Tuesday 1 October 2024

 1) Std Ideal Liq Vol Flow (standard input on Aspen Hysys)

Volumetric flow is calculated based on ideal mixing of pure component ideal densities at 60 °F (15 °C).

2) Liq Vol Flow @Std Cond
Volumetric flow is calculated rigorously at the standard reference state for volumetric flow rates, and reflects non-ideal mixing effects.

3) Actual Volume Flow (not a direct input in Aspen Hysys)
Volumetric flow is calculated rigorously at the flowing conditions of the stream (i.e., at stream T and P).

Direct and reverse acting

 


GWR st std conditions

 


std conditions

 Std conditions are 101.325 kPaa and 60F


15.6 deg c and 101.325 Kpaaa






 

Brackish and fresh water

 




Wednesday 18 September 2024

Cv and “Cf” of a valve

 Critical Flow Factor, often referred to as “Cf” is a coefficient that defines how pressure will recover after it drops to its lowest point inside the control valve. This lowest point is also referred to as the vena contracta*.

All globe-style control valves have a Cf that stays consistent regardless of the trim position, unlike the Flow Coefficient (Cv).

Note: The Pressure Recovery Factor (FL) also refers to the Critical Flow Factor in some literature.

What is Cf Used For?

Cf is a factor needed in order to calculate Flow Coefficient (Cv) or Flow Rate for valve sizing purposes. 


What is Valve Flow Coefficient (Cv)?

Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it.

It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”

As the stem opens, the Cv increases.

The maximum Cv for the 2-inch regulator is 47, while the maximum for the 3-inch regulator is 117.








Tuesday 17 September 2024

CWE

 Cold Water Equivalent means the barrels of steam expressed in terms of an equivalent cold water volume with the cold water density being 62.4 pounds mass per cubic foot.

999.5521145351039 kg/m3

Convert to mass flworate and then use that to determine the volumetric flowrate at the temp and pressure u desire

Bubbler Panel

Bubbler System Process

The bubbler system works by forcing a gas (compressed air) 

at a near-constant flow rate out the bottom of an open 

tube (bubble/dip tube) submerged in liquid. The back pressure 

in this tube is measured. With the process liquid’s density known, 

the level can be calculated using the back pressure and 

density. A pressure transmitter converts the back pressure to 

provide a 4-20ma output to a controller, which calculates 

the liquid’s level.

As the liquid level increases, the head pressure on the bubble tube gets higher. This means more pressure is needed to maintain a constant flow rate to overcome the pressure of the fluid.

If the fluid level goes down, so does the head pressure on the bubble tube and the pressure required to maintain constant flow rate of air or gas.  

To minimize maintenance requirements, we can add a purge line to clear the bubble tube of debris and buildup. This can be a manual operation with the push of a button, or automated with a purge schedule and timer.


https://www.instrumentationtoolbox.com/2014/06/bubbler-tube-system-for-level.html?m=0


https://automationforum.co/troubleshooting-advantages-disadvantages-and-application-of-the-bubbler-type-level-measurement-system/


Saturday 14 September 2024

pump types

Types of pumps

https://www.ny-engineers.com/blog/main-types-of-pumps

Fig.1. Pump classification.1









SUB-TYPE

DESCRIPTION

EXAMPLES

Reciprocating Pump

Flow is established inside a cavity that expands and contracts, such as a piston. Water moves into the cavity during expansion, and is forced out during contraction, while the flow direction is controlled by using check valves.

Bladder
Diaphragm
Peristaltic
Piston/plunger

Rotary Pump

This pump type uses a rotor that traps water in cavities, releasing it at the outlet. These cavities can be the spaces between gear teeth or screw threads, among other configurations.

Some designs use more than one shaft, but the principle is the same: the rotor shape is designed to capture “pockets” of water and displace them in the intended direction.

Gear
Screw
Progressing cavity
Rotary lobe
Rotary vane

SUB-TYPE

DESCRIPTION

PERFORMANCE

Axial Flow Pump

Also known as a propeller pump, it produces water flow along the impeller shaft direction.

High flow rate
Low pressure

Radial Flow Pump

This pump type produces flow in a direction perpendicular to the shaft (90° angle).

Low flow rate
High pressure

Mixed Flow Pump

This pump type combines radial and axial flow, producing a conical flow pattern around the shaft.

Medium flow rate
Medium pressure