carboxylate having a cis:trans isomer ratio of 40:60. WHAT WE CLAIM IS: 1. A process for the preparation of esters of m-phenoxybenzyl alcohol and its a-cyano and a-ethinyl derivatives with carboxylic acids which comprises mixing a methyl or ethyl ester of the carboxylic acid, m-phénoxybenzyl alcohol or its a-cyano or a-ethinyl derivative and a freshly-prepared methanolic suspension of tetramethyl titanate obtained by addition of tetraisopropyl titanate to dry methanol, and then heating the reaction mixture so that the methanol or ethanol which is formed in the reaction distils from the reaction mixture, until reaction is substantially complete. 2. A process as claimed in claim 1 wherein the reaction temperature is between 80" and 16û C. 3. A process as claimed in claim 1 or claim 2 wherein the reaction is carried out in the presence of an inert solvent. 4. A process as claimed in claim 3 wherein the inert solvent is such that the reaction mixture boils at the desired reaction temperature so that the methanol or ethanol formed during the process is distilled off with a part of the solvent. 5. A process as claimed in claim 4 wherein the inert solvent is added to the reaction mixture at a rate such that it balances the rate of distillation of solventl methanol or solvent/ethanol from the reaction mixture. 6. A process as claimed in any one of claims 1 to 5 wherein the amount of tetramethyl titanate catalyst used is from 0.0005 to 0.05 mol per mol of phenoxybenzylalcohol. 7. A process as claimed in any one of claims 1 to 6 wherein the methyl or ethyl ester of the carboxylic acid is used in excess over the m-phenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative. 8. A process as claimed in claim 7 wherein from 1.05 to 1.20 moles of methyl or ethyl ester of the carboxylic acid are used per mol of m-phenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative. 9. A process as claimed in any one of claims 1 to 8 wherein the carboxylic acid is a 2,2-dimethylcyclopropane carboxylic acid which gives insecticidal esters with mphenoxybenzyl alcohol or its a-cyano or a-ethinyl derivative. 10. A process as claimed in claim 9 wherein the upper part of the skirt has, at its lower extremity, a bead comprising an outer layer and an inner layer which are integral and continuous with the upper part of the skirt, the free edge of the bead being located above the lowermost edge of the bead and being connected through the said bridges to the lower part of the skirt, and the outer and inner layers of the bead and the lower part of the skirt are all substantially parallel with the axis of the closure, whereby the bead forms a mask for the ragged edge on the upper part of the skirt which is created by rupturing of the bridges. 2. A closure according to Claim 1 wherein the peripheral slit line is so located that on rupturing of the bridges the ragged edge on the upper part of the skirt is disposed between the opposite ends of the bead. 3. A closure according to Claim 1 or Claim 2 wherein the outer layer of the bead is provided with knurling. 4. A closure according to any one of the preceding Claims, wherein the bead is offset outwardly from the upper part of the skirt. 5. A closure according to any one of Claims 1 to 3, wherein the bead is formed inwardly of the upper part of the skirt and the upper portion of the lower part of the skirt is offset inwardly to accommodate the bead. 6. A closure according to any one of Claims 1 to 3, wherein the bead is formed inwardly of the upper part of the skirt and the whole of the lower part of the skirt is correspondingly offset inwardly of the upper part of the skirt. 7. A method of forming a closure according to Claim 2 comprising the steps of: (a) folding outwards from the upper part of the skirt a two-sided bead one side of which is preferably substantially normal to the skirt and the other of which forms an acute angle with said one side, (b) forming a series of angularly spaced bridges interrupting a peripheral slit line in the skirt adjacent to and below said one side of the bead, and (c) at least partially collapsing the bead downwardly so that the bead extends down beyond the peripheral slit line and the outer and inner layers of the bead are substantially parallel with the axis of the closure. 8. The method according to Claim 7 including the step of setting the slits back substantially into the plane of the skirt before collapsing the bead downwardly. 9. The method according to Claim 7 or Claim 8 including the step of knurling the outer side of the bead while collapsing the bead. 10. A closure according to Claim 1 substantially as herein described with reference to Figures 1 to 7 or to8 or 9 of the accompanying drawings. handle at the operator's control station requires to be moved from the "OFF" position to the "START" position to create the first level of current through the relay, and then within the predetermined time interval the operator's handle requires to be moved from the "START" position to the "RUN" position to reduce the current through the relay 11 to a second level. It will therefore be appreciated that with such a modified relay an inadvertent interchanging of the Fig. 1 and Fig. 2 trailing cables at the machine end thereof will not result in energisation of a machine because the current through the modified relay does not alter in value unless the operator's station is in circuit and is operator actuated. Unfortunately the introduction of this modified form of switch box 10 reduces the level of standardisation in the mining environment and it is therefore possible for an operator to be confronted with a control station 16 which will start a particular machine merely by moving the control handle from the "OFF" position to the "START" position whereas if the same machine is connected by trailing cable to a modified switch box it will only start if the operator's handle is moved from "OFF" to START to "RUN" within certain time constraints. It is an object of the present invention to provide electrical control equipment in the form of an operator's control station which can be substituted for the known forms of operator control stations in order to promote standardisation and which is compatible with the two standard forms of switch box and the modified form of switch box discussed previously. According to the present invention there is provided electrical control equipment in the form of an operator's control station, comprising in combination a series circuit of a first contact which is normally open, a second contact which is normally open, a resistor, and diode, a timer device operating a first timer contact which is normally open and which is connected in parallel with said resistor, and a second timer contact which is normally closed and which is connected in parallel with said first contact, an an operator's handle movable between first,. second and third positions and coupled to operate said timer device and said first and second contacts, the arrangement being such that movement of said handle from said first to said second positions causes said timer contacts to change state for a time interval predetermined by said timer device, and causes said second contact to change state, and movement of said handle from said second to said third position causes said first contact to change state. It will now be appreciated that utilising the present invention two different levels of current through the relay can be achieved consecutively and within a predetermined time interval if the operator's handle of the control station is moved in sequence from first to second to third positions and then back again to the second position, provided that the handle is in the third position before expiry of the predetermined time interval. If the timer device fails to operate properly either the first level of current is not attained or the first level of current is maintained without the second level of current being attained so that the relay of the modified switch box referred to previously is not actuated. If the switch box contains a relay in the unmodified form i.e. of the Fig. 1 or Fig. 2 configurations it will be energised when the handle is moved into the third position provided the timer device is initially operational and if the timer device fails to change the state of the timer contacts after the predetermined time interval the relay will become de-energised when the handle is moved from the third position back to the second position. The present invention permits the use of various additional protective contacts which are already utilised in mining machinery. For example, normally-open contacts which close in response to oil pressure being attained at start-up of the machinery. Additionally, the conventionally utilised normally-closed contact which is timer operated to open can be accommodated to safeguard the machinery against the operator's handle being per manentlyjammed in the third position (which would defeat the protective contacts). An embodiment of the present invention will now be described with reference to Fig. 3 of the accompanying drawings. As previously discussed Figs. 1 and 2 illustrate known current arrangements and are intended herein for reference purposes. In Fig. 3 the first contact is denoted A, the second contact B, the reistor R is shown as being 30 ohms, the diode is E, and the timer device D has contacts D1 and D2. The operator's handle is not shown but the table accompanying Fig. 3 denotes the condition or state of the various contacts in relation to the position of the handle. The conventional oil-pressure operated protective contacts are denoted P and the conventional timer safeguard contact is C which performs its normal function of breaking the circuit if the handle is maintined for too long in the third position. Conveniently, the first handle position is denoted "OFF"; the second handle position "RUN"; and the third handle position "START". WHAT WE CLAIM IS 1. Electrical control equipment in the form of an operator's control station, comprising in combination **WARNING** end of CLMS field may overlap start of DESC **. WHAT I CLAIM IS:- 1. A balance arrangement for a reciprocatory mechanism comprising a main operating arm which controls reciprocal operation of a stamping, pressing or forming tool, and an additional operating arm which controls reciprocal operation of a feed mechanism for feeding sheet material synchronously into the path of the tool, and a balance weight drivingly interconnected with the main operating arm and the additional arm by pivotal linkages whereby, during operation, the balance weight moves in the opposite sense about a support shaft to the movement of the operating arms about a support shaft. 2. An arrangement according to claim l, wherein the pivotal linkages include a pair of cranks, the one arms of each pair of cranks being secured in diametrically opposite positions about a drive shaft, whilst the other arms of each pair of cranks are connected for driving the operating arms and the balance weight respectively, 3. An arrangement according to claim 1 or claim 2, wherein the support shaft for the balance weight is also the support shaft for the operating arms. 4. An arrangement according to any one of claims 1 to 3, wherein a plurality of further operating arms for driving further parts of the mechanism reciprocably are interconnected for coincidental movement about the support shaft for the main and additional operating arms. 5. An arrangement according to any one of claims 1 to 4, wherein the balance weight is a bar-like member whose axis extends parallel with the support shaft axes. 6. An arrangement according to any one of claims 1 to 5, wherein each operating arm comprises a coupler and a lever connected to the reciprocable part of the mechanism. 7. A balance arrangement substantially as herein described with reference to the accompanying drawings. thickness is disposed in the region of an annular shoulder at the said one end of the container casing. 3. A dispensing container according to Claim 2, wherein the zone of reduced wall thickness is located in a cylindrical part of the annular shoulder. 4. A dispensing container according to any one of Claims 1 to 3, wherein the outlet nozzle member can be fitted directly onto the cylindrical casing. 5. A dispensing container according to Claim 4, wherein the outlet nozzle member is adapted to be fixed to the container casing by means of a snap-action device comprising circumferentially extending projections formed on a body part of the nozzle member and the casing respectively, the projection on said body engaging behind the projection on the casing. 6. A dispensing container according to Claim 5, wherein the projection on the casing and/or the projection on said body part is formed by one side of an annular groove in the container casing or body part of the outlet nozzle member respectively. 7. A dispensing container according to Claim 5, wherein the said projection on the casing is constituted by a bead-like seam by which an end cover providing the removable wall is connected to the container casing. 8. A dispensing container according to any one of Claims 1 to 7, wherein there is extending about the radially outer edge of the other end wall of the container an annular zone of reduced wall thickness which allows said other end wall to be torn away from the container casing. 9. A dispensing container according to Claim 1 or Claim 8, wherein the zone of reduced wall thickness is disposed adjacent or within an annular corrugation formed in such end wall of the container. 10. A dispensing container substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 6 or in Figures 7 to 11 of the accompanying drawings. 37 in the claw. The spring 32 urges the clamping claw 22 into its clamping position, in which the trailing edge 10a of the screen is clamped between the flat lower surface of the tongue 24 of the claw and the flat upper surface of the portion 20a of the bar 20. The clamping claw is undercut beneath the tongue 24 to give more freedom for tolerances in the screen size without danger of the claw pulling on the edge of the hole in the screen or missing it altogether. In Figures 3 and 4 recessed portions 38 of the lower surface of the bar 20 are formed to receive the longitudinally spaced plates 29 (Figure 2). Figure 3 also shows the apertures 34 for the passage of the clamping claws and the section shown in Figure 6 passes through such an aperture and through a tapped hole 36 for the spring-retaining screw. As each claw is urged closed by a separate spring, all claws exert an effective clamping action without requiring tight tolerances on their angular position on the shaft. The location of the rod in the V-shaped groove provided in the clamp body reduces tolerance and alignment problems. The rod is retained by a bearing block at each end of the clamping bar and by two intermediate retaining plates. With a clamp assembly of the kind described the only extra requirement for the drum is the provision of a groove to receive the assembly. Figure 7 shows an alternative form of clamp utilising a torsion spring 40 to hold the claw 22 in its clamping position, in place of the compression spring 32 shown in Figure 2. WHAT WE CLAIM IS: 1. A screen clamp for fixing the trailing edge of a printing screen on a cylinder, comprising: a bar for location in a recess in the cylinder surface and parallel to the cylinder axis, the bar being shaped to provide a longitudinal groove in one bar surface. for location at the base of the recess in the cylinder; a rod seating in the longitudinal groove, the cross-sectional shape of the bar and the diameter of the rod being such that the rod makes line contact with the bar on two sides of the groove; and a number of longitudinally spaced clamping claws pivotally mounted on the rod and extending through apertures in the surface of the bar opposite the grooved surface, the portion of each claw which extends through the aperture having a tongue which extends over the bar surface adjacent the aperture, the claw being resiliently mounted so that the trailing edge of the screen, placed around the cylinder and provided with apertures for the passage of the claws, is clamped between the bar surface and the said tongues. 2. A screen clamp in accordance with claim 1 in which the said groove is V-shaped, the rod making line contact with each side of the groove. 3. A screen clamp in accordance with claim 1 or 2, comprising, for each claw, a spring acting in a direction such as to close the tongue of the claw on the bar surface. 4. A screen clamp, for fixing the trailing edge of a printing screen on a cylinder, substantially as herein described with reference to the accompanying drawings. **WARNING** end of CLMS field may overlap start of DESC **. WHAT WE CLAIM IS: 1. An apparatus for the production, filling and sealing of bags, comprising a bag station at which bags are formed, and a transfer device which delivers the bags to two adjacent conveyors, each of which is provided with a filling station, a sealing station and a transfer or delivery station, wherein the conveyors are formed by two chain-conveyor tracks extending side by side and wherein the transfer device comprises an intermediate magazine which is displacefl able in timed manner transversely to the conveying direction and which displaces the bags received individually from the bag station, alternately on either side for transference respectively to a chain-conveyor track. 2. An apparatus as claimed in claim 1, wherein scraper devices for moving the bags into and out of the intermediate magazine are provided in each case at the position of acceptance by the intermediate magazine and at the two transfer positions to the chain-conveyor tracks. 3. An apparatus as claimed in claim I wherein the intermediate magazine comprises two commonly transversely displaceable, upwardly and downwardly open receiving shafts for the bags. 4. An apparatus as claimed in claim 1 wherein the intermediate magazine is driven through a rack by a pinion which simultaneously drives an intermediate magazine of another apparatus, preferably of similar design, for the production, filling and sealing of bags, likewise through a rack. 5. An apparatus as claimed in claim 4 wherein the pinion is drivable by means of a control cam and a cam follower for limited rotating movements. 6. An apparatus as claimed in claim 4 wherein the chain-conveyor tracks and both intermediate magazines are in drive connection with one another through a common main control shaft. 7. An apparatus as claimed in claim 4 wherein the intermediate magazines of the two apparatuses are individually uncouplable according to choice. 8. An apparatus for the production, filling and sealing of bags substantially as hereinbefore described with reference to and as shown in the accompanying drawings. ZUPACK-GESELESCHAFT M.B.H., Per: BOULT, WADE & TENNANT, 27 Furnival Street, affected if the end pipe section thereof were to break surface through wave-motion. Finally, the use of a suction pump would tend to emulsify the oil as it passed through the pump and thereby hinder separation of the oil and water in the separator vessel. Such emulsification does not tend to occur with the use of a jet-nozzle unit as described. It will be appreciated that the abovedescribed process can be used to separate any two immiscible fluids of different specific gravities and is not limited to oil and water. The apparatus can be made to any convenient, appropriate scale and either fitted in a fixed location or mounted on a vehicle or ship as described, for transportation. It is also envisaged that for large scale apparatus more than one jet-nozzle unit could be used to supply the separator vessel. WHAT WE CLAIM IS: 1. A method of separating a mixture of two immiscible fluids of different specific gravities comprising the steps of: supplying a first container with the fluid mixture; permitting the fluids to separate by gravity sep- aration; whilst still supplying the fluid mixture to the first container, allowing the lower density fluid to overflow from the first container into a second container and removing the higher density fluid from the bottom portion of the first container; detecting when the interface between the fluids is close to the area of overflow of the lower density fluid and halting the supply of fluid mixture to the first container whilst continuing to remove the higher density fluid therefrom; and detecting when the interface between the fluids is close to the bottom portion of the first container and halting the removal of the higher density fluid there from. 2. A method as claimed in claim 1 in which the lower density fluid is allowed to overflow from an open top of the first container into the second container until the interface between the fluids is close to the open top when the sup liy of fluid mixture to the first container is halted. 3. An apparatus for separating a mixture of two immiscible fluids of different specific gravities comprising a separator vessel with two communicating compartments defining first and second containers, the first container being provided with a fluid inlet and a fluid outlet located in a bottom region thereof and the second container communicating with the first container in an upper region of the latter whereby fluid can overflow from the first container into the second container, supply means to supply the fluid mixture to the first container via its fluid inlet wherein the fluids can separate by gravity separation and from whence the lower density fluid can overflow into the second container and the higher density fluid can be removed from the first container via its fluid outlet, and sensing control means for detecting the level of the fluid interface within the first container and accordingly either halting the supply of the fluid mixture to the first container when the fluid interface is close to the area of overflow of the lower density fluid from the first container or halting the removal of the higher density fluid from the first container when the fluid interface is close to the bottom portion thereof. 4. An apparatus as claimed in claim 3 in which the supply means comprises an inlet pipe with a venturi and a jet-nozzle for supplying pressurised fluid to the venture. 5. An apparatus as claimed in claim 4 in which the pressurised fluid is supplied to the fluid inlet of the first container by a Dump. 6. An apparatus as claimed in claim 4 or 5 in which the control sensing means comprises a probe disposed within the first container and able to initiate the opening or closure of a valve situated upstream of the venturi in the inlet on detection of the fluid interface. 7. An apparatus as claimed in claim 6, in which the control sensing means comprises two of said probes, an upper one of which is disposed below the area of overflow of the lower density fluid from the first container and is able to initiate closure of the valve, and the other lower one of which is disposed close to the bottom of the first container and able to initiate opening of the valve. 8. An apparatus as claimed in any one of claims 3 to 7 in which the first container is disposed substantially within the second container and has an open top to allow overflow of the lower density from same into the second container. 9. An apparatus as claimed in claim 8 when dependent on claim 7 in which the first container has a relatively narrow neck below the open top and the said upper probe is centrally disposed therein. 10. An apparatus as claimed in any one of claims 3 to 9 in which a perforated screen is disposed across the interior of the first container to reduce turbulence of the fluid mixture therein. 11. An apparatus for separating a mixture of two immiscible fluids of different specific gravities substantially as hereinbefore described with reference to the accompanying drawings. 12. A method for separating a mixture of two immiscible fluids of different specific gravities substantially as hereinbefore described with reference to the accompanying drawings. **WARNING** end of CLMS field may overlap start of DESC **. through a respective aperture extending through the post so that the post supports the members. 2. A plant support as claimed in Claim 1, wherein two of said members are provided and the apertures are grouped in adjacent pairs, one for each of the members. 3. A plant support as claimed in Claim 2, wherein the axes of the apertures for said members are generally parallel to one another. 4. A plant support as claimed in Claim 2 or 3, wherein the helical portion of said members wind in opposite directions as they extend along the post. 5. A plant support as claimed in any one of the preceding claims, wherein one of the ends of the post is provided with a longitudinal hole, each of said members having a portion extending from that one of the apertures therefor which is nearest said one end of the post and terminating in an end portion located in said hole. 6. A plant support as claimed in any one of the preceding claims, wherein the members are made of plastics material. 7. A plant support as claimed in any one of the preceding claims, wherein the members are flexible. 8. A plant support as claimed in any one of the preceding claims, wherein the post is formed from a plurality of interlocking pieces. 9. A plant support substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. respectively. A rectangular auxiliary base frame member 6 is pivotably mounted to the side frame member 4 by means of loop hinges 7. The frame member 4 is fixedly secured to the base member 1 to form a substantially rigid basic framework. The frame member 5 is detachably mounted on the sub-frame 3 in any conventional manner. The frame member 4 is provided with studs 8 projecting outwardly of the load-containing space of the pallet. The frame member 5 has key-hole slot members 9 secured to it to enable it, when detached from the sub-frame 3 to be mounted in an upright manner on the frame member 4 (as seen in Fig. 2). The auxiliary base frame member 6 can be pivoted between a flat load-carrying position on the base member 1 and an upright nesting position adjacent frame member 4. The latter is provided with a catch 10 which serves to retain the auxiliary base frame member in its upright position when desired. It is to be noted that the sub-frame 3 provides a wheel base that is sufficiently narrower than that at the broader end of the base member to allow the sub-frame 3 to pass between the wheels at the broader end of the base member of a second said pallet. Thus, in use, although the pallet is of conventional rectangular base and side frame shape when used for carrying loads (Fig. 1), the frame member 5 and auxiliary base frame member 6 can be moved to their "nesting" positions (Fig. 2) and the pallet can then be nested with similar pallets as shown. in Figs. 6 and 7. It will be seen that the tapered base member 1 of each nesting pallet (except for those at the ends) nests within the tapered base member 1 of the adjacent pallet in front and receives the base member 1 of the adjacent pallet behind. Clearly, in the embodiment described above, the frame member 4 must be arranged to provide sufficient clearance below to receive the base member 1 of another pallet (see Fig. 3). The trapezoidal base member may be sufficiently tapered to resemble a V-shape without departing from the trapezoidal shape of the wheel base. Referring to Figs. 8 to 10, there is shown a preferred form of pivotal connection of an auxiliary base frame member 60 to a side frame member 70 according to the present invention and suitable for incorporation in the pallet of Figs. 1 to 7. The auxiliary base member 60 has two aligned cylindrical sockets 61, 62 the latter of which has a flange 63 in the form of a collar in which a gap 64 is provided. The side frame member 70 has two aligned pins 71, 72 secured at their right hand ends (as seen in the drawings) to a cross-bar 73 of the side frame member 70 by means of flat spacers 74. A key 75 is provided on the crossbar adjacent the left hand end of the pin 72. The auxiliary base member 60 can be mounted on and removed from the side frame member 70 by sliding the sockets 61, 62 on to or off the pins 71, 72 respectively. However, this can only be done when the key 75 is aligned with the gap 64 which serves as a keyway therefor and this is arranged to occur when the auxiliary base member 60 is pivoted relative to the member 70 to a position intermediate the load-carrying and nesting positions. WHAT WE CLAIM IS

1. A wheeled pallet having a wheeled base member, a side frame member and an auxiliary base member pivotably mounted so as to be pivotable relative to the side frame member between a load-carrying fiat position on the wheeled base member and an upright position adjacent the side frame member, the pivotal mounting between the auxiliary base member and said side frame member being provided by an arrangement of aligned pins rotatably engaging sockets, the pins being longitudinally slidable relative to the sockets for withdrawal therefrom to permit removal of the auxiliary base member from the pallet, only at an intermediate position of the auxiliary base member intermediate the load-carrying flat position and the upright position.

2. A wheeled pallet according to claim 1 wherein said intermediate position is defined by means of a co-operating key and keyway gap associated with the auxiliary base member and said side frame member

3. A wheeled pallet according to claim 1 or claim 2 wherein the pins are provided on the side frame member and the sockets on the auxiliary base member.

4. A wheeled pallet according to claim 2 or claim 3 when dependent on claim 2 wherein a key is provided in proximity to one of the pins and the respective socket is provided with a collar having a gap serving as a keyway for said key, said key serving as an axial stop member with respect to said collar when said break providing said keyway is not aligned therewith.

5. A wheeled pallet according to claim 1 having an auxiliary base member and pivotal mounting therefor substantially as described hereinbefore with particular reference to Figs. 8 to 10 of the accompanying drawings.

**WARNING** end of CLMS field may overlap start of DESC **.

**WARNING** start of DESC field may overlap end of CLMS **.

respectively. A rectangular auxiliary base frame member 6 is pivotably mounted to the side frame member 4 by means of loop hinges 7.

The frame member 4 is fixedly secured to the base member 1 to form a substantially rigid basic framework. The frame member 5 is detachably mounted on the sub-frame 3 in any conventional manner. The frame member 4 is provided with studs 8 projecting outwardly of the load-containing space of the pallet. The frame member 5 has key-hole slot members 9 secured to it to enable it, when detached from the sub-frame 3 to be mounted in an upright manner on the frame member 4 (as seen in Fig. 2).

The auxiliary base frame member 6 can be pivoted between a flat load-carrying position on the base member 1 and an upright nesting position adjacent frame member 4.

The latter is provided with a catch 10 which serves to retain the auxiliary base frame member in its upright position when desired.

It is to be noted that the sub-frame 3 provides a wheel base that is sufficiently narrower than that at the broader end of the base member to allow the sub-frame 3 to pass between the wheels at the broader end of the base member of a second said pallet.

Thus, in use, although the pallet is of conventional rectangular base and side frame shape when used for carrying loads (Fig. 1), the frame member 5 and auxiliary base frame member 6 can be moved to their "nesting" positions (Fig. 2) and the pallet can then be nested with similar pallets as shown. in Figs. 6 and 7.

It will be seen that the tapered base member 1 of each nesting pallet (except for those at the ends) nests within the tapered base member 1 of the adjacent pallet in front and receives the base member 1 of the adjacent pallet behind. Clearly, in the embodiment described above, the frame member 4 must be arranged to provide sufficient clearance below to receive the base member 1 of another pallet (see Fig. 3).

The trapezoidal base member may be sufficiently tapered to resemble a V-shape without departing from the trapezoidal shape of the wheel base.

Referring to Figs. 8 to 10, there is shown a preferred form of pivotal connection of an auxiliary base frame member 60 to a side frame member 70 according to the present invention and suitable for incorporation in the pallet of Figs. 1 to 7.

The auxiliary base member 60 has two aligned cylindrical sockets 61, 62 the latter of which has a flange 63 in the form of a collar in which a gap 64 is provided.

The side frame member 70 has two aligned pins 71, 72 secured at their right hand ends (as seen in the drawings) to a cross-bar 73 of the side frame member 70 by means of flat spacers 74. A key 75 is provided on the crossbar adjacent the left hand end of the pin 72.

The auxiliary base member 60 can be mounted on and removed from the side frame member 70 by sliding the sockets 61, 62 on to or off the pins 71, 72 respectively. However, this can only be done when the key 75 is aligned with the gap 64 which serves as a keyway therefor and this is arranged to occur when the auxiliary base member 60 is pivoted relative to the member 70 to a position intermediate the load-carrying and nesting positions.

WHAT WE CLAIM IS