Questions tagged [pressure]

Questions pertaining to pressurized systems and their applications, from containment to system losses to using as a benchmark for measurement.

55 questions with no upvoted or accepted answers
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736 views

Estimating Maximum Speed for a Pneumatic Cylinder

I am designing an machine that is going to use a pneumatic cylinder to accelerate a projectile. I have a tentative cylinder specified, and am working on the control and supply side. I have verified ...
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61 views

Injecting CO$_2$ into water: how does injection work?

I've been wanting to design my own water carbonation device for a while. For reference, I've been looking at devices like the Sodastream, which injects pure CO$_2$ into water to dissolve it with up to ...
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17 views

Parts needed for controlling vacuum line pressure with pressurized nitrogen

I'm trying to assemble a simple setup where a line which is typically under vacuum can be pressurized by an external nitrogen supply, with this pressure regulated to less than 1 bar absolute (let's ...
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57 views

Generating a plasma via induction coil

I am trying to see if I can generate a plasma from an induction coil that is wrapped around a glass jar under vacuum. Tons of induction coil heatering circuits are on ebay for forging that can supply ...
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1answer
126 views

Equivalent Force: Hydraulic rams in H frame machine press

A 100ton H frame machine press can use 1x100 ton ram to exert this amount of force. Can 3x33 ton rams do the same job if they are applied to same area as the 100ton ram? Also in relation to a H ...
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499 views

Calculating engine pressure from measureable quantities

How can I calculate the engine pressure in units of Bars by using torque, the cylinder volume, motor efficiency, and the gear reduction ratio? My values are as follows: ...
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22 views

Using Density Correction Factors for Fans and Blowers

I've been researching fans/blowers and their use in pneumatic systems (particularly conveying systems), and I'm confused by the application of density correction factors. Let me describe a sample ...
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21 views

Compact way to regulate 3000psi (200bar) down to 30psi (2bar)?

This was originally posted on the Lego page, and closed because it's not actually about Lego itself. I thought I'd give them a chance first, in case someone had done this already and had some ...
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34 views

maintenance of steady flow through pressure or mass flow

let's say I have two points in a line, A and B. Between them there is a valve that can regulate the amount of the stream from A to B. Considering that there is a steady flow of the stream between A ...
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29 views

Reference book for hydraulic systems design

I'm looking for a good reference book on the topic of fluid dynamics/hydraulics systems engineering. I'd like a reference for simlpe/estimate calculations on things like major losses (pipes), minor ...
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142 views

How to calculate the flow rate of a gas through a pipe?

I am trying to calculate the flow rate of Nitrogen through a cylindrical pipe. I only need a ballpark value, and the only information I have is the inlet pressure as 15 psig (assuming the same ...
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20 views

Oil pressure inside copper tube?

**Background ** I'm struggling finding how to calculate the pressure that occurs within my system and then once calculated I need to reduce that pressure. My system I have a 1 inch copper pipe ...
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18 views

Calculating the water pressure knowing the circuit that tracks it

I'm not very good at physics, but I've got a problem that I really need to solve. On the second picture you can see a pipe with flowing water. The point of this mechanism is to lit a LED whenever the ...
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20 views

Turbocharger boost control using two valves with a vac and boost reference for wide boost control range

Can someone explain how the above boost control setup would work. The valve on the left uses a vac source applied to the top of the diaphram which would effectively help hold the spring closed at high ...
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19 views

Valve advice for chiller test rig

I am in the process of designing a chiller test rig, of which a very simplified diagram would be (the quick coupling might just be replaced by a non-return valve): I am struggling to find the type of ...
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28 views

Low pressure Diesel pumping with High pressure Gasoline pump?

We are in desperate search of suitable pumps for one of our applications. We need to be able to pump Diesel fuel in a range going from 5bars to 125bars. To do such thing, I've been looking at Bosch ...
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56 views

Hydraulic motor sizing

16 Examples of Tensile Strength has a list of items and their tensile strength. bamboo has these tensile strength ratings Bamboo MPA 350 PSI 50,763 If I needed to have a hydraulic motor to shred ...
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1answer
83 views

Manually Attempting Empirical Measurement of Flour Dough Compressive Strength

I want to make a DIY dough press, so need to know how much pressure I would need to apply. I don't have mechanical engg background, so based on some googling, I think this is what I need to do, but ...
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38 views

Choosing a blower for a Pneumatic Conveyor

Basically we are designing a pneumatic conveyor system for transferring 11 tons of beans per hour. We need to decide on the specifications of the blower. What are the calculations necessary to decide ...
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1answer
194 views

Pneumatic cylinder: Pressure rating

I want to create a Pneumatic cylinder, The purpose is, Inside it will will contain a Nylon piston, and one end will be filled with clay. Cylinder will be closed from either side using end caps, which ...
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20 views

How to analytically estimate the pressure loss through an liquid injector?

The simple orifice and a pipe have well-documented pressure loss calculation. But when an injector has complicated flow patterns, is it possible to break it down into simpler sections by which the ...
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27 views

Overcoming gravity with fluid pressure

How would I determine if an upward flow of liquid at 100 bar forces a bed of porous solid upwards or flows through without affecting the same bed of material? Is it related to bulk density and pores?
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35 views

multiple wall, pressurized gas pressure vessel

I was thinking about interesting powder metallurgy method, hot isostatic pressing. Often thick steel walled vessel is required increasing costs and decreasing the prevalence of this technology. This ...
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22 views

Determination of delivery pressure from pump in my Parts Washer

We want to know how can we determine the pressure of the liquid at the delivery end of the pump. We have a centrifugal pump and a 2" pipeline at the delivery end. Pump delivery performance as per ...
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96 views

Did the pressure unit “bar” change definitions since the 1930s?

I don't see anything in Wikipedia about it, but (from this question) when I try to reproduce the equations in this 1933 paper, I get values 106 away from the values in the paper. When I reproduce ...
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96 views

Adjusting the pressure of the condenser and the evaporator

The picture below shows a refrigeration unit I was reading the operation manual of this unit. It is written that the pressure of the condenser is controlled by the water flow rate. Reducing water ...
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26 views

Hugoniot Equations and Impact Pressure

I have a wave propagation question that regards two materials impacting each other. The question asks to find the impact pressure of the impact with a tungsten carbide flyer and a steel target. I ...
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3k views

Calculating discharge on the pipe diameter and the pressure?

Is it possible to сalculate discharge / flow rate on the pipe diameter and the pressure (for constant pressure)? For example: Pressure_internal = 5 bar, ...
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330 views

Latent heat of fusion of water near triple point

When a thermally isolated vessel of liquid water is depressurized to vacuum, part of water will evaporate, remainder will freeze - total heat being split between latent heat of ice and enthalpy of ...
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44 views

How to convert permeation units to molecules/second?

How do I convert $\dfrac{\text{cm}^3\cdot\text{mm}}{\text{m}^2 \cdot \text{day} \cdot \text{atm}}$ for permeation of gas through EVOH to molecules of gas permeating per second as a function of ...
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77 views

Contact pressure - screw pretension

I'd like to calculate the max contact pressure in the below assembly, just before contact loss between the beam and the wall. The beam is clamped to the wall with a pretensioned screw, and sustaining ...
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1answer
64 views

How to calculate flowrate of water through a crosssection of pipe?

Assume we have a pipe with a diameter of 10mm. Water is flowing through that pipe and we know that the water pressure at the 'open' end of the pipe is 2 atm. How would one go about calculating the ...
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27 views

Increasing suction air flow with multiple pumps

I'm trying to build a small pick and place system using a suction cup and a 12V vacuum pump. The problem I'm having is that I'm not getting a good enough seal between the cup and the object, and I ...
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28 views

N2O/Kerosene Rocket Fuel

I am interested in building a small liquid fuel rocket and I have decided to use nitrous oxide and kerosene as the oxidiser and fuel respectively. I would like to know if anyone has any advice ...
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35 views

Can Flowmaster be used to model an entire pipe run?

I just started using the Flowmaster program (ver 08.11.01.03 if relevant) to model a series of stormwater pipes which are almost certainly in a pressure flow situation based on a first round analysis ...
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22 views

Determining the minimal needed wall thickness between two bores in a control block

Given a control block of simplicity with only two bores. These two bores could be parallel or just could be very close to each other at a specific point in the control block. The material of the ...
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1answer
74 views

Pressure recovery in turbomachinery

Diffusers in turbomachinery are used to transfer some of the kinetic energy of the fluid to pressure energy and to direct the fluid to the ducting/second stage/... I understand this and the mechanism ...
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1answer
53 views

Liquid delivery to a pump based on viscosity

I have a tank that is filled with a viscous liquid (~3000 CPs). At the bottom of the tank there is a pipe that leads to a gear pump. There is 22" of pipe straight down from the tank followed by a ...
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12 views

Minor losses in a header

I need to calculate the minor losses in a steam header. I have calculated the major friction losses. But I can't figure out how to find the minor losses since the header has multiple tappings and not ...
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229 views

Matching Air blower CFM vs HEPA filter CFM, and ΔP in WG, for laminar flow design

I am trying to build a laminar flow box using instructions at these YouTube links for design and build. They recommended getting a Dayton squirrel cage air blower model 1TDU2 rated at 1202 CFM. The ...
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1answer
90 views

Kinetic energy of a balloon

How do I quantify how much kinetic energy would be released from popping a balloon? I believe that any additional kinetic energy that results from the balloon will come from it being pressurized, but ...
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27 views

Use of Absolute vs. Differential Pressure Transducers to Calculate Flow Through Annular Restriction

If using a laminar flow element, in conjunction with Poiseuille's equation, to calculate mass and volumetric flow rate, what would the benefit be to using two absolute pressure transducers to measure ...
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1answer
57 views

Reduce and compute flow in self designed pen

I am currently designing a simple pen for drawing with different types of liquid varnishes. My current design has a tip at the bottom side of the pen (blue) and a tank at the top side where the ...
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302 views

How to calculate the register draught/draft loss (RDL) of a burner?

I am aware this is a vague question but it is something which has been on my mind. Would anybody know the steps used to calculate the draught loss across a burner in the furnace of a boiler? Would ...
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1answer
213 views

using air pressure as a liquid pump

I have a $100\ \text{psi}, 300\ \text{cfm}$ air compressor that we use for running power tools, I need a way to inject mortar deep into a small opening and was wondering if anyone had experience with ...
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1answer
476 views

Estimate PSI from pipe diameter and GPM

Many consumer grade pressure washers specify a minimum pressure for the supplied water, which is sometimes well above the low end of household water pressure. Our water pressure is often low and I'm ...
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46 views

Long-term storage of a gas?

Can this formula be used to evaluate the minimum thickness of a spherical pressure vessel that holds hydrogen gas at 10 ATM for a long time? $$\sigma = \dfrac{p r}{2 t}$$ I was told, "As long as you ...
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62 views

Safety factor for pressurized container at 10 ATM

There is no secondary containment to hold any potential shrapnel. How would this change the safety factor that is standard at 2.5? The consequences of this container exploding would be quite extreme ...
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352 views

Why is there negative static pressure in contour?

I studied a paper about turbine and i seen that there is negative static pressure in contour. Why does this happen? Wave Energy Harvesting Turbine: Performance Enhancement
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2answers
137 views

How does placement of a pressure gauge in a tank of fluid affect the pressure readings?

This is not a real system but rather something I made up to understand how the placement of pressure gauge in a tank takes its readings. Here’s a diagram of it- The pressure gauge placed in the ...