Abstract: A thermal desalination system adapted to produce distilled water from feed water which may be sea water, based on a forward feed evaporator made up of a main water feed line, a vapor feed line, a distilled water main line and any number of effect groups. The effect groups include any number of effects which in turn include vapor inlets, water inflow lines, concentrate outflow lines that drain into a common concentrate drainage line, a vapor and water outlet in fluid communication with the distilled water main line, and heat transfer means that condense part of an inlet vapor to produce the distilled water.

Abstract: A system and method for separating at least a part of the solids from brine having an initial temperature T1, the system comprising a crystallizer comprising a crystallizer inlet for receiving therein said brine, a crystallizer first outlet for discharging vapor having a first pressure P1, evaporated from at least a part of said brine, and a crystallizer second outlet for discharging a slurry having a final temperature T2 lower than said initial temperature T1; a separator comprising a separator inlet for receiving therein said slurry, a separator first outlet for discharging therefrom said part of the solids separated from said slurry, and a separator second outlet for discharging therefrom a remaining liquid having a temperature substantially equal to T2; a compressor comprising a compressor inlet for receiving therein said vapor, and a compressor outlet for discharging therefrom a compressed vapor having a second pressure P2 higher than said pressure P1; and a condenser comprising a condenser first inlet f

Abstract: A multi-effect evaporator, having an upstream and a downstream end, adapted for distillation of water. It includes a plurality of effects connected in a series manner and arranged into groups. Each group has a common parallel water feed inlet adapted to supply all effects in the group with feed water. The evaporator further includes a main feed water line in fluid communication with the most upstream group. An array of heaters is disposed along the line, adapted for heating the feed water before its entry into the effects of the latter group. Each effect includes means for forwarding the second outlet vapor into one of the heaters for heating the feed water. Each group includes a pump adapted to extract the concentrate from the effects of the group and pump it into the common parallel water feed of an adjacent downstream group.

Abstract: According to one aspect of the present invention, there is provided a desalination system comprising a plurality of elongated pressure vessels (PV). Each PV has a longitudinal axis, oriented such that the longitudinal axis thereof is of a vertical orientation. Each of the PVs is adapted to receive therein a plurality n of desalination membranes. The membranes located above the lowermost membrane within the PV have a total weight allowing them to function as a mechanism limiting axial expansion of the lowermost membrane, whereby the PV is free of any additional limiting mechanism.

Abstract: A multi-effect evaporator, having an upstream and a downstream end, adapted for distillation of water. It comprises a plurality of effects serially connected and arranged into groups. Each group has a common parallel water feed inlet adapted to supply all effects in the group with feed water. The evaporator further includes a main feed water line in fluid communication with the most upstream group. An array of heaters is disposed along the line, adapted for heating the feed water before its entry into the effects of the latter group. Each effect comprises means for forwarding the second outlet vapor into one of the heaters for heating the feed water. Each group comprises a pump adapted to extract the concentrate from the effects of the group and pump it into the common parallel water feed of an adjacent downstream group.

Abstract: Disclosed is a compact heat pump using water as refrigerant, including a casing having a first and second end sections and an intermediate section located therebetween, with an evaporator located at the first end section, configured for containing said water and allowing evaporation of at least a part of the water to produce vapor and remove heat from the remainder of the water. At least one agitator scoop is located within said evaporator, with one or more demisters installed between the evaporator and the compressor. The one or more compressors induce evaporation by maintaining vacuum at least at an intake conduit, and are configured for receiving the vapor through the intake conduit after passing through a heated demister. The condenser is configured for receiving the compressed vapor from the compressor, lowering the vapor temperature and condensing it back into a liquid state.

Abstract: A piston for a linear spool valve, the valve comprising a body having a inner surface. The body is made of a material with a relatively low heat expansion coefficient ?1. The piston comprises a contact member having an outer surface and being adapted to reciprocate within the body of the valve so that the outer surface is in contact with the inner surface. The contact member has at least a first layer made of a material with a heat expansion coefficient ?2 essentially greater than ?1, i.e. ?2>>?1, and at least a second layer made of a material with a heat expansion coefficient ?3 close to ?1. This causes the contact member to be adapted to behave, along said outer surface, as a material having a heat expansion coefficient essentially closer to ?1 than to ?2. One of the layers constitutes an outer layer of the contact member and comprises the outer surface.

Abstract: A method of cleaning a fouled RO membrane in a module for RO separation, the membrane having feed side and permeate side, the foulant accumulating at the feed side. The cleaning method comprises: feeding concentrated saline solution to the feed side of the RO membrane under the high gauge pressure of the normal RO separation process; feeding dilute saline solution to the permeate side of the RO membrane under higher pressure than the permeate pressure of the normal RO process, so that a net driving differential ?PN is directed to the feed side, whereby the solvent is being sucked from the permeate side to the feed side, penetrates into the interface between the membrane and the accumulated foulant, and separates the foulant from the membrane surface; and withdrawing the concentrated saline solution together with the separated foulant and the penetrated solvent from the feed side of the RO membrane.

Abstract: A three-way two-position poppet valve (10) comprising a housing (12) with a generally cylindrical valve chamber (14), a first (20) and a second (16) port with coaxial 1 valve seats (26, 28) at the ends of the chamber, and a third lateral working port (18). A poppet body (36) is disposed reciprocably in the valve chamber so that in a first position of the poppet body the first valve seat (26) is sealed and the second port communicates with the working port, and in a second position the second valve seat (28) is sealed and the first port communicates with the working port. The valve is characterized in that the housing has two coaxial cylindrical passages (24, 30) adjacent the respective valve seats, while the poppet body has two coaxial cylinder parts (44, 48) slidingly and sealingly fitting the cylindrical passages, so that the poppet body is always supported in at least one of the cylindrical passages and fluid communication between the first and the second port is always prevented.

Abstract: A method of boron removal from saline water containing boron and magnesium or calcium salts including a multi-stage reverse-osmosis (RO) separation process and comprising the steps of a first stage RO separation at pH<8.2; a second stage RO separation over at least part of the first-stage permeate; a third stage RO separation over the second-stage brine. The method is characterized in that the second stage separation is carried at pH>9 and the brine concentration is limited to a degree preventing Mg(OH)2 or CaCO3 scaling on RO membrane surfaces, the permeate constitutes product water, and the brine contains boron and magnesium or calcium ions; the third stage separation is carried at weak-acid pH, whereby the bulk of the magnesium or calcium ions are separated with the brine, while the bulk of the boron ions are retained in the permeate.

Abstract: A gasdynamic arrangement for a multi-stage centrifugal turbomachine, such as a two-stage compressor, comprising two coaxial impellers assembled on a common shaft with axial intake ports and radial peripheral discharge zones, the intake ports of the two impellers preferably pointing away from each other; a cylindrical vessel concentrically housing the impellers and the intake duct; a partition wall between the two impellers having a first and a second group of apertures; a first array of curved ducts conveying the flow from the first impeller discharge zone to the first group of apertures in the partition wall, the flow further passing through a chamber in the vessel to the intake port of the second impeller, and a second array of curved ducts conveying the flow from the second impeller discharge zone to the second group of apertures in the partition wall, the flow further going to the discharge port, the two flows bypassing each other in opposing directions at the partition wall.

Abstract: A method is provided for improving the performance of a heat-pump installation for making ice operating on the principle of mechanical water vapor compression. The installation comprises an evaporator-freezer chamber communicating with a compressor chamber having a centrifugal compressor unit. The method comprises a) providing a first droplet separator of the louver type between the evaporator-freezer chamber and the compressor chamber, for primary separation of the coarser droplets; b) providing a second droplet separator of the knitmesh type downstream of the first droplet separator, for secondary separation of the remaining fine spray, and c) providing a continuous or intermittent spray of a dilute solution of a highly water-soluble inorganic salt in counter-current to the vapor flow from a plurality of spray nozzles located between the first and the second droplet separators and facing the first droplet separator.

Abstract: A lightweight, heavy duty, large volume centrifugal compressor for use in mechanical vapor compression systems, especially water vapor compression systems in heat pump installations, said compressor comprising a shaft driven propeller-like rotary member consisting of a frusto-conical hub and a plurality of curved blades made of a lightweight material, each being secured to said hub along a longitudinal curved line and radially extending therefrom; each pair of adjacent blades being interconnected by a bridging membrane member of a lightweight material curvingly extending from the roots of the leading edges of said adjacent blades to the tips of the rear edges of the blades; said rotary member being encompassed within a closely fitting shroud, so that curved vapor flow channels are defined between each said pair of blades, their associated membrane member, and the shroud.