Vacuum Chamber Suction Pressure: -100 Kpa or 0 Kpa?

Click For Summary
SUMMARY

The discussion centers on the pressure dynamics within a vacuum chamber when a valve is opened while a vacuum pump, rated at -200 KPa, is still operational. When the valve is opened, the initial suction pressure is determined by the atmospheric pressure (100 KPa) minus the pump's capability, leading to a suction pressure of -100 KPa. However, as air enters the chamber, the pressure differential decreases, influenced by the inlet valve size and the pumping rate. The discussion also explores the implications of connecting the inlet valve to a hose leading to a bucket of oil, which would alter the pressure dynamics further.

PREREQUISITES
  • Understanding of vacuum pressure measurements (KPa)
  • Knowledge of vacuum pump operation and specifications
  • Familiarity with fluid dynamics and pressure differentials
  • Basic principles of gas flow and valve mechanics
NEXT STEPS
  • Research the effects of valve size on vacuum chamber pressure dynamics
  • Learn about the principles of fluid dynamics in vacuum systems
  • Investigate the performance characteristics of vacuum pumps, specifically those rated at -200 KPa
  • Explore the implications of introducing liquids into vacuum chambers and their effects on pressure
USEFUL FOR

Engineers, physicists, and technicians involved in vacuum technology, fluid dynamics, and those designing or operating vacuum systems.

nastaynas
Messages
2
Reaction score
0
This is NOT a "problem", it's a rather a question.
Let's say I've got a vacuum chamber, and I suck the air out of it using a vacuum pump that is capable of doing -200 Kpa. Let's also say that there is a valve on this chamber. After a full vacuum has reached, I open this valve WHILE the pump is still running (thus creating a suction at the valve opening). What would be this pressure of suction? Is it -100 Kpa (100 Kpa which is atmospheric pressure, subtract 200 Kpa which is pump capability) OR is it just 0 Kpa since we are at vacuum?
 
Physics news on Phys.org
Initially the differential across the inlet valve will be 1 atmosphere (100 KPa).
Then the pressure in the chamber will rise so the differential will be less than 100 KPa. The amount will depend on the rate of flow in (how large the inlet valve opening is) and the rate of pumping out. The -200 KPa rating just means the pump can achieve a near vacuum when exhausting from a closed chamber to a 2 atmosphere destination - it says nothing about how much gas can be exhausted per second.
 
I see. Makes sense.
So let's say the inlet valve of 1/4" and the pump is also hooked up to a 1/4" outlet: does this mean that rate is the same thus the pressure difference remains constant?

What if the inlet valve is hooked up to a hose which leads to a bucket of oil (thus sucking the oil into the chamber)?
What would happen to the pressure inside?
 

Similar threads

Simple Gas Pressure Question - Combined Chambers Final Pressure
  • · Replies 13 ·
Replies
13
Views
3K
Conceptual thermodynamics question regarding specific heat ratio
  • · Replies 6 ·
Replies
6
Views
2K
Piston suction pump versus external gear pump as vacuum pump
  • · Replies 56 ·
2
Replies
56
Views
2K
Converting Voltage into Pressure
  • · Replies 24 ·
Replies
24
Views
3K
Undergrad Graduation of air flow inside a vacuum chamber
  • · Replies 4 ·
Replies
4
Views
3K
Mechanical pump oil discharge through inlet
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Volume of water consumed by vacuum
  • · Replies 5 ·
Replies
5
Views
2K
Vacuum pump design
  • · Replies 6 ·
Replies
6
Views
3K
Vacuum furnace argon fill system — advice needed
  • · Replies 3 ·
Replies
3
Views
849
Calculate vacuum loss by using principles of physics, not physical testing?
  • · Replies 8 ·
Replies
8
Views
2K