Each frame size for example frame T is built to specified dimensions. The amount of room required for the pump assembly will depend on the size and construction of the motor. It is easy to find a chart that provides the motor dimensions vs. A graphical representation of the laminar and turbulent Colebrook flow equations.
Gas[ edit ] Gases are compressible and change volume when placed under pressure, are heated or are cooled. A volume of gas under one set of pressure and temperature conditions is not equivalent to the same gas under different conditions.
Liquid[ edit ] For liquids, various units are used depending upon the application Flow along venturi tube industry, but might include gallons U. Primary flow element[ edit ] A primary flow element is a device inserted into the flowing fluid that produces a physical property that can be accurately related to flow.
For example, an orifice plate produces a pressure drop that is a function of the square of the volume rate of flow through the orifice. A vortex meter primary flow element produces a series of oscillations of pressure.
Generally the physical property generated by the primary flow element is more convenient to measure than the flow itself. The properties of the primary flow element, and the fidelity of the practical installation to the assumptions made in calibration, are critical factors in the accuracy of the flow measurement.
The stopwatch is started when the flow starts, and stopped when the bucket reaches its limit. The volume divided by the time gives the flow rate. For continuous measurements, we need a system of continually filling and emptying buckets to divide the flow without letting it out of the pipe.
These continuously forming and collapsing Flow along venturi tube displacements may take the form of pistons reciprocating in cylinders, gear teeth mating against the internal wall of a meter or through a progressive cavity created by rotating oval gears or a helical screw.
The piston meter operates on the principle of a piston rotating within a chamber of known volume. For each rotation, an amount of water passes through the piston chamber. Through a gear mechanism and, sometimes, a magnetic drive, a needle dial and odometer type display are advanced. Oval gear meter[ edit ] A positive displacement flowmeter of the oval gear type.
Fluid forces the meshed gears to rotate; each rotation corresponds to a fixed volume of fluid. Counting the revolutions totalizes volume, and the rate is proportional to flow. An oval gear meter is a positive displacement meter that uses two or more oblong gears configured to rotate at right angles to one another, forming a T shape.
Such a meter has two sides, which can be called A and B. No fluid passes through the center of the meter, where the teeth of the two gears always mesh.
On one side of the meter Athe teeth of the gears close off the fluid flow because the elongated gear on side A is protruding into the measurement chamber, while on the other side of the meter Ba cavity holds a fixed volume of fluid in a measurement chamber.
As the fluid pushes the gears, it rotates them, allowing the fluid in the measurement chamber on side B to be released into the outlet port. Meanwhile, fluid entering the inlet port will be driven into the measurement chamber of side A, which is now open.
The teeth on side B will now close off the fluid from entering side B. This cycle continues as the gears rotate and fluid is metered through alternating measurement chambers.
Permanent magnets in the rotating gears can transmit a signal to an electric reed switch or current transducer for flow measurement.
Though claims for high performance are made, they are generally not as precise as the sliding vane design.
These openings divide up the fluid stream and as the gears rotate away from the inlet port, the meter's inner wall closes off the chamber to hold the fixed amount of fluid. The outlet port is located in the area where the gears are coming back together.
The fluid is forced out of the meter as the gear teeth mesh and reduce the available pockets to nearly zero volume. Helical gear[ edit ] Helical gear flow meters get their name from the shape of their gears or rotors. These rotors resemble the shape of a helix, which is a spiral-shaped structure.
As the fluid flows through the meter, it enters the compartments in the rotors, causing the rotors to rotate. The length of the rotor is sufficient that the inlet and outlet are always separated from each other thus blocking a free flow of liquid.
The mating helical rotors create a progressive cavity which opens to admit fluid, seals itself off and then opens up to the downstream side to release the fluid.
This happens in a continuous fashion and the flowrate is calculated from the speed of rotation. Nutating disk meter[ edit ] This is the most commonly used measurement system for measuring water supply in houses.
The fluid, most commonly water, enters in one side of the meter and strikes the nutating disk, which is eccentrically mounted. The disk must then "wobble" or nutate about the vertical axis, since the bottom and the top of the disk remain in contact with the mounting chamber.
A partition separates the inlet and outlet chambers. As the disk nutates, it gives direct indication of the volume of the liquid that has passed through the meter as volumetric flow is indicated by a gearing and register arrangement, which is connected to the disk.
It is reliable for flow measurements within 1 percent. The turbine tends to have all the flow traveling around it. The turbine wheel is set in the path of a fluid stream.Sep 14, · INTRODUCTION The Venturi tube is a device used for measuring the rate of flow along a pipe.
A fluid moving through it accelerates in the direction of the tapering contraction with an increase in the velocity in the throat/5(24). Wikipedia defines the Venturi effect as: "The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe." Bernoulli's equation, together with conservation of energy shows that a stream of fluid moving through a .
Find your centrifugal pump easily amongst the 5, products from the leading brands (Lutz, Weir, SKF, ) on DirectIndustry, the industry specialist for your professional purchases. Venturi tube is used as flow meter in piping system and where Venturi effect is required.
Due to change in diameter from Venturi flow meter inlet to Venturi tube throat mean velocity is changing while weight flow rate remains constant. The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section or low speed flow of gas) along a streamline, is a tubular setup known as a Venturi tube or simply a venturi.
Fluid flows through a length of pipe of varying diameter. a short tube with a tapering constriction in the middle that causes an increase in the velocity of flow of a fluid and a corresponding decrease in fluid pressure and that is used especially in measuring fluid flow or for creating a suction (as for driving aircraft instruments or drawing fuel into the flow .