From Fundamentals of Industrial Instrumentation and Process Control

Chapter 9: Humidity, Density, and Viscosity


The dry bulb of a wet/dry thermometer reads 120 F. What is the relative humidity if the wet bulb reads ( a) 90 F, ( b) 82 F, ( c) 75 F?


The wet bulb of a wet/dry thermometer reads 85 F. What will the dry bulb read if the relative humidity is ( a) 80 percent, ( b) 60 percent, ( c) 30 percent?


What is the relative humidity if the wet and dry bulbs in a wet/dry thermometer read 75 F and 85 F respectively?


The dry bulb of a wet/dry thermometer reads 60 F, and the relative humidity is 47 percent. What will the wet bulb read and what is the absolute humidity?


The wet and dry bulbs of a wet/dry thermometer read 75 F and 112 F, respectively. What is the relative and absolute humidity?


If the air temperature is 85 F, what is the water vapor pressure corresponding to a relative humidity of 55 percent and at 55 F with 85 percent relative humidity?


How much water is required to raise the relative humidity of air from 25 to 95 percent if the temperature is held constant at 95 F?


How much heat and water are added per pound of dry air to increase the relative humidity from 15 to 80 percent with a corresponding temperature increase from 42 to 95 F?


How much water does dry air contain at105 F and 55 percent relative humidity?


How much...

Products & Services
Humidity Transmitters
Humidity transmitters provide electrical outputs that are proportional to humidity inputs. They measure variables such as relative humidity, absolute humidity, specific humidity, moisture content, dew point, temperature, and pressure.
Research and Commercial Greenhouses
Commercial and research greenhouses are enclosures dedicated to the botanical needs of plants. Commerical greenhouses produce plants for consumers, while research growth chambers are oriented towards plant science and pharmaceutical harvests.
Weather Instruments
Weather instruments are designed to measure one or multiple components of weather including wind speed and direction, rain or snow fall, solar radiation, temperature, pressure and humidity.
Downdraft Tables
Downdraft tables are self-contained, portable filtration systems that remove harmful particulates and return filtered air.

Topics of Interest

Chapter 10: Other Sensors 1. What force is necessary to accelerate a mass of 17 lb at 21 ft/s 2? 2. What is the acceleration of 81 kg, when acted upon by a force of 55 N? 3. What torque does a...

Questions and Answers R-1 One hundred cu ft of air at 70 F dry bulb and 20 per cent relative humidity are passed through a spray chamber where it comes in contact with water at the...

Introduction Popular devices for humidity measurement include the hygrometer, a device which measures only relative humidity; thermohygrometer, a device which measures both temperature and humidity;...

In dealing with processes involving exchange of mass and energy between a liquid and an essentially insoluble gas, the principles of psychrometry are useful. Important operations to consider are the...

19.1 Introduction Psychrometrics deals with the thermodynamic properties of moist air, which is the final heat transport medium in most air conditioning processes. The use of psychrometric tables and...