GB2235256A

GB2235256A - Flexible chamber pump

Info

Publication number: GB2235256A
Application number: GB9013713A
Authority: GB
Inventors: Thomas John Mcneel Robertson
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-06-22
Filing date: 1990-06-20
Publication date: 1991-02-27
Also published as: DE4019594A1; GB9013713D0; FR2648871A1; GB8914369D0; NO902765L; NO902765D0; JPH0396663A

Abstract

A flexible chamber pump comprises three flexible members (63, 64, 65) movable by fluid pressure in a sequence so that fluid passes through a casing (54) having ports (55, 56) for the entry and exit of the fluid. The outermost members perform a valving function which ensures a uni-directional flow through the casing. Electromagnetic coils (E) are energised to apply a magnetic force to pistons (A), the resulting motion causing fluid to be displaced through respective ports (X) into contact with the flexible members. The coils may be arranged to cause the pistons to be rotated, the rotation being converted into longitudinal movement by peripheral screw threads on the pistons meshing with complementary threads in the cylinder bores. Alternatively the actuating fluid may be oscillated by liquid columns which pass out of the casing to piston and cylinders operated by cam or crankshaft mechanisms. In another arrangement a rotary distributor supplies the fluid to the flexible members in the required sequence. Other embodiments are described wherein the flexible members are in the form of inflatable balloons located in a cylindrical or conical casing. <IMAGE>

Description

PUMPS 1 Mixtures of different or variable compositions may require to be

pumped, e.g. pumpable mixtures from oil wells or available in the oil industry, for instance in handling, manufacturing, processing, or refining operations. Such pumping may take place off shore (e.g. from a well under sea water or on board an off shore installation or a tanker), or on shore (e.g. in respect of pipeline transmission or manufacture of oil products). An example of a pumpable variable mixtiire is a com-position comprising gas(es), liquid hydrocarbon(s), and optionally particulate solid(s), etc. If pumpable variable mixtures contain particulate solid material(s), the solids may cause abrasion or other damage in reciprocating or rotary pumps. Turbulences in mixtures being pumped may cause stable emulsions to form in reciprocating or rotary pumps. A further problem is that'sudden changes in proportions of components of pumpable variable mixtures may present difficulties for rotary pumps, because of mechanical stresses arising from changes in inertias possessed by different densities of the components.

It has been found that at least one of the above problems may be prevented or reduced by using a pump provided in accordance with the present invention. Such a pump may be termed (for convenience of description) an endostaltic or obturation pump. The pump may therefore be regarded as being different from a peristaltic pump. In a peristaltic pump, the pumpable material is completely enclosed by a pump surface that will undergo peristalsis, In an endostaltic pump, the pumpable material is between at least two separate pump surfaces whereby obturation between those surfaces enables pumping. The invention's pump may produce flows and pressures for many applications, e.g. as mentioned in the first paragraph above, for instance in the range -1 Bar to +35 Bar.

According to a first aspect of the present invention, a pump for pumpable fluld(s) comprises:

(a) a container having at least one Inlet and at least one outlet; (b) at least one reducible chamber in said container, said chamber being communicatable with said at least one inlet arid said at least one outlet, said chamber having at least one displaceable chamber boundary to contract or expand capacity of said chamber; (c) at least one tensible displacer means for displacing said at least one displaceable chamber boundary so as to contract or expand said chamber, the expansion enabling said chamber to be at least partly charged with displaceable fluld(s) from said at least one inlet, the contraction enabling said chamber at least partly to discharge displaceable fluids(s) therefrom; (d) at least first valve means for resisting flow 20 pumpable fluid(s) Into said chamber, the resisting being in a flow path from said at least one Inlet; (e) at least one second valve means for resisting flow of pumpable fluld(s) Into said chamber, the resisting being in a flow path from said at least one outlet.

According to a second aspect of the present invention, pump apparatus comprises:

at least one pump according to the first aspect of the invention; and at least one control means for controlling displacement(s) of at least one tensible displacer means (c).

The pump may be embodied In any suitable manner, e.g. for any suitable material(s) and for any suitable application(s) of the pump. At least one pump may be connectable to any suitable source of pumpable fluid.

1 Container (a) may be at least a portion of the exterior and/or at least a portion of the Interior of the pump. An example of a said outer container is a casing.

An example of a said inner container Is a liner. In general, container (a) may have any suitable configuration andlor shape, e.g. tubular. Container (a) may be at least partly flexible (e.g. resilient) and/or at least partly rigid, relative to displacement action(s) provided by said at least one tensible displacer means.

Chamber (b) may have any suitable configuration and/or shape. At least one chamber boundary may be constituted by container (a). At least. one said displaceable chamber boundary may be constituted by at least one said tensible displacer means (c). Contraction of the chamber may reduce the capacity of the chamber to any suitable reduced capacity, e.g. zero capacity, thereby corresponding to an at least partly discharged mode of the chamber. In general, the chamber may be closed, open, or throttled relative to the general flow path required from said at least one inlet to said at least one outlet. In one example, the pump comprises: chamber (b) consituted by container (a), a first tensible displacer means (c) disposed relative to said at least one Inlet, a second tensible displacer means (c) disposed relative to said at least one outlet, and a third tensible displacer means (c) between said first and second displacer means at least two of the first, second, and third tensible displacer means (c) may be the same or different kinds of displacer means, e.g. first, second, and third tensible envelopes (see below). Any change may be Introduced as required by any application, so as to reduce turbulance in the pumped fluid or to Induce at least one component of motion Into pumpable fluid(s) In chamber (b), e. g. to provide flow pattern(s) andlor agitation and/or mixing in the fluld(s).

in general. relative to contraction or expansion of chamber (b), the corresponding "contraction time" for 5 contraction of chamber (b) may have any suitable value, e.g. be the same as or different from the "expansion time" for expansion of chamber (b)- The expansion time may be substantially shorter than the contraction time. The ratio (contraction time)l(expansion time) may be regarded as a coefficient or restitution for chamber (b).

Tensible displacer means (c) may have any suitable configuration and or shape. At least one tensible displacer means (c) may constitute at least one said displaceable chamber boundary. Tensible displacer means (c) may be a single or a composite displacer. The tensility or tensile strength of tensible displacer means (c) may be sufficient to revoke at least partly said displacing when expanding of chamber (b) is to occur.

Somn tensible displacer means comprise at least one tensible elastic or non-elastic envelope, [(e.g.

comprising membranes)]. A tensible envelope may comprise at least one balloon or balloon portion, or bellows or bellows portion, expandable to have any suitable shape(s).

The ratio (maximum volumeMminimurn volume) for a tensible envelope may be regarded as a coefficient of resitution corresponding to that for chamber (b). A tensible envelope may have a preformed convoluted shape when e.g. not made of elastic material, or In general any suitable shape dependant on Its material, before, during, or after tensioning.

The pump or pump apparatus may comprise at least one actuation means for actuating at least one tensible displacer means (c). An example of actuation means Is pressure fluid actuation means for utilising pressure application fluid(s). e.g. a gas or hydraulic fluid, for aiding or enabling said actuating. Another example of actuation means is magnetic actuation means for uttlising magnetic foree(s) for aiding or enabling said actuating. A further example of actuation means is motor actuation means for utilising motor(s) for aiding or enabling said actuating. Reduction or removal of actuating force provided by at least one said actuation means may result in the tensility of at least one said displacer means revoking at least a portion of said displacement thereof.

First valve means (d) may enga.ge at least one said inlet. First valve means (d) may be constituted by at least one first tensible displacer means (c).At least one first tensible displacer means (c) may be displaced to seal al,,airist cont.ii.ner (a), e.g. a said first tensible envelope may expand to obturate or occlude flow path(s) between said at least one inlet and chamber (b).

3econd valve means (e) may engage at least one said outlet. Second. valve means (e) may be constituted by at least one second tensible displacer means (c). At least one second tensible displacer means (c) may be displaced to seal against container (a), e.g. a said second tensible envelope may expand to obturate or occlude flow path(s) between said at least one outlet and chamber (b).

It will be appreciated tha.t at least one third tensible displacer means (c) may be displaced to seal al.,,ainst container (c), e.g. a said third tensible envelope may expand to obturate or occlude flow path(s) between said first and second displacer means (c), thereby constituting third valve means (f).

Any said valve means may be adapted for unidirectional flow of pumpable fluid(s) in the general flow path from said at least one inlet to said at least one outlet.

0aid control means may comprise at least one coml)uter control means and/or any other timing control means, and flow distribution means (e.g. pipes and/or valves for pipes).

rumpable fluid(s) may be compressable or non-compressable. Pumpable fluids may comprise at least one component selected from: gases, liquids, and particulate solids capable of being fluidised. Some pumpable mixtures are two'phase gas/liquid mixtures in any proportions, e.g. a mixture of gaseous and liquid hydrocarbons obtained from an oil well, optionally containing other liquid(s), for instance brine or sea water. Some other pumpable mixtures are three phase gas/liquid/solid mixtures, e.g. a said two phase mixture containing sand and/or other particulate solid(s). Some further pumpable mixtures are water, refrigerants, sludges, and slurries. Fluids or mixtures of fluids may contain dead and/or living organism(s), e.g. cultures or blood cells.

Pumped fluids discharged from pumps of the present invention may have any suitable discharge pressure(s), e,g subs tniltially +35 Bar.

as to reduce any risk of mixture.

in the range substantially -1 Bar to Pumping may be condiicted so churninL, of an emulsifiable In the accompanying drawings, which are by way of schematic example of the present Invention:

Fig. 1 shows a pump apparatus comprising tensible, elastic resilient balloons.

Fig. 2 shows a pump apparatus comprising other tensible, elastic balloons.

Fig. 3 shows a tensible, preformed convoluted envelope that is not of elastic material.

Fig. 4 shows a pump apparatus comprising tensible displaceable membranes.

Fig. 5 shows a pump apparatus for use as a gas compressor.

Fig. 6 shows a pump apparatus having balloon valves in its 15 general pumping flow path.

Fig. 7 shows a pump apparatus having conventional nonreturn flow valves in its general pumping flow path.

Fig. 8A, BB show a magnetically operated driver for pump apparatus.

Fig. 9 shows a closed cycle cooler containing a pump apparatus.

Fig. 10 shows an open cycle cooler and water purifier. Fig. 11 shows a pump appraratus having three electromagnetic actuation means each having a displacer piston for enabling fluid flows to displace respective portions of a tensible elastic flexible tube.

Fig. 12 shows two electromotor actuation means for providing longitudinal and rotary motions of respective displacer pistons.

Fig. 13 shows a modified pump apparatus corresponding to Figs. 2 and 11, wherein corresponding reference numerals relate to similar portions of pump apparatus.

In Fig. 1, rigid, cylindrical casing 1 has an inlet 2 and an outlet 3 at opposite ends thereof. Inside casing 1, a tensed elastic flexible balloon 4 is adjacent inlet 2, a tensible elastic flexible balloon 5 is adjacent outlet 3, and a tensible elastic flexible balloon 6 is between balloons 4 and 5, thereby constituting reducible chamber C. The expansion shown of balloons 4 and 5 occludes the general flow way F extending between inlet 2 and outlet 3. Thus, balloon 4 is an inlet valve for chamber C, and balloon 5 Is an outlet valve for chamber C, these valves being able to gate the flow way F. Balloon 6 may be expanded to occlude the flow way F, thereby reducing capacity of chamber C. Balloons 4,5,6 may be expanded by inflating them with the fluid (e.g.

gas or hydraulic fluid) from corresponding pressurising lines 7,8,9 comprised by control means 10, which may include computer control means and valve means (not shown) for controlling the supply of pressurising fluid to, or withdrawal of therefrom, the balloons. Withdrawal of e.g pressurising gas from any balloon results in the tensility of the balloon contracting -the balloon. Contraction of balloon 4 enables contraction of balloon 6 to suck into expanding chamber C fluid from inlet 2 when balloon 5 is in sealing contact with casing 1. Expansion of balloon 6 when balloon 5 is contracted and balloon 4 is in sealing contact with casing 1 results in contraction of chamber C and thereby discharge therefrom of fluid via outlet 3. It will be appreciated that discharge of the pressurising fluid from any balloon to a void or reduced pressure region (e.g.a chamber) substantially below the pressure in reducible chamber C will aid contraction of the balloon. This discharge is an option that may be of advantage in priming a pump and or inducing flow of viscons fluid(s) into the pump, especially if a tensible i displacer means comprises a displaceable membrane.

In Fig. 2, a rigid cylindrical casing 21 has an inlet 22 and an outlet 23 at opposite ends thereof. Inside casing 21, a cylindrical manifold or plenum 24 has a 5 tensible tube 25 closely fitting the exterior of plenum 24. Tube 25 is circumferentially fixed at attachment zones 26,27,28,29 on the exterior of plenum 24, the fixings constituting nodes for enabling tensible balloon portions 34,35,36 to be defined by tube 25, these portions being expandable by supply of pressurising fluid (e.g. gas or hydraulic fluid) from respective supply lines 37,38,39 comprised by plenum 24. Balloon portions 34,35,36 are in respective ones of reducible chambers respectively comprising concave interior profiles of casing 21.

Nw, 111,1X111111M of' each chamber is centrally located of the length of each chamber, thereby minimising clearance or unswept volume of the pump. The concavity of each chamber may correspond to the natural shape taken by the corresponding balloon portion.

The concavity of a chamber may have an axial profile that is a parabola defined by:

y = K x 2 12 wherein y is the axial distance from a node of the chamber, x is the internal width of the chamber at that distance, and K is a constant determined by operating characteristics of the pump and by the elasticity (tensility) of the tube material. Such a profile will tend to reduce the strain on the wall of tube 25.

Supply of pressurising gas to the balloon portions 34,35,36 (which are similar to balloons 4,5,6, of Fig. 1) is from corresponding pressurising lines 37,38,39 comprised by control means 40, which has pistons 41,42,43 respectively corresponding to those lines.

The pistons are mounted on rotatable crankshaft 44 having three corresponding "throws" angularly displaced 1200 between adjacent "throws". If a pressurising fluid is non-coinpressible (e.g. a hydraulic fluid), gas/liquid accumulators (not shown) may be provided one in each pressurising line, and/or spring-loaded telescoping connecting rods may be -connected to the "throws". The crankshaft may be rotated by any suitable means, e.g. an electrical motor or an internal-combustion engine.

Crankshaft 44 may be an actual component of a motor or engine. Crankshaft 44 may be replaced by rams (not shown) for driving the pistons. Means (not shown) may be provided for enabling a dwell or rest period for operating each pressurising line, so as to give timing overlap between successive expansions of the balloon portions.

In Fig. 3, a casing 1 contains a reducible chamber C in which is a tensible, preformed, sufficiently rigid envelope 2 that is not of elastic material. Envelope 2 is an alternative to a tensible elastic flexible balloon in Fig. 1.

In Fig. 4, a cylinder 1 is rotatable about a longitudinal axis XY by any suitable means (not shown). The inner wall of cylinder 1 has a continous grooved track 2 that is a ball race for ball bearings B seated in respective circumferential grooves 3,4,5 in the outer walls of cylindrical, hollow plungers 6,7,8 and held therein by a carrier sleeve 9 having apertures through which the ball bearings project into ball race 2, portions of which are circumferential and portions of which are inclined to axis XY. Plungers 6,7,8 are closed at their upper ends but have respective glands 10,11,12 at their lower ends through which sealingly pass respective pipes 13,14,15 communicating with the corresponding hollow interiors of the plungers. These sealing fits are such i 1 1 that when cylinder 1 is rotated, ball bearings B enable ascent or descent of plungers 6,7,8 sequentially, the ascents corresponding to pressurising gas passing into the cylinders from pipes 13,14,15, and the descents corresponding to pressurising gas passing from plungers 6,7,8 into those pipes, which lead to respective pressurising chambers Pl,P2,P3 contiguous with the upper faces of displaceable membrances 16,17,18 within hemisplierical housings 19,20,21. The lower faces of membranes 16,17,18 are contiguous with pumping chambers Cl,C2,C3 that are sequentially connected together by pipes 22,23,24,25 defining a general pumping flow path from inlet end 22a of pipe 22 to outlet end 25b of pipe 25, whereby suitable operation of plungers 6,7,8 enables fluid to be pumped from inlet to outlet via the reducible chambers Cl,C2,C3 in accordance with displacements of membranes 16,17,18 in response to the pressurising gas.

In Fig. -5, rigid, tapered casing 1 converges from pump inlet 2 to pump outlet 3 comprised by the casing. Within casing 1 is a tensible tube 5 similar to tensible tube 5 in Fig. 2, providing balloon portions 14,15,16,17 similar to the balloon portions 34,35,36 in Fig. 2, in corresponding reducible chambers comprising tapered interior profiles of casing 1.

In Fig. 6, a rigid spherical casing 1 contains an elastic flexible tensible balloon 2 in a reducible chamber C, which can be expanded or contracted in accordance with Fig. 1, Fig. 2, or Fig. 4, suitably modified. In pump line 3 (which defines the general pumping flow path) is an elastic flexible tensible balloon input valve 4 to gate line 3. An elastic flexible resilient balloon 5 in pump line 3 is an elastic flexible tensible balloon outlet valve to gate line 3. Expansion or contraction of balloons 2,4,5 are controlled by suitable control means (not shown) which may be similar those of Figs. 1,2,4, e.g. control means 10 of Fig. 1.

In Fig. 7, the inflatable balloon valves 3,5 of Fig. 6 are shown replaced by conventional flap valves 6,7 5 respectively.

In Figs 8A,8B, an electromagnetic driver 1 is shown suitable for rotating shaft 44 in Fig. 2 or rotating casing 1 in Fig. 5. Driver 1 has a rotor 2 driven by an electric motor (not shown). Rotor 2 has alternate permanent magnet segments N,S^S providing respective north and south magnetic poles for attracting or repelling the magnetic poles of the magnetic shoes 3,4,5,6 arcuately disposed around the rotor 2 but spaced apart. Rotor 2 as it rotates gives a low friction actuating system taking advantage of back EMF generated in electric motors, and safeguarding the rotating electric motor from stalling if the pump fluid pressure is such as to prevent or resist pumping displacement of a displacer.

In Fig. 9, a closed cycle cooler 1 contains a compressor pump apparatus 2 of the present invention. A heat exchanger 3 provides reduced pressure boiling of a refrigerant by means of reduced pressure applied via line 4 from the suction end of pump 2 whose pressure end delivers via line 5 compressed refrigerant vapour to capillary pressure restrictor 6 which leads liquefied refrigerant to heat exchanger 3.

In Fig. 10, an open cycle cooler and water purifier 1 contains a compressor pump apparatus 2 of the present invention. A heat exchanger 3 provides reduced pressure boiling of a refrigerant (water) by means of reduced pressure applied via line 4 from the suction end of pump 2 whose pressure end delivers via line 5 compressed refrigerant to a condensate collector 6.

z In Fig . 119 (at least) three independent electromagnetic actuation means 51,52., 53 are coupled together in series in a rigid cylindrical casing or housing 54. At opposite end portions of casing 54 are a transverse inlet port 55 and a longitudinal outlet port 56 respectively. Port 56 is in a closed end 57 of casing 54. Port 55 is adjacent an open nd 59 of casing 54, which end is closed by a plug 60 having 0-ring 63. and held in place by clamp ring 62. Around each actuation means 51,52.53 is a respective sleeve portion 63.64 or 65 of a tensible elastic flexible tube 66. The interfacial region of each set of adJavent said actuation means is a node M or N, where ring shaped profiles 67 of tube 66 are seated in corresponding recesses (riot shown specifically) in ends of each actuation means 51,52, 53. The pro.C.Iles 67 form seals in their seatings, by action of compressive force exerted longitudinally by the clamp ring 62, thereby isolating pressure actuation fluid in (,!rich raid actua.tinn means from each other.

Each actuation means 51,52 or 53 contains a displacer piston A capable of longitudinal motion but not intended to be capable of rotational motion, whereby piston A will enable pressure actuation fluid (e.g. a suitable hydraulic liquid) to be discharged from outlet port X into the circumjacent region between the respective actuation means and its corresponding sleeve portion, so that the sleeve portion is expanded to occlude or obturate the pa..-,sageway or space between the exterior of the sleeve portion and the interior face of surrounding casing 54. Each piston A contains a stepped passage C containing a leakage return ball val.ve D, so that any pressure actuation fluid leakiril; from the operative side (right side) of the piston to the dead side (left side) of the piston may return from the dead side to the operative side via passage C and valve D when the piston approaches the end of its return stroke.

l.,'ic[i actuation means 51,52 or 53 has a respective series of electromagnetic coils E, one or more of which which can be energised at apprioriate time(s) to apply force(s) to piston(s) A, so as to move said piston(s) longitudinally as required.

in Fig,. 12, two independent electromagnetic aettintion means 71.,72 are coupled together. Each said actuation menns contains'a respective displacer piston A capable of longitudinal motion and rotation motion, in relation to corresponding sets of electromotor stator coils 73# which can be appropriately energised to enable longitudinal and rotation motions of either or both pistons A as required. Each piston A has a respective male screw thread 74 on its exterior. engaging a corresponding female thread 75 (or vice versa) of the actuation means 71 or 72. The engagement enables the rotational velocity of the periphery of each piston A to be translated into a slower longitudinal velocity of the piston A, so as to enable high end thrusts to be exerted by the operative sides of the pistons. Interface P/Q is a line of isolation between the two actuation means 71972, on either side of which line is a port X or Y through which will. be displaced pressure actuation J1 fluid. When a piston A closes its respective said port, it is not essential to provide any electromagnetic load to that piston, during which time the corresponding tensible elastic flexible sleeve portion (e.g. 63,64 or 65 of Fig. 11) will remain extended. Each piston A contains a leakage return valve -D in a manner similar to that of Fig. 11.

In the modified ptimp apparatus of Fig. 13, a distributer R for pressure actuation fluid is shown instead of control. means 40 of Fig. 2, and instead of the electromagnetic actuation means 51,52,53 of Fig. 11.

1 Pump apparatus, and any components thereof, shown in the accompanying drawings can be modified according to the description given above the first reference to the drawings. In general, the present invention includes equivalents and modifications arising from all the disclosures of the present application.

It will be appreciated that a third aspect of the present invention is a metho d of pumping fluid(s), comprising utilising at least one pump, or pump apparntusq according to the first or second aspect of the invention.

CLA IPIS A pump for pumpable fluid(s), e.g. a pumpable mixture from an oil well or available in the oil industry, comprising:

(a) a container having at least one inlet and at least one outlet; (b) at least one reducible chamber in said container. said chamber being communicatable with said at least one iillet atid said at least one outlet, said chamber having at least one displaceable boundary to contract or expand capacity or said chamber; (c) at least one tensible displacer means for displacing said at least one displaceable chamber boundary so as to contract or expand said chamber, the expansion enabling said chamber to be at least partly charged with displaceable fluid(s) from said at least one i.nlet,, the contraction enabling sald chamber at least partly to discharge displaceable fluid(s) therefrom; (d) at least one first valve means for resisting flow of pumpable fluid(s) into said chamber, the resisting being in a flow path from said at least one inlet; (e) at least one second valve means for resisting flow of pumpable fluid(s) into said chamber, the resisting being in a flow path from said at least one outlet.

2. A pump as claimed in claim 1, comprising at least one control means for controlling displacement(s) of at least one said tensible displacer means (c).

3. A pump as claimed in claim 1 or 2, wherein said container (a) is rigid.

3 5 1 4. A pump as claimed in any one of claims 1 to wherein at least one said displaceable boundary comprises or is constituted by at least one said tensible displacer means (c).

39 1 k 5. A pump as claimed in any one of claims 1 to 4, wherein: a first said tensible displacer means (c) is disposed relative to said at least one inlet; a second said tensible displacer means (c) is disposed relative to said at least one outlet; a third said tensible displacer means (c) is disposed between said first and second tensible displacer means.

6. A pump as claimed in claim 5, wherein chamber (b) is constituted by said container (a).

A pump as claimed in any one of claims 1 to 6, wherein at least one said tensible displacer means (c) comprises at least one tensible elastic envelope.

8. A plimp as claimed in claim 7, wherein at least one said tensible elastic envelope is selected from at, one balloon and at least one balloon portion.

9. A pump as claimed in any one of claims 1 to 8, wherein at least one said tensible displacer means (c) comprises at least one tensible nonelastic envelope.

lc). A pump as claimed in any one of claims 1 to 9, comprising, at least one actuation means for aettiating,,it least one sal.d tensible displacer means (c).

11. A pump as claimed in claim 10, wherein at least one said actuation means is pressure fluid actuation means.

12. A pump as claimed in any one of claims 1 to 119 wherein at least one said actuation means is magnetic actuation means.

13. A pump as claimed in any one of claims 1 to 12, wherein at least one said actuation means is motor actuation means.

Published 1991 at The Patent Office. State House-66/71 High Holborn, LondonWC I R47P. Further coptesmay be obtained from Sales Branch. Unit 6. Nine Mile Point Cwmfelinfach. Cross Keys. Newport. NP1 7RZ. Printed by Multiplex techniques lid, St Mary Cray. Kent.