Abstract: A swimming pool water filtration unit includes: a plurality of shallow-bed sand filter modules that receive water from a swimming pool and discharge filtered water simultaneously via a pool water return conduit common to all modules. A valve arrangement associated with the filter modules: (i) selectively but simultaneously switching on and off of all filtered water flow from the trays, which takes place through the return conduit common to all trays, to the pool water return coupling of the tank; and (ii) enable backwash water flow into the individual filter trays in selectable order, preferably through the common return conduit, and opens a conduit for backwash water to pass to waste in a switching state where water flow to the pool water return coupling is blocked.

Abstract: A double-skinned inflatable bottle blank is manufactured by: (i) stacking two sheets of liquid impermeable, flexible foil material; (ii) blanking the sheets; (iii) bonding the two blanks along joining seams that follow contoured perimeter edges to define a double skinned blank which can be inflated through an inflation location; (iv) additionally bonding the two blanks at in a predetermined grid of seams to provide an upstanding peripheral wall with intersecting, inflatable stiffener structures; (v) folding the double skinned blank; and (vi) selectively bonding together portions of the joined perimeter edge of the double skinned blank to define a double-skinned, inflatable bottle blank with an internal cavity surrounded by a bottom wall, peripheral wall and top wall with a dispensing orifice, the inflatable stiffener structures between the seams providing an exoskeleton about the internal cavity when inflated.

Abstract: In a secure communication system, a first communication device includes a first list of numbers and a first number selector for periodically selecting a different number in the first list. The first communication device further includes a first encryption key generator for generating a first encryption key based on the selected number for generating an encrypted message. A second communication device includes a receiver for receiving the encrypted message, a second list of numbers identical to the first list of numbers, and a second number selector synchronized with the first number selector so as to select the same number as the first number selector, and a second encryption key generator for generating a second encryption key identical to the first encryption key. The second communication device decrypts the encrypted message using the second encryption key. An associated method for providing secure communication of a message between parties is also provided.

Abstract: The present invention concerns a double-skinned inflatable bottle blank and its method of manufacturing which comprises: (i) stacking two sheets of liquid impermeable, flexible foil material, preferably in coplanar arrangement; (ii) blanking the sheets to create respective, preferably shape-congruent blanks having each a contoured perimeter edge; (iii) bonding the two blanks along joining seams that follow the contoured perimeter edges, but for at one or more inflation locations, thereby to define a double skinned blank into which an inflating fluid can be introduced through the inflation location; (iv) additionally bonding the two blanks at a plurality of discrete stiffening seams which are arranged in a predetermined grid or pattern thereby defining a grid-work of intersecting, inflatable stiffener structures in at least such part of the double skinned blank which will provide an upstanding peripheral wall of the bottle when erected through inflation; (v) folding the double skinned blank; and (vi) selective

Abstract: A system for providing secure communication of a message between parties is provided. The system includes first and second communication devices. The first communication device includes a first list of numbers and a first number selector for periodically selecting a different number in the first list. The first communication device further includes a first encryption key generator for generating a first encryption key at a certain time. The first encryption key generator uses the number selected by the first number selector at a certain time to generate the first encryption key from the first list of numbers. The first communication device also includes an encryptor, for encrypting a message using the first encryption key, and a transmitter for transmitting the encrypted message. The second communication device includes a receiver for receiving the encrypted message and a second list of numbers, the second list of numbers being identical to the first list of numbers.