Frequently Asked Questions
We have summarized the questions that you often inquire about.Please refer to it before you inquire.
See “Trouble Shooting” for information on problems.
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- Does a gate valve have a flow direction?
There is no restriction on the flow direction of a gate valve.
However, note that the flow direction of fluid is restricted when a vent hole is provided.
- Is it possible to install a valve with the top and bottom upside down?
Regarding the piping posture of the valve, it is not recommended to tilt the operating device (handle, gear operating device, pneumatic operating device, electric operating device, etc.) below the horizontal line. When the valve is tilted below the horizontal, foreign matter may accumulate in the gland part due to the effect of gravity. When the valve is opened and closed in this state, foreign matter may enter the packing due to the rotation of the stem, wear the packing and cause gland leakage. Therefore, please arrange the piping so that the operating device is above the horizontal as shown below.
Please refer to the FAQs below for restrictions on the piping posture and flow direction depending on the valve type.
・Is it possible to use a swing type check valve in vertical piping?
・Is it possible to use a lift type check valve in vertical piping?
・Is there any restrictions on the installation posture of a wafer type check valve?
・Is it possible to use a vertical lift type check valve horizontally?
・Tell me about the piping posture of a Y-strainer.
- Do you have a gate valve that can be used for flow rate regulation of fluid?
We do not recommend using a gate valve for flow rate regulation.When a gate valve is used for flow rate regulation (intermediate opening), the disc may continue to hit against the seat, resulting in seat wear and seat leakage.
We recommend a globe valve for flow rate regulation.
- Does a globe valve have a flow direction?
A globe valve has a predetermined flow direction of fluid.
Please check the arrow of the casted display on the valve body.
- Is it possible to use a swing type check valve in vertical piping.
It is possible to use a swing type check valve in horizontal piping and vertical piping.
However, when installing in vertical piping, make sure that the fluid flow direction in the piping is from the bottom to the top and that the arrow of the casted display on the valve body is from the bottom to the top.
- Is it possible to use a lift type check valve in vertical piping.
It is not possible to use a lift type check valve in vertical piping.
A lift type check valve can be used by installing it in horizontal piping only.
When installing the valve, be sure to install it with the cover facing the top.
- Is there any restrictions on the installation posture of a wafer type check valve.
A wafer type check valve has restrictions on the fluid flow direction and valve installation direction.
When installing the valve, pay attention to the following points and install it so that the direction of the arrow on the valve body matches the fluid flow direction.
・ Although the valve can be used in vertical piping, make sure that the fluid flow direction in the piping is from the bottom to the top and that the arrow on the valve body is also from the bottom to the top.
・When connecting a dual plate type (two disc type) product to horizontal piping, install it so that the bypass valve is positioned in a horizontal position.
・In the case of a single plate type (one disc type) product, install it so that the pin is positioned in the upper position. If it is installed at an angle other than horizontal, the disc may not fully close due to the influence of gravity.
- When a pump is installed upstream of a check valve, what distance is required from the pump?
① Swing type, lift type, ball type check valves
Chattering may occur because of turbulence, eddy currents, or pulsation of the fluid.
Install the valve with a distance of at least six times the pipe nominal diameter.
② Wafer type check valves (excluding stainless steel products)
As for pump discharge, the valve can be directly connected to the pump.
③ Stainless steel wafer type check valves
Since the structure is different from wafer type check valves made of other materials, the valve cannot be used by connecting it directly to the pump.
As for pump discharge, ensure a straight pipe section that is at least twice the pipe nominal diameter (at least three times the bore diameter when the pump discharge has a tube expansion of two sizes or more).
- Are there regulations for the seat leakage amounts of bronze/brass check valves?
When taking a 10K bronze/brass valve as an example, based on JIS B 2003, the seat leakage is measured by applying water pressure at 1.54 MPa (1.1 times) and then reducing the pressure to 0.51 MPa, which is 1/3 of the initial pressure.
Judgment of test result: 0.1 (mm3/sec) x Valve nominal diameter (mm)
For example, in the case of 50A, the test time is 15 seconds and the leakage amount is 0.1 x 50 = 5 (mm3/sec) and 5 x 0.06 = 0.3 (mL/min).
- A check valve has a seat leakage, is there a regulation for the leakage amount?
At the time of shipment, the leakage amount is less than the specified amount. However, after use, the valve body wears because of the opening and closing, and the leakage amount increases compared to that of the shipping inspection. Since it is difficult to seal with a check valve, please install a valve such as a gate valve for sealing.
- Is it possible to use a ball valve with a half-open state?
Do not use a ball valve with a half-open state. The seat will be damaged, causing leakage.
(However, ball valves for flow rate regulation are excluded.)
- Is it possible to fully close a three-way ball valve in addition to switching the flow paths?
We have no product that can be fully closed with a three-way ball valve.
Please check the switching form in our product catalog, etc.
(Ball Valve General Catalog)
- Tell me how to use the rating. For example, a product called Eco Ball Z, which can be used up to 4.12 MPa up to 38°C and up to 0.98 MPa up to 150°C, can be used up to what MPa when used at 100°C?
It can be calculated by the proportional interpolation method.
0.98 + (4.12 – 0.98) x (150-100) / (150 – 38) = About 2.38 MPa
The calculation method is described in the catalog, so please refer to it.
In addition, an automatic calculation formula can also be used from our website.
Please check the rating of each product in the catalog before using it.
- Is it possible to connect stainless steel piping to an aluminum butterfly valve?
An aluminum butterfly valve can be used with stainless steel piping.
The parts that come into contact with the fluid are only the disc and the rubber seat, but the disc does not come into contact with the piping and the rubber seat that comes into contact with the piping does not conduct electricity. Therefore, dissimilar metal corrosion does not occur.
- When installing a butterfly valve, what length of bolts / nuts for piping should be used?
The required dimensions of hexagon bolts / nuts for piping of butterfly valves are introduced in the catalog. Please refer to it. In addition, the bolts / nuts for piping are not attached to the product.
(General Catalog, Digest Version / Butterfly Valve General Catalog)
- Tell me about the piping posture of a Y-strainer.
Install a Y-strainer so that the screen faces downward.
・In the case of horizontal piping, connect the piping so that the cap or cover faces downward as shown in the figure.
・When the fluid is descending in vertical piping, connect the piping so that the cap or cover faces downward as shown in the figure. When the fluid is ascending, provide a horizontal piping section to connect the piping.
If the strainer is installed in the reverse position, foreign matter and dust may flow back into the primary piping, so it is not recommended.
- When installing a butterfly valve, are gaskets for piping necessary?
For the product whose seat material is rubber (seat rubber), the rubber seat (seat rubber) also plays the role of piping gaskets. Therefore, piping gaskets are not required.
For the product whose seat material is not rubber (seat rubber), piping gaskets are required. Since the types / dimensions of gaskets that can be used may be limited, please refer to the instruction manual / catalog of the product.
(Butterfly Valve General Catalog)
- Regarding cleaning of the screen of a strainer, what is the recommended frequency?
We recommend cleaning the screen when the differential pressure across the strainer approaches 0.1 MPa.
- Tell me the characteristics of a U-strainer.
A U-strainer is easy to clean because the screen is removed from above after removing the top cover. Therefore, it can be used in lines where maintenance space is not available with a Y-strainer in floor piping.
However, please note that the installation posture is only for horizontal piping.
- Do you sell the screen of a strainer as a separate part?
We sell it as a maintenance part.
Please contact your dealer for the product model, nominal diameter and screen specifications.
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