Pressure manometers

Manometer pressure The pressure recorded on a manometer, measured in Pa or mm water gauge. 

Gas-dichte, /. gas(eous) density, -dichtigkeit, /. impermeability to gas. -druck, m. gas pressure, gaseous pressure, -dnickmesser, m. manometer, pressure gage (MU.) accelerometer. -durchlassigkeit, /. permeability for gas. 

Pressure gauges should always be fitted on the discharge side of liquid pumps, to check performance and give warning of a possible drop in flow resulting from dirty strainers. Manometer pressure gauges are required across air filters (see Chapter 2 7). 

Fig. 4-2. Pressure measurement. A. Barometer pressure — 755 mm. B. Closed-end manometer pressure = 105 mm. C. Open-end manometer pressure = 755 — 650 - 105 mm.

Pressure in the volumetric apparatus was measured by a McLeod gage and by a wide-bore (30-mm.) mercury manometer. Pressures measured with the McLeod gage were corrected for capillary depression of the mercury meniscus. Pressure in the gravimetric apparatus was controlled by regulation of the tempera-... 

The most straightforward method for vapor-pressure measurement is the static method, in which the pressure of the vapor above a pure liquid is measured directly with a manometer, pressure gauge, or pressure transducer. All parts of the apparatus must be maintained at a temperature at least as high as that of the sample in order to avoid condensation. Static techniques may be used at high temperatures and pressures with appropriate apparatus construction, but they become difficult at low vapor pressures due to the difficulty of pressure measurement and the effects of impurities. With good equipment and procedures, the accuracy of static vapor pressure measurements can be on the order of 0.1%. 

Conversion factors for mercury manometer pressure units are calculated using die standard value for the acceleration of gravity and die density of mercury at die stated temperature. Additional digits are not justified because the definitions of the units do not take into account die compressibility of mercury or the change in density caused by the revised practical temperature scale, ITS-90. Similar comments also apply to water manometer pressure units. Conversion factors for conventional mercury and water manometer pressure units are based on ISO 31-3. 

Measuring and control equipment medical and other thermometers, blood pressure gauges, manometers, pressure valves, gyroscopes... 

Provide manometer/pressure gauge for gas pressure measurement. 

Air blower and compressor (positive displacement type) are preferable with silencer-cum-filter, dampers for primary (atomising) air, primary and secondary air piping, manometer, pressure regulators for air supply at burner inlet. The positive displacement-type combustion air blowers shall also be able to atomise the oil or separate compressors for atomisation of oil shall be provided. 

All ventilation systems should have a device that readily permits the user to monitor whether the total system and its essential components are functioning properly. Manometer, pressure gauges, and other devices that measure the static pressure in the air ducts are sometimes used to reduce the need to manually measure airflow. "Telltales" and other similar simple devices can also serve as indicators of airflow. The need for and the type of monitoring device should be determined on a case-by-case basis. If the substance of interest has excellent warning properties and the consequence of overexposure is minimal, the system will need less stringent control than if the substance is highly toxic or has poor warning properties. 

Monitoring Pressure Within the Endosure After the initial air flow patterns have been checked, the static pressure must be monitored within the enclosure. Monitoring may be made using manometers, pressure gauges, or combinations of these devices. It is recommended that they be attached to alarms and strip chart recorders at points identified by the design engineer. 

In order to minimize the temperature variation effects on the differential manometer pressure measurements, the whole apparatus is immersed in an oil bath maintained in constant temperature, by means of a PID temperature controller. The bath temperature variations are minimized by insulating the space over the bath and keeping its temperature constant to 0.1 °C by means of a PD temperature controller and an air circulation fan. In addition, the room temperature over the insulating cover is kept constant to 1 °C. 

Because one of the products is a gas, we can monitor the progress of this reaction by measuring the pressure with a manometer. Pressure is converted to concentration using the ideal gas equation ... 

Nitrogen is admitted to a burette (5 in this case) and the mercury manometer pressure reading is taken. The gas is compressed to the next burette volume and the new reading taken. As with the helium the volume is reduced to the volume at STTP. Usually 2 or 3 readings are noted but more may be taken if desired (Table 2.3). Volumes should be reproducible to 0.02 mL. 

Figure I. A typical high-vacuum setup for Li. 22(NHj),TiS5- " synthesis. The manometer pressure gauge (either a capacitance manometer or a Hg manometer, preferably with a thin layer of ultra-low-vapor-pressure oil on top of the Hg column to suppress Hg volatility) is used to monitor the gas pressure and ensure the NH3 pressure does not exceed ambient pressure at any time.

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