Document ppeBR6NKJEgVRDa4kn6qEp7dw

American Society of Heating and Ventilating Engineers Guide, 1934 Two types of condensation meters are in general use: the tilting bucket meter and the revolving drum or rotor meter of which there are several makes on the market. Condensation meters should not be operated under pressure. They are made for either gravity or vacuum installation. Continuous flow traps and vented receivers ahead of gravity type meters are desirable. A typical Chapter 36--District Heating as the area of the orifice. The vertical lift of the plug, which is proportional to the flow, is transmitted by means of a lever to an indicator and to a pencil arm which records the flow on a strip chart. The total flow over a given period is obtained by measuring the area by using a planimeter on the chart and applying the meter constant. Flow meters using an orifice, Venturi tube, flow nozzle, or Pitot tube as the primary device are made by a number of manufacturers and can be obtained in either the mechanical or electrically operated type. The electric flow meter makes it possible to locate the instruments at some Fig. 5. Typical Gravity Installation of Condensation Meter Fig. 6. Gravity Installation for Condensation Meter Using Vented Receivers . gravity installation for a condensation meter is shown in Fig. 5, while Fig. 6 is a gravity installation using a vented receiver ahead of the meter. Fig. 7 shows a vacuum installation without a master trap. The pipe discharge from the meter should be of ample size pitched so as to rapidly remove the condensate from the meter. It is advisable to follow the instructions of the meter manufacturer in installing a meter as the successful operation of any meter depends upon its being properly connected. Steam flow meters are available in many types and combinations, as indicated in the subdivision covering fluid meters on page 528. The orifice and plug meter is one in which the steam flow varies directly 530 Fig. 7. Vacuum Condensation Meter Installation without Master Trap distance from the primary element, which is not always possible with the mechanical flow meter. Flow meters employing the orifice, Venturi tube, flow nozzle or Pitot, tube should be so selected as to keep the lower operating range of the load above 20 per cent of the capacity of the meter. This is desirable for accuracy as the differential pressure at light loads is too small to properly actuate the meter. A few general points to be considered in installing a meter of this type are as follows: 1. It is desirable to place the differential medium in a horizontal pipe in preference to a vertical one, where either location is available. 2. Reservoirs should always be on the same level and installed in accordance with the instructions of the meter company. 3. The meter body should be placed at a lower level than that of the pressure differ ential medium. Special instructions are furnished where-the meter body is above. 4. Meter piping should.be kept free from leaks. 5. Sludge should not be permitted to collect in the meter body. 531 - /