What is difference between orifice meter and Venturi meter?
A Venturi meter is designed to have three parts; the converging section, the throat and the diverging section. Pressure taps are provided before the converging part and at the throat in order to measure the drop in pressure. An orifice meter is consists a thin plate with a bore on the plate.
How does a venturi flow meter work?
A venturi works by measuring the difference in pressure at two different locations. The pressure difference is created by reducing the diameter of the pipe causing the fluid to flow faster. The fast moving fluid has a lower pressure than the slower fluid in the larger section of the venturi.
Do orifice and venturi meters directly measure flow rate?
Most recent answer. Measurement of mass flow rate of fluid in fluid mechanics is by meters (venturimeter, orifice meter) connected at the entrance and at throat by recording pressure drop by manometer. Out of these, venturimeter is found to be the most accurate device for measurement of mass flow rate.
How does an orifice flow meter work?
Basic Working Principle of an Orifice Meter
- The liquid or gas whose flow rate is to be determined is passed through the orifice plate.
- This creates a pressure drop across the orifice plate which varies with the flow rate, resulting in a differential pressure between the outlet and inlet segments.
How do you calculate orifice flow rate?
Then we have to calculate the flow range of the orifice plate….The plate thickness at the orifice edge should not be exceeded by any of the following parameters:
- 1 – D/50 where, D = The pipe inside diameter.
- 2 – d/8 where, d = orifice bore diameter.
- 3 – (D-d)/8.
Does an orifice reduce flow?
Orifice won’t decrease flow linear. It’ll just increase pressure upstream then get to a critical point before it reduces flow.
What is the purpose of orifice?
An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a restriction plate). Either a volumetric or mass flow rate may be determined, depending on the calculation associated with the orifice plate.
How do you identify an orifice in the pipeline?
An orifice tab is welded on the orifice plate which extends outer of the line giving an indication of the orifice plate.
What are the different types of orifice?
Types of Orifice Plates Used in Flow Measurement
- Concentric Bore Orifice Plates. Eccentric Bore – Eccentric bore orifice plates are plates with the orifice off-center, or eccentric, as opposed to concentric.
- Example of Eccentric Bore Orifice Plates.
- Example of Segmental Bore Orifice Plates.
- Example of Quadrant Bore Orifice Plates.
How do you make an orifice plate for piping?
Steps required to design an orifice plate or orifice plate flow meter:
- Identify the physical attributes of the piping system.
- Identify and accumulate data on process flow conditions.
- Identify and accumulate information on other requirements of the flow meter.
How do you design a restriction orifice?
Importance of restriction orifice sizing
- Types of restriction orifice. The RO should be selected based on the required pressure drop and flow rate.
- Factors for sizing RO.
- Pressure-controlling application.
- Flow-controlling application.
- Sizing to avoid sonic flow.
- Sizing to avoid cavitation.
- Sizing to reduce noise.
How do you size a restriction orifice?
Calculate cavitation index, Kd by equation (15), and compare with minimum allowable value. If cavitation index ≥ 0.37 (or 0.93), then the orifice diameter is acceptable. If the cavitation index < 0.37 (or 0.93), then a single orifice is unable to accommodate the required pressure drop.
How do you prevent cavitation in restriction orifice?
This phenomena is well known as cavitation. One way to avoid cavitation in restriction orifice is to reduce pressure drop across RO so that the pressure dip is maintained as high as possible. This results multiple restriction orifices to break the pressure drop in several steps.
What is the difference between flow orifice and restriction orifice?
An Orifice Plate is used to measure flow, while a Restriction Orifice is used to drop upstream pressure of a system. It is similar to an orifice plate but is thicker. While passing the fluid through thick plate energy is lost in friction and heat resulting considerable pressure drop.
What is the purpose of restriction orifice?
Restriction Orifice vs Orifice Plate
| Restriction Orifice | |
|---|---|
| Purpose | Used for killing the high pressure or reducing pressure; a pressure reducing device. |
| Hole Profile | The hole of the restriction orifice has a straight profile |
| Pressure Drop | High Pressure drop |
| Fluid Velocity | Sonic Velocity to ensure choked flow. |
What is an orifice on a human body?
An orifice is an opening or a hole, most often in the body, such as your mouth or your nostril. We most often use orifice to describe a natural opening in our bodies, but it can an opening into any cavity, such as a hollowed out tree trunk, or the vent of a heating system.
Why is an orifice plate beveled?
Orifice plates are beveled on the downstream side to help minimize the plate’s contact with the flowing gas stream passing through the meter. The amount of beveling required on plates of the same thickness decreases as the meter tube inside diameter (ID) increases.
How many types of orifice plates are there?
Three kinds
Which way does an orifice plate go?
Looking at the side-view of this orifice plate, the intended direction of flow is left-to-right, with the sharp edge facing the incoming fluid stream and the bevel providing a non-contact outlet for the fluid.
What is square edge orifice plate?
The square edge on the hole in an orifice plate helps to minimize contact with the fast-moving fluid stream going through the hole. Square-edged orifice plates may be installed in either direction, since the orifice plate looks exactly the same from either direction of fluid approach.
What is flow nozzle?
The flow nozzles is a flow tube consisting of a smooth convergent section leading to a cylindrical throat area. As mentioned above, flow nozzles are primary elements in differential pressure flow meters. These flow meters use the primary elements as an obstruction to generate a pressure drop to calculate the flow rate.
Why CD of orifice is less than mouthpiece?
In Venturi meter losses are less so coefficient of discharge is higher whereas in orifice meter due to no convergent and divergent cones there are more losses and hence its coefficient of discharge is less.In venturi meter losses are low due to steamline shape of the diffuser and the pressure gradient is not abrupt as …
What is the discharge coefficient of an orifice?
The discharge coefficient is a dimensionless number used to characterise the flow and pressure loss behaviour of nozzles and orifices in fluid systems.
How do I know my actual discharge?
KV Actual discharge = Actual area at B × Actual velocity at B = Cc × Cu A 2gH( ) we see that the relationship between the coefficients is Cd = Cc × Cu To determine the coefficient of discharge measure the actual discharged volume from the orifice in a given time and compare with the theoretical discharge.
How do you calculate discharge?
Measuring Discharge To calculate discharge, multiply the area of water in a channel cross section by the average velocity of water in that cross section. The simplest way to measure discharge is to divide the channel cross section into vertical rectangular subsections.
What is a discharge rate?
In this case, the discharge rate is given by the battery capacity (in Ah) divided by the number of hours it takes to charge/discharge the battery. For example, a battery capacity of 500 Ah that is theoretically discharged to its cut-off voltage in 20 hours will have a discharge rate of 500 Ah/20 h = 25 A.