In order to make search on range of numerical option values, I've implemented this version. As spree stocks option value in a string, I've to cast it to compare. In the original version of this gist, I was unable to make or join between the created scope. With arel table, no problem.

product_filters.rb

    def ProductFilters.ov_range_test(range1, range2)
      ov = Arel::Table.new("spree_option_values")
      cast = Arel::Nodes::NamedFunction.new "CAST", [ ov[:presentation].as("integer")]
      comparaisons = cast.in(range1..range2)
      comparaisons
    end

    Spree::Product.add_search_scope :screenSize_range_any do |*opts|
      conds = opts.map {|o| Spree::ProductFilters.screenSize_filter[:conds][o]}.reject {|c| c.nil?}
      scope = conds.shift
      conds.each do |new_scope|
        scope = scope.or(new_scope)
      end
      option_values=Spree::OptionValue.where(scope).joins(:option_type).where(OptionType.table_name => {:name => "tailleEcran"}).pluck("#{OptionValue.table_name}.id")
      Spree::Product.where("#{Product.table_name}.id in (select product_id from #{Variant.table_name} v left join spree_option_values_variants ov on ov.variant_id = v.id where ov.option_value_id in (?))", option_values)
    end

    def ProductFilters.screenSize_filter
      conds = [ [ "20p ou moins",ov_range_test(0,20)],
      [ "20p - 30p",ov_range_test(20,30)],
      [ "30p - 40p" ,ov_range_test(30,40)],
      [ "40p ou plus",ov_range_test(40,190)]]
      { :name   => "taille",
        :scope  => :screenSize_range_any,
        :options => :tailleEcran,
        :conds  => Hash[*conds.flatten],
        :labels => conds.map {|k,v| [k,k]}
      }
    end