highstock

HTML

<script src="http://github.highcharts.com/bugfix/highstock.js"></script>
<div id="container" style="height: 300px"></div>

JavaScript

$(function() {
  (function(H) {
    H.wrap(H.Series.prototype, 'gappedPath', function(proceed) {
      var gapSize = this.options.gapSize,
        xAxis = this.xAxis,
        points = this.points.slice(),
        i = points.length - 1;

      if (gapSize && i > 0) { // #5008

        // extension for ordinal breaks
        while (i--) {
          if (points[i + 1].x - points[i].x > gapSize) {
            points.splice( // insert after this one
              i + 1,
              0, {
                isNull: true
              }
            );
          }
        }
      }
      return this.getGraphPath(points);

    })
  }(Highcharts))

  var data = function() {
      var array = [];
      for (var i = 0; i < 1000; i++) {
        if (i % 25 === 0) {
          array.push([90000000 + 3600 * 1000 * i + 3600 * 500, 3 * Math.random()]);
        } else {
          array.push([90000000 + 3600 * 1000 * i, 3 * Math.random()]);
        }
      }
      return array;
    },
    data1 = data(),
    data2 = data();
  $('#container').highcharts('StockChart', {
    xAxis: {
      ordinal: false
    },
    yAxis: [{
      height: '50%',
      lineWidth: 2
    }, {
      top: '50%',
      height: '50%',
      offset: 0,
      lineWidth: 2
    }],
    plotOptions: {
      line: {
        gapSize: 3600 * 1000,
        dataGrouping: {
          enabled: false
        }
      }
    },
    series: [{
      data: data1
    }, {
      yAxis: 1,
      data: data2
    }]
  });
});