Reverse osmosis watermaker with pressure booster

Description

[0001] This invention deals with a reverse osmosis desalinator of the type comprising the features mentioned in the preamble of the principal claim.

[0002] A desalinator comprising such features is known from FR2732727. Another known desalinator is described in US6491813.

[0003] This desalinator uses a pressure amplifier of the double cylinder and double piston type to transform a medium-pressure water flow generated by a pump into a high-pressure flow suitable to supply the reverse osmosis membranes of a desalinator. Other types of pressure amplifiers or recuperators are also usable for this purpose. Typically, they are so-called Clark pump amplifiers. These desalinators are used on board recreational watercraft where the availability of electricity to power the desalinator is quite limited, given they are generally low voltage and direct current systems.

[0004] Use on board small and medium-size watercraft however poses numerous problems of a technical nature for which known desalinators have not provided an effective answer. A first problem deals with minimization of space requirements. As a matter of fact, the dimensions of known desalinators are not always compatible with space availability on board. In any case, the reduction of such space requirements remains an extremely important objective both for the watercraft manufacturers and for the boaters who reluctantly give up storage space that could otherwise be used on board. Moreover, there is the problem of the cost and of the sensitivity of the high and medium pressure fittings and tubes which, beyond constituting a source of potential damage, represent a cost also in the manufacturing and assembly stage of the desalinator.

[0005] A further problem addressed and solved by this invention is producing a desalinator in which the coupling between the heads, pressure amplifier and vessels that contain the reverse osmosis membranes is particularly simple but effective, easy to assemble and disassemble and at the same time highly reliable, notwithstanding the considerable pressures in play.

[0006] The base problem of this invention is providing a desalinator that is particularly designed for use in recreational watercraft which, beyond guaranteeing low consumption and contained costs, can be made with reduced space requirements and in such a way that installation is simple in minimal and not otherwise easy to use spaces.

[0007] Within the scope of this problem, an important task of the invention is to simplify assembly of the desalinator and reduce manufacturing costs thereof. At the same time, the desalinator according to the invention has less visible fittings and tubes and is therefore more solid and less subject to damage.

[0008] This problem is solved and these advantages are achieved with a reverse osmosis desalinator according to claim 1.

[0009] The reverse osmosis desalinator comprises: a pressure amplifier of the double cylinder and piston type, a respective closure head for each cylinder, at least one reverse osmosis group with pressurization container closed at the opposite axial ends by respective heads, as well as valve systems and flow conduits which are connected to the heads in order to control the pressurized water flow from and towards the pressure amplifier and the flow of product and discharge from and towards the reverse osmosis group, in which at least some of the flow conduits, and / or the seats of the valve systems, are integrated in the heads.

[0010] Preferably, both cylinders of the pressure amplifier are inserted creating a seal in a respective seat of the respective head and the high-pressure container of the at least one osmosis group having opposite longitudinal ends housed creating a seal in respective seats which are formed in the heads.

[0011] According to the invention, the heads are interconnected to each other and held in place by insertion onto the cylinders and the container by rods extended between the opposite heads.

[0012] The presence of the rods and their placement between the heads permit balancing of the load exerted by the water under pressure in the high-pressure containers and in the cylinders of the pressure amplifier.

[0013] Preferably, the flow conduits which are integrated in the heads at least partially comprise the exchange conduits between the pressure amplifier and the reverse osmosis group, or rather all or almost all of the conduits that require high-pressure-resistant (in the order of 50-80 bar) fittings and tubes, as well as all, or almost all, the conduits that require medium-pressure-resistant (in the order of 7-10 bar) fittings and tubes. Such conduits and fittings are made as a single piece through appropriate machining of the heads which close both the cylinders of the pressure amplifier and the containers (cylinders) that pressurize the membranes.

[0014] It is possible to make desalinators with these heads which integrate the flow conduits, both with one membrane as well as multiple membranes, with minimal use of external fittings or tubes, as these components are integrated in the heads through machining of the same.

[0015] The aforementioned heads also comprise the seats of the non-return valves, if there are any, hydraulically connected to the cylinders of the pressure amplifier. Although it is possible to form these valves in the central part of the pressure amplifier, where the main switching valve of the amplifier is integrated, the positioning of these seats in the same bodies that form the heads offers the advantage of greater accessibility of these valves and easy machining of the same.

[0016] The features and advantages of the invention will be more clearly shown in the detailed description of an illustrated preferred embodiment, given solely by way of example, with reference to the appended drawings in which: FIGS. 1 and 2 are respectively transparent and solid perspective views of a desalinator made according to this invention; FIGS. 3 through 6 are elevation and perspective views of a head of the desalinator of the preceding figures; FIGS. 7 through 10 are elevation and perspective views of another, opposite head of the desalinator of the preceding figures; FIG. 11 is a perspective exploded view of the desalinator of FIG. 1; FIG. 12 is an enlarged detail of the same desalinator; FIG. 13 is a perspective view of a desalinator according to the invention with double reverse osmosis group.

[0017] In the figures, 1 indicates as a whole a reverse osmosis desalinator according to this invention.

[0018] The desalinator 1 comprises an opposing-piston-type pressure amplifier 2, with a double cylinder 3,4 and respective double piston 5,6 attached at the respective axial end of a shaft 7. The shaft 7 has multiple sets of longitudinal incisions 8 arranged like a crown at the periphery of the shaft itself to form four crowns axially spaced at pitch. The two cylinders are coaxial and engaged to protrude from parts that are axially opposite of a central valve body 9 on which is mounted an exchanger valve system 10 with a moveable cassette 11. The functioning and the structural components of the pressure amplifier 2 are the same ones described in patent US6491813 to which reference is made for eventual in-depth analysis and details. It is pointed out that both cylinders 3,4 are inserted creating a seal in a respective seat 12 of the central body 9 and in a respective seat 13, 14 of a respective head 15, 16 which are axially opposite. On the exchanger 10, a collector 18 is highlighted for the discharge of the post-treatment waste that, in the case of marine applications, is made up of a saline solution which is more concentrated than the inflow of sea water.

[0019] The desalinator 1 comprises, moreover, one or more reverse osmosis groups 20, each one comprising a high-pressure container or vessel 21, closed at the opposite axial ends by the respective heads 15, 16. The containers 21 are effectively high-pressure-resistant pipes, made of metal or preferably of a composite structure, of which the opposite longitudinal ends are housed creating a seal in respective seats 22, 23 which are formed in the heads 15, 16.

[0020] A membrane 24, which is wrapped in the form of a cylinder-shaped cartridge, is placed inside each container, with respective opposite inflow and outflow terminals 25 housed in respective seal-creating connectors 27 in the seats of the respective heads 15,16.

[0021] The desalinator 1 comprises, lastly, valve systems and flow conduits connected to the heads in order to control the pressurized water flow from and towards the pressure amplifier as well as the flow of filtered and discharge product from and towards the reverse osmosis group.

[0022] The heads 15, 16 each comprise a respective prismatic block (or of any other preferred shape) preferably made of plastics material or of other corrosion-resistant materials. The two heads 15, 16 are connected to each other by means of rods 17.

[0023] The first head 15 comprises a collector 18 with related hose connector for the supply of the water to be treated. When the desalinator is operating, saltwater at medium pressure (7-10 bar), coming from a low / medium pressure pump that is not represented, is supplied to the collector 18.

[0024] The collector 18 is open in a first seat 30 for a first unidirectional valve 31, which is formed in the thickness of the head 15. The valve 31 is suitable to allow the flow from the collector 18 towards the piston 5, passing through a first hole 32a of plate 32 that has a second hole 33 and that works as end-point closure of the cylinder 3, being located near the end of the same which is housed in the seat 13 of the head 15.

[0025] A second unidirectional valve 34 is housed in a second seat 35 which is also formed in the thickness of the head 15. The valve 34 communicates with the second hole 33 of the plate 32, is structurally identical to the first valve 31 but is oriented in the opposite direction to allow only the outflow from the chamber defined between the head 15 and the piston 3, but not vice versa. The unidirectional valves 31, 34 both comprise a sealing seat 35, a cage 36 and a closure member 37 held between the cage 36 and the seat 35, free to move from and towards the seat 35 on the basis of the direction of the flow that passes through it. When the closure member 37 is in contact with the seat 35, the valve is closed and vice versa it is otherwise open.

[0026] A first conduit 40 is formed in the head 15 and connects the collector 18, a seat for a pressure gage 41, a first transfer seat 42 between the heads 15,16 and an opening 43 for a transfer tube 44 between the collector 18 and the central body 9.

[0027] A second conduit 50 is formed in the head 15 parallel to the conduit 40 and links the seat 35 of the second unidirectional valve, a second transfer seat 52 and a series of adductor holes 51 leading into the chamber 53 which is formed between the connector 27 which protrudes in the seat 22 of the head 15 and the wall of the seat 22 itself. Water under pressure, which is intended for the filtration through the reverse osmosis membrane 22, is introduced in this chamber 53 through the holes 51. The filtered product is expelled from the desalinator via a delivery conduit 54, opened in the centre of the connector 27 and able to communicate in a sealed manner with a central cavity of the membrane 22.

[0028] The second conduit 50 is plugged and sealed by a plug 55.

[0029] On the opposite side, the head 16 respectively comprises, in addition to the seats 14, 23 for the cylinder 4 and for the opposite end of the container under pressure 21, two conduits 61, 62 which connect a third and respectively fourth seat 63, 64 for a respective third and fourth unidirectional valve 65, 66 with a respective third and fourth transfer seat 67, 68.

[0030] The first and third transfer seats, 42 and 67, and the second and fourth transfer seats 52 and 68 are respectively connected to one another by tubular transfer conduits 71,72 which engage creating a seal in the aforementioned seats and extend between the two heads. The unidirectional valves 65, 66 are respectively oriented to allow the flow from and towards the chamber defined between the piston 6 and a second plate 73 which is identical in shape and has the identical function of the plate 32 and also has the identical holes. All the aforementioned unidirectional valves are identical in shape and function.

[0031] A second transfer tube 80 is lastly connected between a chamber 81 defined between the connector 27 protruding in the seat 23 of the head 16 and the wall of the seat itself and the exchanger valve system 10 with a moveable cassette to feed water under pressure, intended for the functioning of the amplifier 2, to the latter.

[0032] In the event in which multiple reverse osmosis groups are used (FIG. 13), they will preferably be connected in series as regards the flow of water to be treated and in parallel as regards the flow of the filtered product. Here too, the connection conduits are integrated in the heads according to the logic indicated above.

[0033] It will be appreciated that by integrating all (or almost all) the flow conduits and the seats of the valve systems both of the pressure amplifier and of the reverse osmosis groups in the heads and using, therefore, only two heads for a desalinator, a substantial reduction of the total space required for the desalinator is obtained, in practice limited only by the external diameter of the pressurization container and by the length of the same. The desalinator may also be arranged in any position whatsoever inside storage lockers, including narrow ones, whether horizontally or up against sides, walls, partitions or the like.

Claims

1. A reverse osmosis desalinator comprising: - a pressure amplifier (2) of the double cylinder (3, 4) and piston (5, 6) type, - a respective closure head (15, 16) for each cylinder, - at least one reverse osmosis group (20) with a high-pressure container (21) which is closed at the opposite axial ends by respective heads (15, 16), said heads (15, 16) comprising a first head (15) and a second head (16), - and valve systems (30-37) and flow conduits (51-55) which are connected to the heads (15,16) in order to control the pressurized water flow from and towards the pressure amplifier (2) and the flow of product and discharge from and towards the reverse osmosis group (20), - in which at least part of the flow conduits and / or of the seats of the valve systems (30-37 and 51-55) are integrated in the heads (15,16), and - both cylinders (3, 4) of the pressure amplifier are inserted creating a seal in a respective seat (13, 14) of the respective head (15, 16), and - the high-pressure container of the at least one osmosis group having opposite longitudinal ends housed and sealed in the respective seats (22, 23) which are formed in the heads (15, 16), characterized by the heads (15, 16) being interconnected to each other and engaged onto the cylinders (3,4) and the container (21) by rods (17) extended between the opposite heads and in that the first head (15) comprises a collector (18) with related hose connector for the supply of the water to be treated, the collector (18) being open in a first seat (30) for a first unidirectional valve (31), which is formed in a thickness of the first head (15), said first unidirectional valve (31) being suitable to allow the flow from the collector (18) towards the piston (5), passing through a first hole (32a) of a plate (32) that has a second hole (33) and that works as end-point closure of the cylinder (3), being located near an end of the same which is housed in the seat (13) of the first head (15), a second unidirectional valve (34) being housed in a second seat (35) which is also formed in the thickness of the first head (15), wherein the second unidirectional valve (34) communicates with the second hole (33) of the plate (32) and is structurally identical to the first valve (31) but is oriented in the opposite direction to allow only the outflow from the chamber defined between the head (15) and the piston (5), but not vice versa, wherein a first conduit (40) is formed in the head (15) and connects the collector (18), a seat for a pressure gage (41), a first transfer seat (42) between the heads (15, 16) and an opening (43) for a transfer tube (44) between the collector (18) and the central body (9), wherein a second conduit (50) is formed in the head (15) parallel to the conduit (40) and links the seat (35) of the second unidirectional valve (34), a second transfer seat (52) and a series of adductor holes (51) leading into a chamber (53) which is formed between the connector (27) which protrudes in the seat (22) of the head (15) and a wall of the seat (22) itself, wherein water under pressure, which is intended for the filtration through a reverse osmosis membrane, is introduced in this chamber (53) through the holes (51), wherein filtered product is expelled from the desalinator via a delivery conduit (54), opened in a centre of the connector (27) and able to communicate in a sealed manner with a central cavity of the membrane, and in that the second head (16) respectively comprises two conduits (61, 62) which connect a third and respectively fourth seat (63, 64) for a respective third and fourth unidirectional valve (65, 66) with a respective third and fourth transfer seat (67, 68), the first and third transfer seats (42, 67), and the second and fourth transfer seats (52, 68) are respectively connected to one another by tubular transfer conduits (71, 72) which engage creating a seal in the aforementioned seats and extend between the two heads (15, 16), the third and fourth unidirectional valves (65, 66) being respectively oriented to allow a flow from and towards a chamber defined between the piston (6) and a second plate (73) which is identical in shape and has identical function of said plate (32) of the first head (15) and also has the identical holes, wherein all the aforementioned unidirectional valves are identical in shape and function.

2. A desalinator according to claim 1, wherein the flow conduits which are integrated in the heads (15, 16) at least partially comprise the exchange conduits between the pressure amplifier (2) and the reverse osmosis group (20).

3. A desalinator according to claim 1 or 2, comprising a plurality of reverse osmosis groups (20) which are interconnected via respective flow conduits which are formed in the heads (15, 16).

4. A desalinator according to claim 3, wherein the reverse osmosis groups (20) are connected to each other in series.

5. A desalinator according to one or more of the preceding claims, wherein the seats of the valve systems integrated in the heads comprise the seats (30, 35) of the non-return valves (31, 34) which are applied to the ends directed towards the heads (15, 16) of the cylinders (3, 4) of the pressure amplifier (2).

6. A desalinator according to claim 5, wherein the non-return valves comprise a closure member (37) which floats in a cage (36) which is connected to a valve seat.

7. A desalinator according to any one of the preceding claims, wherein the tubular transfer conduits (71, 72) are held in their respective seats through the rod coupling between the two heads.

8. A desalinator according to one or more of the preceding claims, wherein the heads comprise respective prismatic blocks wherein are formed both the seats for the cylinders as well as the seats for the pressure containers of the reverse osmosis groups, wherein in the seats of the container are formed respective seal-creating connectors (27) for the membrane of the reverse osmosis groups.

9. A desalinator according to claim 8, wherein the flow conduits and / or the seats of the valve systems integrated in the heads are formed by piercing of the heads.

10. A desalinator according to one or more of the preceding claims in which said rods (17) are placed between said heads (15, 16) such as to equilibrate the load applied by the pressurized water in the cylinders (3, 4) of the pressure amplifier and in the high pressure container (21).