초록 ▼

A double check valve reduced pressure backflow preventor assembly is configured to have a relatively small length, volume and/or weight. The assembly defines parallel, preferably coaxial, inlet and outlet directions. In one aspect, first and second check valves are at an angle, preferably of 90°, to

A double check valve reduced pressure backflow preventor assembly is configured to have a relatively small length, volume and/or weight. The assembly defines parallel, preferably coaxial, inlet and outlet directions. In one aspect, first and second check valves are at an angle, preferably of 90°, to the in-line axis and preferably intersect the in-line axis. In one aspect, a relief valve is positioned spaced from the in-line axis. First and second shutoff valves are enclosed in the same integral, unitary housing which encloses the check valves and, preferably, some or all of the relief valve. The shutoff valves are preferably positioned along the in-line axis.

대표청구항 ▼

A double check valve reduced pressure backflow preventor assembly is configured to have a relatively small length, volume and/or weight. The assembly defines parallel, preferably coaxial, inlet and outlet directions. In one aspect, first and second check valves are at an angle, preferably of 90°, to

A double check valve reduced pressure backflow preventor assembly is configured to have a relatively small length, volume and/or weight. The assembly defines parallel, preferably coaxial, inlet and outlet directions. In one aspect, first and second check valves are at an angle, preferably of 90°, to the in-line axis and preferably intersect the in-line axis. In one aspect, a relief valve is positioned spaced from the in-line axis. First and second shutoff valves are enclosed in the same integral, unitary housing which encloses the check valves and, preferably, some or all of the relief valve. The shutoff valves are preferably positioned along the in-line axis. tain a second frequency; applying the club head to the club shaft; and rating the golf club based on a sum of the first and second measured frequencies. 4. A method for evaluating performance characteristics of a golf club having a club shaft and a club head, comprising the steps of: fixing a rear end portion of the club shaft; vibrating a tip portion of the club shaft while the rear end portion of the club shaft is fixed; measuring frequency per unit time of the vibrating shaft to obtain a first frequency; fixing the tip portion of the club shaft; vibrating the rear end portion of the club shaft while the tip portion is fixed; measuring frequency per unit time of the vibrating shaft to obtain a second frequency; applying the club head to the club shaft; and rating the golf club based on a ratio of the first and second measured frequencies. 5. The evaluation method for a golf club according to any one of claims 2 to 4, including a step of attaching a weight to the tip and rear end portions before vibration thereof, respectively. 6. The evaluation method for a golf club according to any one of claims 2 to 4, wherein said club shaft is made of fiber reinforced resin.