# What is Syringe: Definition and 49 Discussions

A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside of the tube, allowing the syringe to take in and expel liquid or gas through a discharge orifice at the front (open) end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle or tubing to direct the flow into and out of the barrel. Syringes are frequently used in clinical medicine to administer injections, infuse intravenous therapy into the bloodstream, apply compounds such as glue or lubricant, and draw/measure liquids.
The word "syringe" is derived from the Greek σύριγξ (syrinx, meaning "Pan flute", "tube").

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1. ### Mini linear actuator for syringe

Dear, I would like to create a controlled system to inject 1-2 ml of liquid (a chemical reagent) into a solution contained in a glass flask. The only request made is to use a reliable linear piston of minimum size, equal to or slightly larger than the injected volume (1 cm3) so that it can...
2. ### Damping and friction in syringe equation of motion

Hello Everyone I want to model forces affecting on syringe plunger , but I do not know how to calculate terms like friction and damping coefficient. What I imagine is that : F_driving = ma + cv + f ----------------(1) where: f: friction c: coefficient of viscous damping m: mass of plunger (is...
3. ### I What is the equation for calculating average gas flow in a compressed syringe?

Hi, I tried looking for similar topics but nothing really solved my problem. How can I calculate the average gas flow on a syringe that was compressed over time, if the starting and ending pressure and volume are known? I am guessing there must be an equation which can relate these variables...
4. ### Calculating force on a syringe plunger for a viscous fluid?

I'm currently working on a precise glue/resin dispenser, and I'm trying to derive an equation for the force one must exert on a syringe plunger as a function of the desired flow rate Q, and also accounting for the fluid viscosity and the syringe barrel and needle geometry. I've attached a scan...
5. ### Maximum number of microchannels in parallel for a syringe pump

Basically, I want to determine how many microchannels I can have in parallel to drive a fluid (for now assume water),without the syringe pump stalling. Let's say a syringe pump have a maximum linear force of 50 lbf. and I want to drive the fluid at 60 ml/hr. So if I have 4 parallel channels...
6. ### Kelvin-Planck 2nd Law of Thermo & a Syringe Steam Engine

So I found this steam engine on the youtubes: Consider the system not including the candles, only including the can that makes up the boiler shell and the piston, flywheel, etc. The boiler can acts as a hot reservoir; however, the Kelvin-Planck statement of the 2nd law says you can't have an...
7. ### I Liquid soap pulsing as it's drawn into a syringe

So here it is. I took a guess but I couldn't really answer, hopefully you can. Slow motion video of pulsations occurring while sucking liquid soap into a syringe.
8. ### The Time and Force Required to Empty a Syringe: What Does Science Tell Us?

Okay, so what I attempted for a) is to use Bernoulli's. The velocity of the fluid in the chamber should be equal to the velocity of the piston, which in comparison to the barrel should be negligible. Hence I get \frac{p_1}{\rho g} = \frac{1}{2} \frac{v_2^2}{2} + \frac{p_2}{\rho g} so \Delta...
9. ### Gas in a syringe being compressed - thermodynamic processes

1. Adiabatic compression (When compressed quickly, there is no heat flow to the environment Q=0) Isochoric with heat loss (The syringe is still compressed, there should be no change in volume) Adiabatic expansion (When the syringe is released, there is work done only) Isochoric with heat gain...
10. ### Friction coefficient and the force on a syringe plunger

I need to conduct an experiment and measure how what is the coefficient and force of friction of the rubber that pushes down along the edge inside the syringe. The thing is I can’t use a dynamometer.
11. ### Need help with horizontal syringe Bernoulli's Principle problem.

Did I do this problem correctly? I felt like I did this wrong because the answer is suppose to be around 50 m/s.
12. ### I Back to basics: bubbles in a syringe

Please could someone give me some idea of what is happening when you pull back on a syringe filled with fluid and the bubbles in the fluid (in the syring) expand? Let's assume it's water. How do the bubbles grow? I am assuming it is a rectified diffusion process where gas in the fluid is drawn...
13. ### Solving Fluid Dynamics in Syringe: Magnitude & Pressure

How would you go about solving the following problems regarding a syringe full of water? First, find the magnitude of force required to be applied to a piston of an 85ml syringe with a 60mm diameter tube to drain the tube in 25 seconds through an outlet of 10mm diameter? Second, what would the...
14. ### B Why Does a New Syringe Have an Open Piston?

Why the piston in a new syringe is not completely closed,,? Is it just because of to differentiate from New one or it just have a scientific reason
15. ### Calculating Friction Force for a Waterproof Seal in a Syringe Setup

Hi Friends, So I'll go into a bit of the setup that I'm having some trouble figuring out. I have a piece of rubber that will be pushing up against the side of a metal (or plastic) container to create a waterproof seal. The easiest way to think about this would be to imagine the rubber piece of...
16. ### Difficulty extracting fluid from balloon via syringe

Hello, New to the forum, so apologies if this is not the correct sub-category. I am testing compliances of materials by filling balloons with different fluids. I do this by filling up a 30 mL syringe with fluid and placing it into an infusion pump set to infuse at a rate of 0.1 mL/min. The...
17. ### The Relationship Between Volume and Force in a Sealed Syringe

Hello I had a question, related to a recent experiment we've done, that I have been thinking about for a while now. Hopefully someone can help as it has been bugging me! Consider two situations: A: a syringe is filled with 5ml of air and then sealed B: the same syringe but now filled with...
18. ### Syringe: Find force given volume and pressure

Homework Statement A 60 mL syringe filled with air is connected to a pressure sensor. The latter reads 100kPa. You then push on the piston until it stops moving. You now have 30 mL and the pressure sensor reads 200kPa. What force is used to keep the syringe rubber at the 30 mL mark...
19. ### General information on back pressure in a syringe

Hi all I'm looking for general information on "back pressure" specially in a syringe. So when you put your finger over the top of a syringe and depress the plunger then release the pressure on the plunger and the plunger moves back slightly. I'm struggling to find some specific information...
20. ### Fluid Dynamics - Pressure at the end of a syringe

Hello there Physics Forum! This is my first post here. This problem has been boggling me all day and I'm need of help in piecing together what I've come up with so far. I'm currently working on a personal project related to paint spraying. In this project I'm using a syringe & needle to feed...
21. ### Fluid Dynamics: Calculating Speed and Force in Syringe Experiments"

Homework Statement It is time for aged physics lecturers to have their flu shots but even that can be interesting. Assume the density of the vaccine in the syringe is the same as the density of water. The diameter of the syringe is 6mm, the length of the needle is 3cm and by reading the packet...
22. ### Calculate Flow Rate of a Syringe: Poiseuille's & Bernoulli's Laws

I am trying to come up with a mathematical model so that, when the displacement of the plunger of a syringe is know, I can calculate the amount of a specific liquid in the barrel. Or the relationship between the speed of the plunger and flow rate at the tip of the needle (Again assuming that the...
23. ### Negative Pressure in a 10mL syringe containing 2.5mL water

Hello All, We are trying to convert a vacuum leak test for medical devices (catheters) from a syringe based test to a pump based test. The current guidelines call for purging air from the ID of the catheter under test with water (~1mL). The distal end of the catheter (tube) is blocked and the...
24. ### Linear force of a syringe pump plunger

Hi all, I am looking for the correct calculation of the torque (or linear force) that is needed on a syringe plunger to overcome a backpressure at the nozzle of 20,000 psi. I have to decide which syringe pump I will be using for my application, but their is a lot of choice and mainly I need...
25. ### Positive/Negative Pressure Control of Syringe using Compressed Air and Vacuum Pump

I would like to try and set up a pressure control system in my lab using house vacuum and compressed air. Or otherwise using a compressed air source and vacuum pump. I want to be able to control the pressure in a reservoir (a syringe) within the range of -15 to +15psi. I was thinking...
26. ### Calculating Force Needed to Pull Plunger in Standard Syringe

I have a standard syringe 1” diameter, with a freely moving plunger requiring uniform force to move the length of the cylinder providing smooth uniform travel. Cross sectional area = ∏r2 = 3.1415 * 0.5” * 0.5” = 0.785 in2 Negative pressure acting on the piston = 0.758 in2 * 14.7 psi =...
27. ### Constant pressure in a heated syringe

Homework Statement When a syringe with its end sealed is heated, the piston is pushed back such that the gas pressure in the syringe remains the same. Since the force exerted is dependent on 1) frequency of collision with the walls and 2) the force of the collisions. So comparing before and...
28. ### Friction force calculation of syringe plunger

Hi all, This is my first post here. I finally decided to sign up after using the site for many years. I am working on a project involving a syringe mechanism. I am using a stock 6ml syringe. I'm trying to calculate the static friction of the rubber seal. I have measured both the pull...
29. ### Would a syringe in space suck?

Depends on how desperate you are? ;) This is a question of the nature of vacuums. Part 1- In the relatively pure vacuum of space, (for this case let's consider it pure please). Can volume of a closed chamber be increased or decreased without force? (other than the friction of materials, but...
30. ### Calculating Work for Removing Water from Syringe

A syringe is filled with water and placed in horizontal position. How much work should we do pressuring the clip with a constant force in order to remove the water from the syringe in a time t. The volume of the water in the syringe is V, the cross-sectional area of the opening is S1 and is very...
31. ### Pressure of fluid leaving a syringe

I am trying to find an equation to find the pressure of a fluid as it leaves a hypodermic needle when all I have is the diameter of the hole the fluid is discharging from and the flow rate. Can anyone point me in the right direction? I think this should be simple but I have spent a couple of...
32. ### Physics of a Syringe: Surface Tension & Water Retention

I was wondering, why is it that when water is "sucked up" by a syringe that this water stays inside the syringe and doesn't leak out?... Is this because of the surface tension of the water?
33. ### What is the ideal stepper motor for a Labview-controlled syringe pump?

Hi, I'm new into this forum. I'm planning to do a syringe pump controller to be used with a Labview software. As far as i know, precision flow rate movements higly depends on having the right stepper motor being used. Has anyone done anything similar on this? I'm looking for the right...
34. ### Archived Syringe Problem (Fluid Dynamics)

Homework Statement A hypodermic syringe contains a medicine with the density of water. The barrel of the syringe has a cross-sectional area of 2.5*10^-5 m^2. In the absense of a force on the plunger, making the medicine squirt from the needle. If the syringe is horizontal and the pressure...
35. ### What is the Net Pressure in a Syringe?

Homework Statement A nurse applies a force 4.35 N to the piston of a syringe. The piston has an area of 5.99x10-5m2. What is the pressure in the fluid within the syringe? Answer in kPa. Homework Equations mg/2A=\DeltaP The Attempt at a Solution 4.35/2*5.99x10-5= 36310.518 Pa...
36. ### Using labview to control a kent scientific genie plus syringe pump

i need to find a way to control the syringe pump in my lab so that i can control the flow rate in real time from the computer, ideally from a simple dial i scale up or down. the pump can connect to the computer using a rs-232 port and someone suggested to me that labview would be the easiest...
37. ### How Much Force Must a Nurse Apply to Overcome Blood Pressure Using a Syringe?

Homework Statement A 1.63 mL syringe has an inner diameter of 5.04 mm, a needle inner diameter 0.21 mm, and a plunger pad diameter (where you place your finger) of 1.06 cm. A nurse uses the syringe to inject medicine into a patient whose blood pressure is 140/100. What is the minimum force the...
38. ### What is the Minimum Force Required to Inject into a Vein Using a Syringe?

A syringe with a plunger of diameter 2 cm is attached to a hypodermic needle with a diameter of 2.1 mm. What minimum force (in N) must be applied to the plunger to inject into a vein where the pressure is 16 torr above atmospheric pressure. P=F/A since P will be constant throughout...
39. ### What is the minimum force needed for a syringe to deliver serum into a patient?

Homework Statement I'll just post the question given: You are at the clinic getting your flu shot. The syringe that is being used to deliver the vaccine has a volume of 2.0 mL, an inner diameter of 6.0 mm, and the needle has an inner diameter of 0.25 mm. The plunger on which the nurse has...
40. ### Syringe: probably a really simple mistake that I can't seem to catch

Homework Statement A syringe of volume 20 ml has just been used and now lies empty on the doctor's desk. The pressure in the office is 100,000 Pa. Assume that the air is an ideal gas consisting of nitrogen N2 (80%) and oxygen O2 (20%) molecules. k=1.38×10-23 J/K and the molar mass of oxygen...
41. ### Force and flow speed of a syringe

Homework Statement A 1.8mL syringe has an inner diameter of 5.6mm, a needle inner diameter of .26mm, and a plunger pad diameter (where you place your finger) of 1.0 cm. A nurse uses the syringe to inject medicine into a patient whose blood pressure is 140/100. a.) What in the minimum force...
42. ### Syringe Pump Manufacturing: Motors Used in Systems

What does it take to manufacture such a syringe pump? What kind of motor is usually used in these systems? http://www.macros.com.tw/p_kds.asp
43. ### Advantages of Larger Syringe Barrels for Aspiration & Pathology Removal

We need to figure out the advantage, if any, of using a larger diameter barrel syringe to aspirate fluid and pathology (cells, blood clot & tissue) from a patient using identical size catheters or needles. Lets ignore that, all things equal, it takes more force to pull back a larger plunger...
44. ### Solving Pressure of Syringe Homework Statement

Homework Statement A 2.0 mL syringe has an inner diameter of 6.0mm, a needle inner diameter of 0.25mm, and a plunger pad diameter (where you place your finger) of 1.2 cm. A nurse uses the syringe to inject medicine into a patient whose blood pressure is 140/100. a. What is the minimum...
45. ### Help with syringe pressure and Students T test

I am a doctor with limited mathematics knowledge. I am trying to prove to my medical fraternity that for a given force of aspiration, a smaller syringe generates a higher "negative pressure". I did a small experiment. I hung an one kilogram weight on a 5 ml and 10 ml syringe and connected it to...
46. ### Achieving a negative pressure with a syringe

I am a medical doctor needing some physics help. Quite often in patients we insert thin tubes into blood vessels for various purposes. These occasionally get blocked and we use syringes to try and clear these blockages. We attach a syringe and create a "negative pressure" by drawing back the...
47. ### Calculating Flow Rate in Syringe

Hi all, If I only know the Pressure given by a known Force on the barrel side of the syringe, the Density of the fluid, the Cross Section Area of the two parts of the syringe, the length of the syringe barrel and a ball with known Mass being pushed by the fluid flowing out of the syringe...
48. ### Calculating Pressure with Boyle's Law: 38 lbs of Books on 0.45 in^2 Syringe

So i looked up Boyle's and it said PV = C P= pressure V= Volume C= constant so my question is Suppose 38 pounds of books were balanced on a syringe plunger with a cross-section area of 0.45 in^2? A) how much pressure would just the books exert on the trapped air sample...
49. ### Calculating Water Velocity in a Syringe: Solving the Force and Pressure Equation

a force F of 2n is applied to a plunger with a crossectional area of 2.5*10^-5m, the area of the needle is 1*10^-8 sq meters, the static pressure every where is 1 atmopshere, it is horizontal, and it is filled with water. what is the velocity of the water exiting. please help. i know that the...