Further, the direct acting duplex has the great advantage over a fly-wheel pump of not suffering breakage if water gets into steam cylinder. 3. SIZES OF PUMPS. _a._ Only the four different sizes given on the next page will be recognized for “National Standard” pumps. The multiplicity of odd sizes of “Trade Pumps” is confusing, and different makers have, in the past, estimated the capacity in gallons according to different arbitrary standards. NATIONAL STANDARD PUMP SIZES. ======================+=======+=============================== | Ratio | Capacity Pump Sizes. | of | At 100 lbs. | Piston| at Pump. ------+-------+-------+ Areas.+----------+--------+----------- Steam.| Water.|Stroke.| | Number of| Nominal| Actual | | | | 1-1/8 in.| Gals. | Gals. Per | | | | Streams. | Per |Min. as per | | | About | | Minute.| Art. 4. ------+-------+-------+-------+----------+--------+----------- 14 × 7 × 12 |4 to 1 | =Two= | =500= | 4830 14 × 7-1/4 × 12 | | | | 520 ----------------------+-------+----------+--------+----------- 16 × 9 × 12 |3 to 1 | =Three= | =750= | 8060 ----------------------+-------+----------+--------+----------- 18 × 20 × 12 |3 to 1 | =Four= | =1000= | 9990 18-1/2 × 10-1/4 × 12 | | | | 1050 ----------------------+-------+----------+--------+----------- 20 × 12 × 16 | 2-3/4 | =Six= | =1500= | 1655 | to 1 | | | ----------------------+-------+----------+--------+----------- NATIONAL STANDARD PUMP SIZES.(continuation) ======================+===============+================ | [B] Boiler | Pump Sizes. | Power | Full Speed. | Required | ------+-------+-------+------+--------+-------+-------- Steam.| Water.|Stroke.|Horse | Steam | Rev. |Piston | | |Power.| Pres. | Per |Travel | | | |at Pump,|Minute.|Feet Per | | | | lbs. | |Minute. ------+-------+-------+------+--------+-------+-------- 14 × 7 × 12 | 100 | 40 | 70 | 140 14 × 7-1/4 × 12 | | | | ----------------------+------+--------+-------+-------- 16 × 9 × 12 | 115 | 45 | 70 | 140 ----------------------+------+--------+-------+-------- 18 × 20 × 12 | 150 | 45 | 70 | 140 18-1/2 × 10-1/4 × 12 | | | | ----------------------+------+--------+-------+-------- 20 × 12 × 16 | 200 | 50 | 60 | 160 | | | | ----------------------+------+--------+-------+--------