Product and Application Information
This catalog presents the models primarily in ascending order of free air flow,. The table below will assist you in locating a particular model or series.
POWER RATING FREE AIR FLOW MAXIMUM MAXIMUM MODEL/ @ 60 Hz cfm m 3 /h PRESSURE VACUUMSERIES hp kW 50 Hz 60 Hz 50 Hz 60 Hz psi bar " Hg mbar
How does a Rocking Piston pump work?
8R (DC) - - 3.4 lpm 22.5 1,55 17 43820R (AC)
1 /
30 1 0,025 14 lpm 35 2,41 21 30230R (DC) /
30 1 0,08 0.61 1,04 120 8,2834R(DC) /
10 0,175 0.08 1,36 200 13,8 --- 55R (PSC•)
1 /
20 0,04 .16 .25 0,27 0,34 30 2,1 24 20055R (DC)
1 /
10 0,07 .25 0,42 30 2,1 24 200LOA (ShP••)
1 /
16 0,05 — .50 — 0,85 100 6,9 24 200LOA (PSC•)
1 /
6 0,12 .52 .83 0,88 1,41 100 6,9 26 133LOA (DC)
1 /
10 0,07 .62 1,05 100 6,9 27 99LAA
1 /
6 0,12 1.5 1.5 2,55 2,55 50 3,5 29 31SAA (Staged)
1 /
6 0,12 — 1.75 — 2,97 — — 29.5 14SAA (Parallel)
1 /
6 0,12 — 3.30 — 5,60 — — 27 99SAA
1 /
6 0,12 — 1.95 — 3,31 30 2,1 — —ROA (ShP••)
1 /
8 0,09 1.1 1.25 1,87 2,12 100 6,9 26 133ROA (PSC•)
1 /
4 0,19 1.5 1.60 2,55 2,72 100 6,9 27 99ROA (DC)
1 /
8 0,09 1.5 2,55 — — 26 133RAA
1 /
4 0,19 2.5 2.7 4,25 4,59 100 6,9 27.5 8271R/72R (1 Cyl.)
1 In reciprocating motion, a flexible cup mounted on top of the connecting rod creates vacuum or pressure as the cup maintains a seal against the cylinder walls in a rocking motion. /
3 0,25 2.1 2.4 3,57 4,07 100 6,9 — —71R/72R (2 Cyl.)
1 /
3 0,25 5.5 5.5 9,35 9,35 25 1,7 29 3171R (2 Cyl.)
1 /
2 0,37 1.7 2.0 2,89 3,40 175 12 — —74R
1 /
4 0,19 1.30 1.5 2,21 2,55 100 6,9 — —75R
1 /
3 0,25 4.5 5.1 7,65 8,67 40 2,8 27 9981R (2 Cyl)
1
Product and Application Information
/
3 0,25 3.5 4.0 5,90 6,80 100 6,9 — —82R (2 Cyl)
1 /
3 0,25 4.0 4.0 6,80 6,80 30 2,1 — —82R(DC) (2 Cyl)
1 /
3 0,25 3.2 3.9 5,4 6,60 30 2,1 25 16785R
1
Unit Life Expectancy
/
3 0,25 3.7 3.7 6,29 6,29 30 2,1 — — PSC – Permanent Split Capacitor motor ••ShP – Shaded Pole motor
Starting Under Load
The figures stated in this catalog are nominal ap-proximations for models without accessories. Intake filters and exhaust mufflers, and the accumulation of contaminants in them during operation, will decrease the flow of air as well as the achievable pressure. ROC-R® units will not start under load because the surface area of the piston is much larger than that of a piston pump. To start a ROC-R® unit un-
der load would require a motor too powerful to be cost effective. Instead, a specific volume of air at zero pressure differential must be provided to start the unit under load. (Specific volumes for different models are available from Gast.) Bleed orifices and dump valves are two common methods of supplying the correct zero-pressure-differential volume of air.Installation It is important to include a vacuum gauge at the vacuum pump inlet or a pressure gauge at the
compressor discharge in the air line within a few inches of the unit. Diagnosis of sys-
tem problems is easier and more accurate with a gauge at this location. In reciprocating units, a “snubber” should be installed in the gauge con-
nection to reduce pulsations which can damage the gauge.The installation of a relief valve is equally im-portant. Unit life is directly related to duty levels and most systems require only a fraction of the pump’s advertised capacity to operate efficiently. The Gast (optional) relief valve makes it simple to “fine tune” the pump to minimum system needs, reducing electrical consumption and maximizing pump life.
o F (O
o C) to 100
Continuous vs. Intermittent Operation
o F (38
o C). Low temperature affects the unit’s ability to start and high temperatures affect its life. Contact the factory for authorization of unusual ambient conditions.2. Duty level 3. Operating cycle
4. Operating speed
5. Condition of air handled • Cleanliness • Humidity • Heat • Chemical vapors present (corrosive, noncorrosive) 6. Unit maintenance • Lubrication (if required) • Filter maintenance • Muffler maintenance Continuous vs. intermittent duty usually must be considered. Duty usually must be considered. Our definition of intermittent duty is 10 minutes or less on and 10 minutes or more off. Here again we are dealing with a very general statement. A better method of deter-
mining if the unit is applied properly is to measure temperatures of the metal portion of the unit that surrounds the discharge port and top dead center of the electric motor. Please note that when you refer to performance curves in this catalog, the solid line indicates continuous operation, while the dashed line shows intermittent duty. In systems where storage of built-up vacuum is important, check valves should be installed between the pump and the system.
Electric Motors European Community’s Machinery Directive
All electric motors supplied with Gast rocking piston pumps are designed to operate at plus or minus 10% of nameplate voltage. Motors to meet special requirements are available upon request. Various brand-name motors are furnished on any model at the discretion of Gast. Given its international perspective, Gast has also pledged to conform to the European Community’s Machinery Directive, a safety certification program for all products targeted for marketing in the Euro-
pean Community. Currently, all Gast products sold in the European Community are in compliance and include a Declaration Certificate.
Catalog Performance Specifications
The specifications listed are that of a unit at sea level with an ambient temperature of 70°F (21°C), operating with normal electrical current conditions.
Many variables determine the life expectancy of a unit. Among them are: 1. Ambient temperatureTo determine the ambient temperature reading of the air surrounding the unit, readings should be taken around the unit approximately 4 inches away. Gast’s guarantee applies only to units oper-
ating within a temperature range of 32
3
