Yokota develops Dashpot Type Non-Water Hammer Check Valve
|Featured in The Nikkan Kogyo Shimbun newspaper issued on Friday, Jul. 4,
Yokota Manufacturing Co.
Equipped with hydraulic pressure buffering device
Check valve with buffered closing by-pass valve
[Hiroshima] Yokota Manufacturing Co. (1-3-6 Minami Yoshijima, Naka-ku,
Hiroshima, President: Hiroshi Yokota, Tel: 082-241-8672) has developed
and released a buffered closing by-pass type check valve (photo) with a
hydraulic pressure buffering device (dashpot) for sewer and water supply
piping systems. The pricing is from 596,000 yen for the 150mm bore to 13,300,000
yen for the 1,000mm bore.
The check valve prevents counter flow. The non-water hammer type valve
prevents shock when counter flow stops instantaneously and pressure increases
rapidly, however, the water flow to the by-pass can be controlled slowly
via hydraulic pressure due to the built-in dashpot.
The product is characterized by its wide application from low to high pump
heads. The dashpot is installed beside the valve case for easy adjustment
and maintenance, also, oil control is unnecessary because there is no sealing
area on the liquid contact surface.
Copyright for this article is with The Nikkan Kogyo Shimbun
|Featured in The Nihon Keizai Shimbun (Nikkei) newspaper issued on Wednesday,
Jun. 25, 1997
Featured in news articles as, "Yokota develops check valves with counter
flow control device for pumps".
|Featured in FujiSankei Business-i newspaper issued on Monday, Jun. 23,
Non-Water Hammer Check Valve
Yokota Manufacturing Co. developed (Hiroshima)
Yokota Manufacturing Co., a specialized manufacturer of pumps and valves
(President: Hiroshi Yokota, Hiroshima Tel: 082-241-8672), developed and
began sales of a "slow-closure by-pass type check valve equipped with
a dashpot". The product integrated a compact dashpot in the non-water
hammer check valve which opens and closes according to water volume, and
is used at water supply and sewer facilities.
The distinguishing feature of this new product is the prevention of water
hammer and shock due to the quick and complete closure of a main valve
at the moment water flow in a pipe is reversed from positive flow (the
point at which water stops in a pipe), as well as the prevention of pressure
build-up after the main valve closes, using the slow-closure by-pass valve.
As a result, the product has wide application from low to high pump heads,
with ease of use and maintenance.
The main valve is a single-disk of extremely simple construction (built-in
counterweight), with added cost reductions possible through compact designing.
Moreover, the compact dashpot requires no oil maintenance because there
is no seal on the liquid contact side, and thus no oil leakage. The pump
can be installed on either vertical or horizontal piping.
Yokota produces a series of valves ranging from a minimum bore of 150mm
to the 1000mm large-size bore (Valves manufactured with bores of over 1500mm
are also possible), with a manufacturing target of 500 units per year.
Pricing on the 150mm-bore valves is 596,000 yen, and 13,300,000 yen for
|Reprinted from the FujiSankei Business-i newspaper, Jun. 23, 1997 issue
For details of this product, please refer to
Dashpot Type Non-Water Hammer Check Valve SL-SN-B, SL-SH-B types.