Working with SI (System International) Cylinders – Part 2

Womack Data Sheet 75: Working with SI (System International) Cylinders – Part 2

Download Data Sheet 

Piston Velocity – Metric Hydraulic Cylinders – For Pump Flows of 3 to 75 Liters per Minute

Piston Diameter mm.	Rod Diameter mm.	3 l/min.	5 l/min.	10 l/min.	15 l/min.	20 l/min	25 l/min.	30 l/min.	40 l/min.	50 l/min.	75 l/min.
25	None*	6.111	10.19	20.37	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
	12	7.938	13.23	26.46	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
	18	12.68	21.14	42.27	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
32	None*	3.732	6.220	12.44	18.66	Figures in the body of this chart are piston speeds in meters per minute (m/min).					– – – –
	14	4.614	7.690	15.38	23.07						– – – –
	22	7.077	11.80	23.59	35.39	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
40	None*	2.387	3.978	7.955	11.93	15.91	19.89	– – – –	– – – –	– – – –	– – – –
	18	2.992	4.987	9.974	14.96	19.95	24.94	– – – –	– – – –	– – – –	– – – –
	28	4.677	7.795	15.59	23.39	31.18	38.98	– – – –	– – – –	– – – –	– – – –
50	None*	1.528	2.547	5.094	7.641	10.19	12.74	15.28	20.39	– – – –	– – – –
	22	1.895	3.159	6.316	9.476	12.63	15.79	18.95	25.28	– – – –	– – – –
	36	3.174	5.290	10.58	15.87	21.16	26.45	31.74	42.34	– – – –	– – – –
63	None*	0.9624	1.604	3.208	4.812	6.415	8.020	9.624	12.84	16.03	– – – –
	28	1.199	1.999	3.998	5.997	7.995	9.995	11.99	15.00	19.82	– – – –
	45	1.965	3.275	6.550	9.824	13.10	16.37	19.65	26.21	32.74	– – – –
80	None*	0.5968	0.9947	1.989	2.984	3.978	4.973	5.968	7.961	9.943	14.82
	36	0.7483	1.247	2.494	3.742	4.988	6.236	7.483	9.982	12.47	18.71
	56	1.170	1.950	3.900	5.850	7.800	9.751	11.70	15.61	19.49	29.25
100	None*	0.3820	0.6366	1.273	1.910	2.546	3.183	3.820	5.095	6.364	9.549
	45	0.4790	0.7983	1.597	2.395	3.193	3.991	4.790	6.389	7.979	11.97
	70	0.7490	1.248	2.497	3.745	4.993	6.241	7.490	9.991	12.49	18.72
125	None*	0.2445	0.4074	0.8149	1.222	1.630	2.037	2.445	3.261	4.073	6.112
	56	0.3060	0.5100	1.020	1.529	2.039	2.549	3.059	4.080	5.096	7.646
	90	0.5076	0.8460	1.692	2.538	3.384	4.230	5.076	6.771	8.457	12.69
160	None*	0.1492	0.2487	0.4974	0.7460	0.9946	1.243	1.492	1.990	2.486	3.730
	70	0.1845	0.3080	0.6151	0.9227	1.230	1.538	1.845	2.462	3.074	4.613
	110	0.2830	0.4716	0.9432	1.415	1.887	1.358	2.830	3.776	4.714	7.074
200	None*	0.0955	0.1592	0.3183	0.4775	0.6366	0.7958	0.9549	1.284	1.591	2.387
	90	0.1197	0.1996	0.3991	0.5987	0.7982	0.9978	1.197	1.597	1.995	2.994
	140	0.1872	0.3121	0.6241	0.9362	1.248	1.560	1.872	2.498	3.119	4.681

Piston Velocity – Metric Hydraulic Cylinders – For Pump Flows of 100 to 450 Liters per Minute

Piston Diameter mm.	Rod Diameter mm.	100 l/min.	125 l/min.	150 l/min.	175 l/min.	200 l/min.	250 l/min.	300 l/min.	350 l/min.	400 l/min.	450 l/min.
		Figures in the body of this chart are piston speeds in meters per minute (m/min.).
80	None*	19.89	24.87	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
	36	24.94	31.18	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
	56	39.00	48.75	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –	– – – –
100	None*	12.73	15.92	19.10	22.28	25.46	– – – –	– – – –	– – – –	– – – –	– – – –
	45	15.97	19.96	23.95	27.94	31.93	– – – –	– – – –	– – – –	– – – –	– – – –
	70	24.97	31.21	37.45	43.69	49.93	– – – –	– – – –	– – – –	– – – –	– – – –
125	None	8.149	10.19	12.22	14.26	16.30	20.37	24.44	28.52	– – – –	– – – –
	56	10.20	12.74	15.29	17.84	20.39	25.49	30.59	35.68	– – – –	– – – –
	90	16.92	21.15	25.38	29.61	33.84	42.30	50.76	59.22	– – – –	– – – –
160	None	4.974	6.217	7.460	8.704	9.947	12.43	14.92	17.41	19.89	22.38
	70	6.151	7.689	9.227	10.76	12.30	15.38	18.45	21.53	24.60	27.68
	110	9.432	11.79	14.15	16.51	18.86	23.58	28.29	33.01	37.73	42.44
200	None	3.183	3.979	4.775	5.570	6.366	7.958	9.549	11.14	12.73	14.32
	90	3.991	4.989	5.987	6.985	7.983	9.978	11.97	13.97	15.97	17.96
	140	6.241	7.802	9.362	10.92	12.48	15.60	18.72	21.84	24.97	28.09

U. S. AND METRIC SI PRESSURE AND FLOW CONVERSIONS
for Operation of Air and Hydraulic Cylinders

PRESSURE						HYDRAULIC FLOW						AIR FLOW
PSI (lbs/sq. inch) and Bars						GPM and Liters per Minute						CFM and Cubic Decimeters per Sec
1 PSI = 0.0689655 Bar						1 GPM = 3.785 Liters per Minute						1 CFM = 0.47195 dm³/sec
1 Bar = 14.5 PSI						1 Liter per Minute = 0.2642 GPM						1 dm³/sec = 2.1187 CFM
PSI	Bars		Bars	PSI		GPM	l/min		l/min	GPM		CFM	dm³/sec		dm³/sec	CFM
20	1.379		1	14.5		1	3.785		5	1.32		1	0.472		5	10.59
30	2.069		2	29.0		2	7.570		10	2.64		2	0.944		10	21.19
40	2.759		3	43.5		3	11.36		15	3.96		3	1.416		15	31.78
50	3.448		4	58.0		4	15.14		20	5.28		4	1.888		20	42.37
60	4.138		5	72.5		5	18.93		30	7.93		5	2.360		30	63.56
70	4.828		6	87.0		10	37.85		40	10.6		10	4.720		40	84.75
80	5.517		7	102		15	56.78		50	13.2		15	7.079		50	105.9
90	6.207		8	116		20	75.70		75	19.8		20	9.439		75	158.9
100	6.897		9	131		25	94.63		100	26.4		25	11.80		100	211.9
120	8.276		10	145		30	113.6		125	33.0		30	14.16		125	264.8
140	9.655		15	218		35	132.5		150	39.6		35	16.52		150	317.8
500	34.48		20	290		40	151.4		175	46.2		40	18.88		175	370.7
600	41.38		25	363		45	170.3		200	52.8		45	21.24		200	423.7
700	48.28		30	435		50	189.3		225	59.4		50	23.60		225	476.7
800	55.17		35	508		60	227.1		250	66.1		60	28.32		250	529.7
900	62.07		40	580		70	265.0		300	79.3		70	33.04		300	635.6
1,000	68.97		45	653		80	302.8		350	92.8		80	37.76		350	741.5
1,200	82.76		50	725		90	340.7		400	106		90	42.48		400	847.5
1,400	96.55		55	798		100	378.5		450	119		100	47.20		450	953.4
1,600	110.3		60	870		125	473.1		500	132		125	58.99		500	1,059
1,800	124.1		65	943		150	567.8		550	145		150	70.79		550	1,165
2,000	137.9		70	1,015		175	662.4		600	159		175	82.59		600	1,271
2,250	155.2		80	1,160		200	757.0		700	185		200	94.39		700	1,483
2,500	172.4		100	1,450		225	851.6		800	211		225	106.2		800	1,695
2,750	189.7		125	1,813		250	946.3		900	238		250	118.0		900	1,907
3,000	206.9		150	2,175		275	1,041		1,000	264		275	129.8		1,000	2,119
3,250	224.1		175	2,538		300	1,136		1,100	291		300	141.6		1,100	2,331
3,500	241.4		200	2,900		325	1,230		1,200	317		325	153.4		1,200	2,542
4,000	275.9		250	3,625		350	1,325		1,300	343		350	165.2		1,300	2,754
4,500	310.3		300	4,350		375	1,420		1,400	370		375	177.0		1,400	2,966
5,000	344.8		350	5,075		400	1,514		1,500	396		400	188.8		1,500	3,178

Note that a “liter” is equal to a “cubic decimeter (dm³)” but the liter is used for liquid measure while the dm³ is used for air and gas volume measurement.

Note also that a “bar” is used widely in fluid power for pressure measurement, but the standard SI unit for pressure is the pascal (Pa) or the kilopascal (kPa). One kPa is equal to 0.00145 PSI, a unit which is difficult to work with in most fluid power systems.

© 1990 by Womack Machine Supply Co. This company assumes no liability for errors in data nor in safe and/or satisfactory operation of equipment designed from this information.

Download Data Sheet