FLUID DRIVEN DIAPHRAGM PUMP

1 . A diaphragm for a fluid pump, comprising:

a first layer formed from a first material that inhibits or prevents vapor permeation through the diaphragm; and

a second layer coupled to the first layer and formed from a second material different than the first material.

2 . The diaphragm of claim 1 wherein the first material includes at least one of fluoropolymers, perfluoroalkoxy (PFA), polyfluoroethylenepropylene (FEP), polytetrafluoroethylene (PTFE), liquid crystal polymers, nylons, thin metal foil or film, or ethylene vinyl alcohol.

3 . The diaphragm of claim 2 wherein the second material includes at least one of NBR rubber, H-NBR, NBR coated or impregnated fiber or nylon materials, or a fluoroelastomer.

4 . The diaphragm of claim 2 which also comprises a third layer and wherein the first layer is received between the second and third layer.

5 . The diaphragm of claim 4 wherein the third layer is formed from the second material.

6 . The diaphragm of claim 4 wherein the second layer and third layer are both overmolded on the first layer.

7 . The diaphragm of claim 4 wherein the first layer is fully encapsulated between the second and third layer.

8 . The diaphragm of claim 4 wherein the second and third layers each include a first portion adapted to be trapped between opposed bodies and the second and third layers each also include a second portion inboard of the first portion and wherein the first layer is fully encapsulated between the second portions of the second and third layers.

9 . The diaphragm of claim 1 wherein the first layer is continuous and without perforations in an area of the diaphragm adapted to be exposed to a fluid.

10 . The diaphragm of claim 1 wherein the first layer includes a base material and a coating that prevents vapor permeation therethrough.

11 . The diaphragm of claim 2 wherein the fluoropolymer is a fluoroelastomer.

12 . A fluid pump, comprising:

a housing having a vent opening;

a diaphragm carried by the housing and defining with the housing a fluid chamber for receipt of a fluid, wherein the fuel chamber is on one side of the diaphragm and the vent opening is on the other side of the diaphragm such that liquid fuel does not flow through the vent opening; and

a vent chamber communicated with the vent opening and including a vapor filter, the vapor chamber and vapor filter being arranged so that fluid flowing out of the vapor vent flows through the vapor filter.

13 . The fluid pump of claim 12 wherein the vapor filter includes charcoal.

14 . The fluid pump of claim 12 wherein the housing includes multiple vent openings and each vent opening is communicated with one or more than one vapor filter.

15 . The fluid pump of claim 12 wherein the vent chamber is longer than it is wide and wherein the vapor filter is longer than it is wide and the vapor filter fills the width of the vent chamber so that vapor must flow into the vapor filter and cannot flow around the vapor filter.

16 . The fluid pump of claim 15 wherein the vent chamber is more than 3 times as long as it is wide.

17 . The fluid pump of claim 15 wherein the vent chamber has more than one change of direction and is circuitous.

18 . A diaphragm for a fluid pump, comprising:

a planar rim, a center region inboard of the rim and multiple retention features formed in the rim.

19 . The diaphragm of claim 18 wherein the retention features include voids formed through the rim and circumferentially spaced apart about the rim.

20 . (canceled)

21 . (canceled)

22 . (canceled)