
                      Using HydraCyl ver. 1.2x
                      _______________________

                            E X A M P L E
                            _____________



We have included an example of a hypotetical design to ilustrate the
step by step procedure involved in HydraCyl.

Design specifications are:

*    Cylinder Duty                 Heavy

*    Cylinder Bore Dimension             2   inches

*    Cylinder Rod Dimension              1   inch

*    Cylinder Stroke                    34   inches

*    System Flow                        25   litres/min

*    Pressure                           60   bar

*    Attached Mass                    2300   kg

*    Cylinder - Valve distance         150   inches

    (The length of pipes between the Cylinder's ports and the Solenoid
     valve)

*    Cylinder Mounting Type             Intermediate trunnion

*    Mounting Orientation               The applied massis permanently
                                        attached to the piston rod stud
                                        and Cylinder rod extends and
                                        retracts

*    Spacial orientation                35   deg

*    Coefficient of Friction             0.15

*    Hydraulic Line Dimensions           6   mm (outside diameter)
                                        'L'  series





1.      Run HC.EXE
2.      Choose 'OK' on form 'About'
3.      Choose 'Analysis'
4.      Choose 'Perform Analysis'

You will get a message: 'Cylinder Dimensions must be specified'

5.      Choose 'OK'

Let's say you want a heavy duty 2"/1" cylinder

6.      Click on '( ) Heavy' in the 'Cylinder's Duty' box
7.      Click on Cylinder Bore Diameter 2.00
8.      Click on Cylinder Rod Diameter 1.00
9.      Click on 'OK'
10.     Choose 'Analysis'
11.     Choose 'Perform Analysis'

You will get a message: 'Cylinder Operating Parameters must be
                         specified'

12.     Choose 'OK'

Let's say the stroke of your cylinder is 34 inches, firstly you
need to et the correct units.

13.     Choose 'Change Units'
14.     Click on '( ) inch' in the 'Stroke' box
        (this will be the default unit for stroke until you 
        change it back to 'mm')
15.     Click 'OK'

Now you can enter the stroke.

16.     Click in '[_     ] inch' under the 'Stroke' heading
17.     Type 43  (OOPS my typing mistake, should be 34)
18.     Click on 'Clear Values'
19.     Click on 'Stroke'
20.     Type 34 (correct value)

Let's say the system flow is 25 lit/min

21.     Click in '[_     ] lit/min' next to the 'System Flow' heading
22.     Type 25

Let's say the Pressure is 60 bar

23.     Click in '[_     ] bar' next to 'Pressure'

        (if it is required change units to 'bar' in the simmilar
        maner as stroke.)

24.     Type 60

Let's say the attached mass is 2300 kg

25.     Click in '[_     ] kg' next to 'Applied Mass'
26.     Type 2300

Let's say the pipeline length between Cylinder's ports and solenoid
valve is 150 inches

27.     Click in '[_     ] inch' next to 'Cyl-Valve distance'
28.     Type 150
29.     Click 'OK'
30.     Choose 'Analysis'
31.     Choose 'Perform Analysis'

You will get a message: 'Cylinder Mounting Type must be specified'

32.     Choose 'OK'

Let's say the cylinder mounting type is 'Intermediate trunnion'

33.     Click on 'View Basic Mount Types (a - p)'
34.     High resolution picture is shown of all possible mounting
        types. Look for Intermediate trunnion. It is marked by 'b'
35.     Press any key to get out of diagram.
36.     Click on 'b0'
37.     Click 'OK'
38.     Choose 'Analysis'
39.     Choose 'Perform Analysis'

You will get a message: 'Cylinder Mounting Orientation Must be
                         specified'

40.     Choose 'OK'

Let's say a mass of 2300kg is permanently attached (cylinder rod
extending and retracting) to cylinder. Cylinder is mounted under 35
degrees slope, and mass is attached to Piston Rod Stud. Friction
coefficient is 0.15.

41.     Click on 'View Orientation Diagrams'
42.     High resolution picture is shown of all mounting orientation
        types. Look for above description. It is marked as '3'
43.     Press any key to get out of diagram.
44.     Click on '3'

45.     Click in '[_     ]' next to 'Angle between OX and OZ axis'
46.     Type 35

47.     Click in '[_     ] kg' next to 'Coefficient of friction'
48.     Type 0.15
49.     Click 'OK'

50.     Choose 'Analysis'
51.     Choose 'Perform Analysis'

You will get a message: Hydraulic Line Dimensions must be specified

52.     Choose 'OK'

Let's say that Hudraulic line between Cylinder port's and Solenoid
valve are 6mm outside diameter and 'L' series.

53.     Choose 'Metric'
54.     Click on Outside Diameter Size 6
55.     Click on Series L
56.     Click on 'OK'
57.     Choose 'Analysis'
58.     Choose 'Perform Analysis'

You will get a message: 'Calculation Complete'

(this means that all relevant data has been entered and now you will
see the results of HydraCyl's analysis)

59.     Choose 'OK'

You get a Warning:  SUPPPLY PRESSURE  Required pressure for                              Cylinder's extending is low, consult Page 5.

60.     Observe top left corner of the screen. There is title:
        Cylinder Data - Page 4 of 5.

61.     Choose 'Page Down'
62.     Observe Min.Total Pressure Rod Extending = 87.00 bar

Now we will make changes to our specifications to try to
overcome this design problem.
                                      
63.     Choose 'Cylinder' (on top left hand side of screen)
64.     Choose 'Operating Parameters'
65.     Change 'Supply pressure to 90 bar.
66.     Click 'OK'
67.     Choose 'Analysis'
68.     Choose 'Perform Analysis'
69.     Choose 'OK'

You will get a Warning: ROD BUCKLING Rod is buckling. Select larger
                        cylinder or use other engineering methods.
                        Consult pages 2 and 3.

70.     Observe top left corner of the screen. There is title:
        Cylinder Data - Page 4 of 5.

71.     Choose 'Page Up'
72.     Browse pages until you get page 2 on the screen.
73.     Play between pages 2 and 3 and observe values of:

        (page 2) Extending Force =  1824 daN
        (page 3) Column Strength  =  585 daN

Obviously that actual extending (static) force is almost 4 times
higher than Piston Column strength. Now we will make some changes to
our specifications to try to overcome this design problem.


74.     Choose 'Cylinder' (on top left hand side of screen)
75.     Choose 'Dimensions'
76.     Click on Cylinder Rod diameter 1.375".

(we have just changed cylinder rod diameter from 1" to 1.375" to
 try to eliminate buckling effects)

77.     Click 'OK'
78.     Choose 'Analysis'
79.     Choose 'Perform Analysis'
80.     Wait until you get a message 'Calculation complete'
81.     Choose 'OK'

At last NO Warnings. That means all parameters are acceptable and
properly entered. You have selected a suitable cylinder.

Let's look at the analysis results. Use 'Page Up' and 'Page Down' to
browse the inputs and results on the 'Cylinder Data' form, they are as
follows:

Dimensions:
         Bore Diameter       2.00  inch       (This is the cylinder
         Rod Diameter        1.375 inch        size you have now selected  
         Stroke             34.00  inch        for your application)

Hydr.Line Dimensions:
Pipe (Tube) Diameter         6      L
  Cyl-Valve Distance       150.00  inch

Mounting:
       Duty      Heavy
       Type  b0  MT4: Intermediate trunnion

Orientation  3   Fixed Cylinder Body. Piston Rod retracting and
                 extending. Load attached to Piston Rod Stud.

       Cylinder's Slope      35.00  deg
   Friction Coefficient       0.15

 Operating Parameters:

            System Flow      25.00  lit/min
        Extending Speed     205.58  mm/sec
         Extending Time       4.20  sec
       Retracting Speed     389.83  mm/sec
        Retracting Time       2.22  sec

        Supply Pressure      90.00  bar
    Max Pressure Rating     138.00  bar

        Extending Force    1824.00  daN
       Retracting Force     962.00  daN

       Column Strength    2091.00  daN
          Applied Mass    2300.00  kg

Other Analysis Results:

             Stop Tube       2.00  inch

 Extending Return Flow      13.18  lit/min
Retracting Return Flow      47.41  lit/min

          System Power       3.75  KW

             Bore Area       3.14  sq.inch
              Rod Area       1.48  sq.inch
          Annulus Area       1.66  sq.inch

Displacement Volume:

         Cylinder Head     0.9230  litre
          Cylinder Cap     1.7504  litre
                 Total     0.8273  litre

Warnings:
                        No Warnings.

Undamped Natural Frequency, Minimum Acceleration/Deceleration Time,
Distance and Pressure.

Natural Frequency Rod Extending            9.9    Hz
Natural Frequency Rod Retracting           9.9    Hz

Minimum Ramp Time Rod Extending            0.38   sec
Minimum Ramp Time Rod Retracting           0.38   sec

Min.Travel Distance Rod Extending          1.6    inch
Min.Travel Distance Rod Retracting         3.0    inch

Min.Total Pressure Rod Extending          87.00   bar
Min.Total Pressure Rod Retracting        -36.00   bar


Fluid Flow Velocity Through Pipe (Tube)

   Cylinder Rod Extending
       Cap End Pipe                       33.16        m/sec
       Head End Pipe                      17.49        m/sec

   Cylinder Rod Retracting
       Cap End Pipe                       62.88        m/sec
       Head End Pipe                      33.16        m/sec

Deceleration Device:

      Braking Distance     Head End Pressure    Cap End Pressure
             inch                 bar                  bar

              0.50                  53.00               163.00
              0.75                  41.00               141.00
              1.00                  35.00               129.00
              1.25                  31.00               122.00
              1.50                  29.00               118.00
              1.75                  27.00               114.00
              2.00                  26.00               112.00

       Ŀ
                 Braking Diagram - High Resolution          
       


Conclusions:
============

Stop tube of 2 inch must be mounted in your cylinder.

Although pump (System) delivered flow is only 25 lit/min, command
hydraulics block (solenoid valve and other components) should be
dimensioned on nominal value of flow 47.41 lit/min. If you neglect
this data you could not expect to get all speeds in your application.

When Cylinder's rod is retracted on that side you need 0.923 litre of
oil. When Cylinder's rod is extended on that side you need 1.7504
litre of oil. For proper work of cylinder you need only 0.8273 litre
of oil in your power unit (reservoir). That is total value of oil that
is required by cylinder for proper 'breathing'.

If you are in need to implement proportional device, you should
consider ramp time longer than 0.38 sec. Under those conditions, the
attached load requires at least 1.6 (respecively 3.0) inch travel
distance for its acceleration/deceleration from zero to maximum
(maximum to zero) corresponding speed.

On the page 5, you could read up:

     Min.Total Pressure Rod Retracting = -36.00   bar

Due to fact that negative apsolute pressure is nonexistent one (in the
nature), the sign '-' is only pointing to absolute pressure of 36 bar
at the cylinder cap end port generated by attached mass and friction
forces only. In other words, you should have the relief valve in that
line during acceleration and deceleration and adjust its value to 36
bar. In such way you will be able to control acceleration and
deceleration of attached mass during rod retracting.

Stroke-Braking Pressure Chart (Deceleration Device)
---------------------------------------------------

By observing this chart (numerical data are given on page 7) you are
able to rapidly determine correlation between generated braking
pressure and accompanied braking stroke.

Due to fact that braking pressure at Cylinder's Head End is under 138
bar (maximal pressure rating for choosen cylinder), that side of
Cylinder should be supplied with standard cushion. On the other side,
Cap End should be supplied with standard cushion only if its length is
slightly over 3/4 inch (red and green lines intersection). For that
length, the maximum pressure rating (red line) and generated braking
pressure (green line) are at the same value.

You can easily obtain information on standard cushion length (braking
stroke) and maximal pressure rating from your favourite supplier of
cylinders. Just enter those data on the chart and you will get
information on what would happen in the cylinder. Generally, for any
value of braking stroke between 1/2 inch and 2 inch you are able to
determine actual braking pressure.


Fluid Flow Velocity Through Pipe (Tube)
---------------------------------------

If we analyse the Fluid Flow Velocity Through Pipe (Tube) we may
observe that fluid is pushed throught pipe (tube) at enormous high
speed.  It should be maintained  around 4m/sec (13 ft/sec).  A bit
experiment, by changing pipe sizes can successfylly bring this high
flow velocity to around 4m/sec. For example. If we chooes Pipe 18mm
series L,  the flow will be:

Fluid Flow Velocity Through Pipe (Tube)

   Cylinder Rod Extending

       Cap End Pipe                        2.36        m/sec
       Head End Pipe                       1.24        m/sec

   Cylinder Rod Retracting

       Cap End Pipe                        4.47        m/sec
       Head End Pipe                       2.36        m/sec


Please, observe page 5 of 6. There will be:

Undamped Natural Frequency, Minimum Acceleration/Deceleration Time,
Distance and Pressure.


Natural Frequency Rod Extending            6.9    Hz
Natural Frequency Rod Retracting           6.9    Hz

Minimum Ramp Time Rod Extending            0.55   sec
Minimum Ramp Time Rod Retracting           0.55   sec

Min.Travel Distance Rod Extending          2.2    inch
Min.Travel Distance Rod Retracting         4.2    inch

Min.Total Pressure Rod Extending          85.00   bar
Min.Total Pressure Rod Retracting        -39.00   bar


You may recognise the different results form previous one when pipe
6mm had chosen!  The conclusion.  Pipe diameters has huge influence
in overall cylinder behaviour.  Minimum total travel distance jumped
from 4.6 to 6.4 inches. The barking pressure (rod retracting) jumped
from 36 to 39 bar, while required minimum total pressure lowered from
87 to 85 bar.  As it can be seen, by changing only one parameter in
the hydraulic circulit some crucial data my change in such manner to
bring the whole system on the brink of the functionality.

                   ------  end of file ------

