Questions tagged [pressure]

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

80 questions with no upvoted or accepted answers
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17 views

What types of materials can be tested in a split Hopkinson pressure bar?

A split Hopkinson pressure bar can test different types of specimens, I would like to know what types of materials that are suitable to be tested with this method?
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86 views

Part to pierce the valve on a 16g CO2 cartridge and connect to a Solenoid valve

The specific part that I’m after is something that can connect to a solenoid valve and a CO2 cartridge that will break the seal on the end of the CO2 cartridge. The solenoid valve connection is ...
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981 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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62 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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18 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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59 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
141 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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506 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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8 views

Pv Diagram of a pressure cooker

For a bit of self training in thermodynamics, I've been trying to think of some random systems and go ahead and try to solve them, some of these things I've stolen from random googling of university ...
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36 views

Why is a throttling valve isenthalpic whilst a nozzle is not?

From my understanding, Nozzle's and throttling valve are devices which both trade pressure for velocity, so they increase velocity at the expense of having to decrease the pressure. If we examine ...
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43 views

Calculating discharge from a reservoir as the head of water decreases

Due to the dry weather we've been experiencing in the UK I need to calculate the discharge rate from some reservoirs for work and how the dropping water level will result in a reduced head and so a ...
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25 views

What is a safe and efficient temperature range for absorption chiller generators?

I've read that the role generators play in the absorption chiller cycle is to concentrate the salt solution so that the evaporator/absorber can maintain a vacuum by constant absorption of vapour ...
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1answer
94 views

How does steam in almost vacuum condense at 35 Celsius?

I read about absorption chillers and found out that the water is evaporated/boiled off at the generator. Water boils over at about 3.7 Celsius in the near-vacuum conditions in the generator. Now the ...
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1answer
97 views

Calculating Minimum Pipe Pressure Requirement for an Irrigation System

I am setting up an irrigation system for my ranch and I have a hard time calculating the minimum pipe pressure requirements to reduce cost. I need to know the maximum pressure the pipe has to cope ...
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47 views

Which of these propeller configurations is most efficient?

All propellers shown in the figure above are identical and are operated at identical speeds with four separate (numbered 1 through 4 vertically) configurations illustrated. The physical distance ...
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0answers
31 views

Why can't I find a small vacuum fryer?

I'm looking for a vacuum fryer and so far the only ones available to buy are large, industrial machines. Is there some technical consideration that makes small scale machines economically unfeasible? ...
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1answer
41 views

Does pressure in a centrifugal compressor increase along the path of the flow?

Euler turbomachinery equation doesn't include a term for changes in flow area. But, an centrifugal impeller (not the volute) has increasing flow area along the path of the flow. Is the pressure ...
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28 views

Is there a relationship between temperature and pressure of a refrigerant?

When searching for a pressure temperature relation for a refrigerant a chart appears. But I was wondering are these charts made by experimenting on the refrigerant or is there a relationship which can ...
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3answers
93 views

Can you shape a buoyant object stuck to the bottom of a body of water such that it floats?

I understand that an object, say a closed plastic cube full of air, stuck to the bottom of an aquarium with a smooth glass bottom will not float if you firmly place it such that no water can get ...
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1answer
60 views

Ceramic pressure measurement - piezoelectrical or capacitive?

Context: I'm writing about an old industrial training facility used for a petrochemical process. In this training facility, there is a 3-phase separator. On that separator is a pressure measurement. ...
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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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35 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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70 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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1k 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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22 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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1answer
109 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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22 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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0answers
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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0answers
30 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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0answers
60 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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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
301 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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1answer
68 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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0answers
21 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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0answers
29 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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36 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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0answers
23 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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0answers
99 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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112 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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0answers
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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0answers
364 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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0answers
91 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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54 views

Why is pressure in a common rail fuel system so much higher than in an air compressor or supercharger?

Superchargers in cars are bulky, expensive, consume considerable amount of engine's power and yet they generate only about 6-9 psi boost. On the other hand, modern common rail diesel engines inject ...
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0answers
32 views

Controlling flow through an output pipe

I wish to limit my flow through the output to a certain exact value. In this case to 10 lpm, what method or valve can I use to this task? At the moment the flow keeps on fluctuating between 10.1-11.2 (...
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21 views

In a high pressure water pump what component or design parameter increases pressure output, let's say from 200 atm o 2000 atm?

type of flow? length or diameter of the plunger piston?, or weight of the piston and crankshaft and torque or HP to move it?, or RPM. direct drive pumps used in waterjet cutting use a slim plunger ...
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78 views

Root cause investigation: spike in spray rate from a pressurised vessel

The purpose of this rig is to transfer water from the pressurised vessel to the upper tank where it is sprayed via V3 (see image). Under normal operation, the 2.5L transfer pipe is attached to both ...
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43 views

Suggestion for headgear

I was surfing through the web to find any article about why boxers don't like headgears. Then some random website claimed that a headgear doesn't absorb the punches moreover they limit vision. So I ...