They are compact, simple in construction, and do not require inlet and outlet check valves.
Since screw pumps do not need inlet and outlet check valves, they can be used to pump very viscous liquids.
George Atallah, the association's assistant executive director, said, "My message is, regardless of the outlet, check with the association to get a sense for its previous coverage".
Vane pumps do not need inlet and outlet check valves; they can pump liquids containing vapours or gases but are not suitable for pumping liquids containing solid particles.
Mr. McClain said he spent two days this week walking through an S & S retail outlet, checking tire pressure on customers' Ford Explorers.
The program (which is being offered to other public television outlets; check local listings) is also sprinkled with fellow comics who talk about the art of the 2,000-year-old 2,000-year-old 2,000-year-old
The "American Masters" programs on PBS are almost always rewarding, but the episode about Cab Calloway on Sunday night on Channel 13 in New York (and on Monday night on many other PBS outlets; check local listings) is unusually so, with smart, well-presented insights into his music, his dancing, his acting and his barrier-crossing appeal.
One good way to locate air leaks inside, Ms. Johnson said, is to hold a lighted candle around the frames of windows, doors and electrical outlets, checking to see if the flame quivers.
"I've got twenty outlets to check, and I check them three, four times a day.
Beforehand he sits in a nearby Del Taco fast-food outlet and checks his BlackBerry, which suddenly offers good news.
Figure 1 Simplified process flow diagram for catalytic conversion of H2S to elemental sulfur (1, H2S cylinder; 2, O2cylinder; 3, bomb; 4, gas inlet; 5, absorber/regenerator; 6, outlet gas checking port; 7, sulfur recovery; 8, gas inlet; 9, NaOH scrubber; 10, sweet gases; V1 V9, valves).
