LOTS OF FREE ONLINE CALCULATORS
This is an interesting page With a wide range of different calculators

GREAT ONLINE UNIT CONVERTER
This is an online unit converter and does almost everything one needs

ENERGY CALCULATORS
Chiller Flow rate and Energy Consumption KW/Hr Tons Calculator

FLOW RATE CALCULATORS
A calculator for flow metering that converts Velocity into Volume unit Flow Able to use on XP and Win 7 Desktops

Water Flow Calculator for Tubes and Pipes
But its an online flow calculator version built In php

CRUDE OIL CALCULATOR
A unique Calculator used to determine your losses in A crude oil batch due to varying amounts of water

PIPES PROPERTIES AND TABLES
This calculator  takes away the work  of having to Look up pipe dimensions, weight and other things A great time saver for mechanical engineers
Works on Windows

TECH EXPLANATION IN FLASH
This page has some interesting graphics designed in flash To explain the difference between a transit time and Doppler Ultrasonic flow meter