Diaphragm structure for electrolytic cells for the electrolysis of aqueous salt solutions

Claim 2

A diaphragm for electrolytic cells for the electrolysis of aqueous salt solutions which comprises an electrochemically active porous portion comprised of asbestos fibers attached to an electrochemically inactive substantially fluid impervious portion, said electrochemically inactive substantially fluid impervious portion being comprised of a fabric layer attached to a fluid impervious film layer.

Claim 3

The diaphragm of claim 1 in which said fluid impervious film layer is comprised of a fluorinated olefin selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene-propylene (FEP), polychlorotrifluoroethylene, polyvinylfluoride, and polyvinylidene fluoride.

Claim 4

The diaphragm of claim 2 in which said porous portion is comprised of asbestos fibers deposited on a porous fabric.

Claim 5

The diaphragm of claim 3 in which said porous fabric is a napped fabric.

Claim 6

The diaphragm of claim 3 in which said porous fabric is a scrim fabric.

Claim 7

The diaphragm of claim 4 or claim 5 in which said impervious layer is comprised of two fabric layers bonded to an intermediate fluid impervious film layer.

Claim 8

The diaphragm of claim 3 or claim 6 in which said fluid impervious fluid layer is comprised of fluorinated ethylene-propylene (FEP).

Claim 9

The diaphragm of claim 7 in which said fabric layer of said substantially fluid impervious portion is selected from the group consisting of a felt fabric and a napped fabric.

Claim 10

The diaphragm of claim 1 in which said fabric layer attached to said fluid impervious film layer is comprised of thermoplastic materials selected from the group consisting of polyolefins, polyarylene sulfides, and mixtures thereof.

Claim 11

The diaphragm of claim 9 in which said polyolefin is selected from the group consisting of olefins having from 2 to about 6 carbon atoms and their chloro- and fluoro-derivatives.

Claim 12

The diaphragm of claim 9 in which said polyarylene sulfide is polyphenylene sulfide or polynaphthylene sulfide.

Claim 13

The diaphragm of claim 3 in which said porous fabric is comprised of a polyolefin selected from the group consisting of olefins having from 2 to about 6 carbon atoms and their chloro- and fluoro-derivatives.

Claim 14

The diaphragm of claim 12 in which said porous fabric is polytetrafluoroethylene.

Claim 15

In an electrolytic cell for the electrolysis of aqueous salt solutions which comprises a cell body; an anode compartment containing at least one anode; a cathode compartment containing at least two cathodes, said anode being inserted between and spaced apart from said cathodes; a diaphragm separating said anode compartment from said cathode compartment; inlets for introducing fluids into said anode compartment and said cathode compartment; outlets for removing fluids from said anode compartment and said cathode compartment; means for introducing electric current and removing electric current from said cell body, the improvement which comprises: said diaphragm being comprised of an electrochemically active porous portion comprised of asbestos fibers attached to an electrochemically inactive substantially fluid impervious portion, said electrochemically inactive substantially fluid impervious portion being comprised of a fabric layer attached to a fluid impervious film layer.

Claim 16

In an electrolytic cell for the electrolysis of aqueous salt solutions which comprises a cell body; an anode compartment containing at least one anode; a cathode compartment containing at least two cathodes, said anode being inserted between and spaced apart from said cathodes; a diaphragm separating said anode compartment from said cathode compartment; inlets for introducing fluids into said anode compartment and said cathode compartment; outlets for removing fluids from said anode compartment and said cathode compartment; means for introducing electric current and removing electric current from said cell body, the improvement which comprises: said diaphragm being comprised of an electrochemically active porous portion comprised of asbestos fibers attached to an electrochemically inactive substantially fluid impervious portion, said electrochemically inactive substantially fluid impervious portion being comprised of a fabric layer attached to a fluid impervious film layer.

Claim 17

The electrolytic cell of claim 14 in which said fluid impervious film layer is comprised of a fluorinated olefin selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene-propylene (FEP), polychlorotrifluoroethylene, polyvinylfluoride, and polyvinylidene fluoride.

Claim 18

The electrolytic cell of claim 15 in which said porous portion is comprised of asbestos fibers deposited on a porous fabric, said porous fabric being in contact with said cathodes.