Questions tagged [hydraulics]

Questions about the flow and use of fluids.

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63 views

Is there a mechanism that allows this kind of piston/plunger movement?

I am trying to create a prototype for a gravity energy storage system, and I need to release potential energy stored in a heavy load of mass M, raised to a height *H. I intend to use the mass ...
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6answers
75 views

Why are hydraulic systems widely used to multiply force ? won't a couple of gears do the job?

Hydraulic systems seem to have become ubiquitous. From huge cranes and excavators to disk brakes to door hinges. Basic requirement everywhere is the need to multiply force; trading greater force for ...
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Can an AC compressor used as a Hydraulic pump?

Can a car ac compressor be used as a Hydraulic pump ? Does it require some modifications to do so or is it impossible to begin with and the compressor can't handle the oil?
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556 views

How to lift an antenna tower into position?

I am considering getting a 100-ft antenna tower for mounting a weather station. However, the problem is how to erect it. It needs to be easily to lower in case I need to service the weather station. I ...
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58 views

Mathematical model of an hydraulic jack

How to find a mathematical model of this hydraulic jack system? I'm confused about the part when the piston extender, check valve 1 opens and check valve 2 closes, then liquid from the bottom tank ...
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3answers
75 views

Q: Could you siphon an 10 meter tall water column?

This question might be better suited for this stack. In the physics stack, I posted about a question about siphoning. https://physics.stackexchange.com/q/677102/259268 An 10 meter tall cylinder is ...
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2answers
38 views

Is a Tesla Valve a good fit for this requirement (prevent heavy load accidentally crashing downard but less restriction otherwise)

I want to design a hydraulic platform that allows/ensures: The GRADUAL DESCENT of a heavy load (e.g. a FULL shipping cargo container) from a height H1 to height H2 (where H1 > H2) - without the ...
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19 views

Everyday examples of hydraulic pressure drop generating heat

I'm interested in hands-on examples of voltage drop in electronics dissipating the energy as heat, and, thought that the hydraulics analogy, that is the same thing, might be a good way to intuitively ...
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multiple sequencing circuit for sequence A+B+B-C+C-A- by Cascade method

I am learning pneumatic circuit and i came across this problem of Designing and draw the multiple sequencing circuit for sequence A+B+B-C+C-A- by Cascade method for the Pneumatic system. the sequence ...
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3answers
73 views

Why actuators are mounted in inverted position?

Hope you are doing good. Can anyone please explain to me why actuators are mounted in inverted position on some excavators? Please see the image for better understanding of my question. Another ...
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1answer
77 views

Resistive divider hydraulics analogy, is this true?

The formulas for hydraulics and electricity are generally the same (theoretically), or for any type of flow. Air, water, hydraulic fluid, electrons... As shown on this website, a "hydraulic ...
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29 views

Adding electric control to industrial hydraulic disk brakes

I'm trying to electronically control the service brakes on some construction equipment, in addition to maintaining the normal brake pedal functionality. The disk brakes are controlled by the valve ...
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62 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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2answers
38 views

HPU minimum oil temperature

Two different HPU systems in different locations with slightly different oils Chevron Ranco HD 68 and HDZ 68 have the same minimum oil temperature 55. Their flash points are are 455 and 414 F ...
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46 views

What's the most efficient air compressor to reliably deliver up to 15 litres per second at 10 bar? [closed]

Suppose I wanted to continuously supply up to 15 litres of air per second, compressed to 10 bar - what would be the most efficient type of compressor, i.e. the type requiring the least energy input in ...
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40 views

Help calculating discharge rate from a reservoir as the water level drops?

I could do with some help calculating the discharge rate from a reservoir and factoring in how that flow will decrease as the head of water decreases. The information I have is: Maximum height of ...
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1answer
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How does hydraulic pressure booster works?

This photo shows hydraulic booster used in HPHT Hydraulic Press. I could not understand its function. How does this pump boost the hydraulic pressure ? Thanks.
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1answer
47 views

How to compensate for losses in a hydraulic system?

I have an engine ( 72240 kW... ) , probably the biggest internal combustion engine in the world and this engine has no camshaft. Instead it has an hydraulic system which controls the combustion, the ...
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31 views

Working out location of a hydraulic jump

This is the question I am working on: And here is part of the working i don't understand: I don't understand the process of plotting the profile - the little crosses marked on the diagram, how do ...
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1answer
49 views

Component selection type for fluid-mechanical system

I am creating an enclosure and need to get a water supply through a plastic wall inside to the core device. I imagine this water line will be a flexible tube and will screw on or snap to an adapter on ...
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67 views

Hydrostatic transmission to directly translate movement

I have been thinking about small hydrostatic transmission to directly translate movement of stepper motor (NEMA 17-23 size, geared with 3:1 or 5:1 ratio). My design currently involves 2 identical ...
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1answer
30 views

What is the side way force on a flat membrane place perpendicular to the flow of current on one side, and stagnant water on the other

So basically imagine a plate being placed parallel to the direction of flow of water with water flowing with a certain velocity on one side of the plate and on the other side it is almost stagnant. ...
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2answers
86 views

Pumps' geometric similarity

Given two pumps that are similar : $H_1=70-1.41x10^{-3}Q_1^2$ $H_2=100-1.1x10^{-3}Q_2^2$ Find the geometric scale : $\frac{D1}{D2}= ?$ I am also given maximum efficiency = 1. I tried solving but I got ...
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138 views

Boundary layer thickness decreases as fluid velocity increases, so why is the boundary layer thicker in the turbulent region for higher velocities?

I am modelling transitional fluid flow over a flat plate, and investigating the effects of free stream velocity on boundary layer thickness. From what we have been told, increasing free stream ...
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51 views

Why is the head loss in submerged pipe is 0

Looking at this question : Point C head loss is 0 according to the author Bottom right Can’t understand why , any good explanation for this claim ? Look at page 33 at the top
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1answer
27 views

Will decreasing a pump's flow rate decrease the NPSHR?

I have a small open hydraulic system and I simply need to circulate hot (85C) water from the bottom of a reservoir back into the top at ~4GPM. At its lowest point the system has only 3ft of static ...
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2answers
130 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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1answer
105 views

Running Hydraulic Pump with High Torque Motor

It's my understanding that hydraulics are merely a means of gear reduction to move a given object. So then I'm wondering why I can't find a formula or way to determine the following issue: I want to ...
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3answers
114 views

I cannot properly understand the "pressure" referred to in Bernoulli's Principle despite my efforts

I get that with Bernoulli's Principle an increase in area = a decrease in velocity = an increase in pressure. I also understand the concept of pressure being force per unit area. My difficulty is with ...
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2answers
86 views

How is high static water pressure avoided in municipal water systems?

Most cities get their water supply from local sources (springs, rivers, lakes) so the pressure in the system is never more than what is produced by the pumps. But some cities get their water from ...
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1answer
65 views

Low maintenance device to trade flow rate for lift height?

Is there a compact device which can trade flow rate for lift height without too many moving parts? My particular application is a 10 meter deep and 10 centimeter wide well with shallow water level, ...
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1answer
56 views

Hydraulic system dynamics modelling

I'm trying to mathematically model an actuation system and it comes down to relating the pressure across the pump and the actuator as shown in the picture. Assuming no friction in the pipes and the ...
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1answer
123 views

Circuit to provide position control for double action hydraulic actuator

I was wondering how to construct a hydraulic circuit to control a hydraulic double acting piston/actuator enabling the electronic control of the piston extension. I have found the following pneumatic ...
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2answers
44 views

Hydraulic energy recovery for high-pressure, low flow (non-steady state) conditions

What would be the best way to implement hydraulic energy recovery while de-pressurizing a pressurized volume of silicone oil initially at 1500 bar. Can a piston pump be concievably repurposed as a ...
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1answer
82 views

Running a hydraulic pump below minimum RPM

If I had a pressure compensated, hydraulic piston pump, how might the performance look in terms of pressure if I were only looking in the regime of 0 RPM and the minimum ratedRPM? I.E If a pump was ...
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40 views

What voltage are these hydraulic valves and how to I control them?

I am building a new control system for an injection moulding machine, the last part I am trying to work out is the main pump. It has two proportional valves on the output, one labelled throttle valve ...
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Volumetric oil pump efficiency goes up when viscosity goes down?? Strange behaviour

Riddle me this : we are driving an external gear pump (this kind) at a fixed RPM. At start, when the oil temperature is low (and viscosity high), the volumetric flow is much less than when the oil ...
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1answer
65 views

Why would these hydraulic cylinders have 3 large connections?

I am trying to work out how a recently acquired Arburg 220-90-350 from 1982 works so that I can build a new control system and get it working. It's a direct clamping machine with no toggle. The ...
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How to get this hydraulic system working and help identifying parts and their function

I have recently acquired a 1982 Arburg 220-90-350 injection moulding machine, mainly just as a hobby to further my knowledge on injection moulding machines and control systems as I plan to modernise ...
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1answer
35 views

Brake selection problem

I have a quick question guys. I am gonna select a brake but I am not sure. A Crane Hoist motor has a rating of 300 HP and maximum speed of 1800 rpm. This motor is attached to a gearbox with a perfect (...
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1answer
32 views

Effect of flow through a static hydraulic pump on its RPM

What happens when fluid flows through a static hydraulic pump? Will there be a negative RPM to impede the flow? By static pump, I mean a pump with initial RPM = 0.0 and is not driven by external ...
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1answer
228 views

Head loss for T junction diverging water pipes

I am writing to ask for help with a T-junction pipe problem. Attached picture shows the pipe configuration. The schematic shows a large pipe with ID 16.5mm and smaller 4mm ID tubes connected to it. ...
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Hydraulic lift connected to two pistons

I just finished a problem, and got the correct answer, however I am confused on one of the mathematical operations that must be performed in order to get the correct answer. The problem is as reads: ...
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2answers
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Stop Spa-to-Pool Siphoning Thru Spa Pump

I have a partially above ground Spa and an in-ground pool. When the spa is filled to spillover with pumps off, water siphons through the spa pump and into the pool until the spa water level drops ...
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Does a single-wheel brake intervention from ESC cause one wheel to be not brakeable by the driver?

Source: https://www.kfz-tech.de/Engl/Buchprojekte/HBremse/ESP3.htm Firstly, I don't know if this is the right StackExchange, but I will try nevertheless. Above I posted a picture of the hydraulic ...
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What specific technical concerns exist for China's Three Gorges damn on the Yangtze river?

Recently, many people (specifically geopolitical and financial analysts) have pointed out that there is a serious concern about China's Three Gorges Dam breaking and causing catastrophic flooding that ...
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Replicate stepper motor with gasoline engine

For those unaware of what a DC stepper motor is, it boils down to an electronic motor where the rotation can be precisely controlled, i.e. you can control the rotation of the motor in fractions of a ...
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480 views

hydraulic Motor/pump minimum speed

I have seen in many data sheets of Hydraulic Gear motor a spec called : "Minimum Speed = 450 RPM" ( 450 is an example) here is a capture from the linked datasheet below : In your experience ...
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How would you go about calculating the force required for an actuator to lift a bridge?

I have been trying to come up with the optimal way to calculate the force required for an actuator to be able to lift a bridge 90 degrees. (A drawbridge) The actuator is placed as follows: (The bridge ...
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How do I calculate Pressure drop across relief valve and then force on piston?

So, I'm designing a basic downhole hydraulic tool cutter of an OD = 5 1/2 in., and my tool contains a relief valve and a piston. I am trying to calculate pressure drop across the relief valve so that ...