When using vector layers in OpenLayers, it is always best to use the filter startegy instead of the filter parameter in the layer:

var filterStrategy = new OpenLayers.Strategy.Filter({filter: your_filter_here});

var station = new OpenLayers.Layer.Vector("station", {
    strategies: [ filterStrategy ]
});

and:

$("#button1").click(function () {
    var filter = new OpenLayers.Filter.Logical({
        type: OpenLayers.Filter.Logical.OR,
        filters: [
        new OpenLayers.Filter.Comparison({
            type: OpenLayers.Filter.Comparison.EQUAL_TO,
            property: "id_station",
            value: 2
        })]
    });
    filterStrategy.setFilter(filter);
});

I've built a working example available here:

http://jsfiddle.net/47kyN/

When using vector layers in OpenLayers, it is always best to use the filter startegy instead of the filter parameter in the layer:

var filterStrategy = new OpenLayers.Strategy.Filter({filter: your_filter_here});

var station = new OpenLayers.Layer.Vector("station", {
    strategies: [ filterStrategy ]
});

and:

$("#button1").click(function () {
    var filter = new OpenLayers.Filter.Logical({
        type: OpenLayers.Filter.Logical.OR,
        filters: [
        new OpenLayers.Filter.Comparison({
            type: OpenLayers.Filter.Comparison.EQUAL_TO,
            property: "id_station",
            value: 2
        })]
    });
    filterStrategy.setFilter(filter);
});

I've built a working example available here:

https://jsfiddle.net/d8f7120x/2/