No. The hydraulic cylinder would probably never go that fast. The fluid is under pressure when and only when the line is sealed. When the line is open somewhere, fluid would flow out gently because of low pressure. Only in a pneumatic system you would see the piston go so fast and the pressured air flow out so strong.

​@@khanhphaminh1175 can you translate your answer in terms of the alternating red and blue sides shown in the video for double action because I'm not following what you're saying. Also not sure if you're guessing since you said probably or if you definitely know.

​@@Redneck_Edin the double acting cylinder system, look at the tank (blue part under the pump). Near by it is the "line" (or pipe) that would never sealed (or closed) and it always open for fluid flow back to the tank. Next, see how slow the hydraulic piston move (not the pump in the left). Not so fast, right? So, the piston is slow, the pipe is open, so the fluid in the pipe have nearly zero pressure. Hope you understand because english is not my mother language

@@khanhphaminh1175 yes, thank you so much. Your English seems pretty good to me.

@@Redneck_Ed glad I can help!

I have one on both sides of the stick. Would I need to adjust both sides or just one side?

Thank you for watching our video. We are always happy to talk.

Good morning Nhlanhla Khumalo, Thank you for your comment. If you can use a single acting cylinder, the designer will be much simpler and cheaper. You do need gravity return or spring return to make it work. The design has to be reliable. For example, friction in pivots or slides over time could cause a problem. Also check that there is not a need to lock the elevator hydraulically for operational or safety reasons. That is difficult with a single acting ram. If it is a hand pump that you are using, the flows will be small. -4 or 1/4" sizes are often adequate on the pressure line, subject to the temperatures you are working at. There are lots of different elevators all with their own designs. Always have a look how other people do things first. Good luck on your project.

@@johnfoster8624 thank you so much is it okay if I ask you anymore questions that I may stumble upon

Good afternoon Oscar, That's a good question. I think I have seen pumps without the outlet non return valve. I think one of the Italian volume market pumps doesn't have it. We have put in this extra check valve for 40 years simply to provide that extra security. My instinct is to put it in for that reason. Thank you for the interest in our product.

Raka MS, Thank you for the view and question. Aircraft shock struts are complex because they mix oil and nitrogen. Not our thing, but this link may help. www.aircraftsystemstech.com/p/there-are-many-different-designsof.html . I thought that aircraft landing gear also used regenerative cylinders as well, which is worth looking into if you are designing hydraulic systems. I might be wrong. A regen cylinder can provide rapid extension- take a double acting cylinder and pressurise both ports. We've used them on some of our kit over the years for specific reasons. Our vid doesn't discuss them, just as we haven't talked about how telescopic cylinders work. Plenty of stuff on the web. Thanks.

Good morning James. Have a look at a garbage wagon or tail lift. Some hydraulic cylinders only need to be powered in one direction and use gravity or a spring to return them. Others need to be powered on the out and return strokes. That's the difference. It is a big thing for hydraulic designers.

@@johnfoster8624 ah i see. thanks a lot man

Radhika chauhan, thank you for watching our video and your comment.

Thank you - if you want any other topics covered, please let us know, and we'll see what we can do!

The pump shown in the video can go up to 100 bar, although we have different models capable of going up to 700 bar. Thanks for the question!

I just had the same question. thanks

Nick, make sure the drain from the needle is below the level of the oil in the reservoir and that the flow paths are big enough and you can do exactly what you say. Actuator manufacturers use this sort of method for damping or speed control. You can move the cylinder freely then add power when you need to. Keep in mind that if there is spring return, that can be a fair force to overcome. Thank you for the watch and the question. Sarum Hydraulics

@@johnfoster8624 Appreciate the answer John

Thank you, Yegi Uma. With more and more people having to mould from eco and reformulated plastics, burst testing is a big thing. Our kit is very cost effective.

Good morning Bingoman. Use the formula Pressure = Force/Area. If you know the pressure that your electric, air driven or hand pump will generate and you know the force as 200kgf, you can work out what area you need on the full bore side of the piston. Then look at standard rams to start with and select one with the right size. I would start with the Enerpac or HiForce catalogue. Those are 700 bar cylinders. Or you may be able to use a more basic ram from lots of catalogues, often running at 200 bar. Those will probably be cheaper. Lots of other considerations. Spring or gravity return? Or double acting? Mineral oil, water or something more specialist? interface on the ram body and piston rod? Materials? Good luck with sorting out the right cylinder for your application.

@@johnfoster8624 actually i wanted to design a stair to ramp convertor using double acting electric hydraulic cylinder that can lift 200kgf or more. what type of fluid should be used and can u suggest how to find the power?

@@johnfoster8624 Which works best on a hydraulic elevator that carries a load of 1000kg and what pipe diameter should I use for the pipes connecting from the pump to the piston?

Henrik, I would get a pair of verniers and measure the bore/shaft, the groove diameter and the length of the groove. Check the bore or shaft and see if it is IMPERIAL or METRIC. For me, that is a good start. You can then go through you seals data sheet and match up the width or the seal groove and the depth to a cross section of O ring. Remember that the depth of the groove will be the same for one cross section of o ring but the groove is wider if it has one or two ptfe/plastic/rubber anti extrusion rings. For example, an "O" series O ring is 1.46/1.52mm groove depth and 1.4/2.6mm groove width on hydraulic application for O ring alone, 1.10/4.23mm wide with a single backup ring and 6.10/6.23mm wide with two backups. It is all there in black and white. As soon as you find out what cross section it is e.g 2mm metric or 1.75mm for an O series O ring, you can move to the size tables and match the correct O ring. I would be very surprised if this does not match up very easily. I don't think many designers would guess at groove dimensions. Your o ring stockist can help you with this matching, but you will need to measure the part first. Good luck. You will need then to get the correct material grade, but find the right size first.

Good morning J land Malakas, That is a very good question for anybody who is designing equipment with a single acting cylinder. If you are lifting a very light load, the speed of descent might be quite slow and controlled . Or might it be "a bit slow" or "ridiculously slow." If you are lifting a heavy load using a single acting cylinder and when you release the pressure back to tank, it crashes down, totally out of control, that is a real hazard. That is unacceptable for lifting/jacking and anything to do with medical applications. Your can fit a fine needle valve into the feed to the hold release valve to adjust the speed of descent to what suits the application. But what about something like a hospital bed where one day you may have a baby on it and the next day a very heavy person? We use a pressure compensated flow control valve to control the speed of descent. As long as you get the right valve flow rate, that will keep the speed of descent safe and controllable. We would say that as well as doing your calculations to sort the correct pump and cylinder for a job, you should also check out the speed of descent and not just take a chance on it being OK.

Good morning Alvin, Thank you for looking at our video. If a manual jack is lifting a load and uses gravity return, it will invariably use a single acting cylinder as in our left hand view. You are pressurising the full bore area under the piston and lifting the load. You release this pressure back to tank when you want to lower the load. The right hand graphic showing the double acting cylinder does correctly show an acceptable graphic for four way two position directional control valve (a 4/2 valve.) We could have shown this as a circuit symbol for a spool valve, but our kit uses a very low leakage four way ball valve, so that explains more clearly exactly what our Micropac pump does. We hope that explains.

Jeremy, You can use a double acting pump with its two hoses to operate a single acting cylinder, but just connect one hose to the cylinder feed and feed the other hose back to tank. Pump the cylinder up then to let it down, turn the valve through 90 degrees to connect the cylinder to tank. The pump is more complicated and expensive than a unit with a simple hold release valve, but it does work. If you don't connect the hose to tank, the cylinder will simply not descend. It won't burst, provided it is rated to the correct pressure. Using a single acting pump to operate a double acting cylinder is another interesting question. Thank you for watching our video.

Mahendrathakor, thank you for watching our video.

Thank you Zulferi Syahputra for watching our video. We will explain the basics of cylinder calculations. These are just the fundamentals. A hydraulic cylinder is based on the formula Force =Pressure x area or rearranged, pressure = force/area. Work in pounds force and square inches or Newtons and square cm. We suggest not to mix metric and imperial units when calculating, but remember that you can simply convert pounds force into newtons at the final stage if you need to know an answer in imperial and metric units. 14.5psi = 1bar, 2.2lb=1kg, 9,81kgf=1 Newton and 25.4mm= 1 inch. Square for mm2 to inches2. Cube for mm3 to inches3. One more important point before you work out your cylinder force. A double acting cylinder is easy. The area applicable when the cylinder extends is the full bore area of the piston/bore it is running in. Use Area = pi x radius squared. On the area as the cylinder retracts, it is the ANNULAR area that you need to use. Work out the rod area and take that away from the full bore area, giving you the area of the annular “ring.” A single acting cylinder is very easy apart from one complication. Most designs will include some sort of piston to give the cylinder stability and also stop the rod popping out at full stroke. You MUST find out whether the hydraulic seal is in the bearing (so your area is that of the rod) or on the piston (so your area is that of the piston diameter.) This is fundamental. You have given us two diameters of 18mm and 10mm. The areas are 2.54cm2 (0.394in2) and 0.785 cm2 (0.122in2). Your load is quoted as 10kgf/22lbf (I am assuming), so the pressure is either 22/0.394=55.8 psi (3.84bar) or 22/0.122=180.3 psi (12.4 bar) depending upon the construction of the cylinder. Finally, how to work out the displacement or amount of fluid shifted over a full stroke. On a single acting cylinder, take the effective area (which you do unfortunately have to decide) x the stroke = so many cubic centimetres or cubic inches. A double acting cylinder simply uses the full bore area or the annular area x the stroke. Expect the displacement on the retract stroke to be around half of the extend displacement depending on the design. Your single acting cylinder has a displacement of 76.2cc/4.65cu.in. or 23.5cc/1.43 cu.in depending upon the effective diameter. Finally, look at the figures and check they are sensible. This is vital. If you are converting from mm to cm or ibf to newtons, people can easily make careless mistakes. I hope this very basic explanation in a few lines is helpful to you.

Sammy, thank you for viewing our video. A reservoir will normally breathe to atmosphere so you can take fluid out and put it back in. Some applications do use a breather bag on a reservoir or even seal the fluid in a rubber bladder. That is required when you are carrying kit around upside down and don't want oil to spill or you don't want dirty air or water to enter the reservoir, as in an underwater hydraulic system. You can leave an air space in a reservoir and have it sealed, but we are careful with this. We hope this explanation makes sense.

Thank you for your comment, Emilio. We will ask our designer.

Thank you for watching our vid, LUX 03. Engineering is our life. We're passionate about hydraulics. Keep watching.

Thank you AGS-Tech. We are pleased that you found this animation useful.