Butterfly Valve Installation & Butterfly Valve Flow Direction

Attention should be paid to sealing direction before the installation of eccentric butterfly valve. Generally, people are accustomed to installing valves according to the flow direction of the water supply and return pipes, resulting in poor sealing performance of valves with wrong installation direction, which affects the maintenance or accident handling of the pipeline network and equipment.

Pre-Installation Information/Checklist:

Ensure working conditions (pressure and temperature) are within the specified capacity of the product being installed.
Make sure that the construction material of the butterfly valve is chemically compatible with the media flowing in the pipeline.
Inspect the valve’s flange ends and the pipeline’s mating flanges to ensure the surfaces are clean and free of defects. The pipeline should also be checked for proper alignment. API butterfly valves should never be utilized to realign an existing piping system.
The distance between pipe flanges should be checked to assure sufficient clearance for valve installation.
The appropriate material handling equipment should be available to lift larger valves into position.
API butterfly valves are bi-directional and may be installed with flow in either direction, vertically, or horizontally. If a choice of stem position exists, the valve should be installed with the stem in the horizontal position; this will minimize seat wear by distributing the stem and disc weight evenly. Also, if the media is abrasive, the horizontal stem position creates a self-flushing effect that will extend the service life-expectancy of the valve.
Check that the existing pipe sizes match the inlet and outlet sizes of the unit being installed and that no interference exists. If pipeline strain is a concern with larger valves (due to weight), additional support may be necessary.
Since the rubber seat also functions as the seal between the flanges, additional gaskets are not required.
If possible, butterfly valves are recommended to be installed a minimum of six (6) pipe diameters from upstream components, and a minimum of four (4) pipe diameters from downstream components.

Installation Procedure:

Install lever (for manual operated valve) or hand-wheel (for gear operated valve).
Using lever or hand-wheel, turn (clockwise) to ensure valve is in full closed position. Disc should be aligned parallel to the ends.
If disc is not aligned parallel to the ends, for lever style – slightly loosen top plate (by loosening 2 bolts), turn lever clockwise until disc is centered & parallel to ends, and re-tighten top plate. For gear operated valve, adjust hex nuts on side of gearbox. Fully open and close disc several times to assure proper operation. If re-alignment is necessary, repeat.
Proceed with valve installation into piping system. Note that “wafer” style valves are placed between flanges and installed with fully threaded studs, whereas tapped “lug” style valves are installed between flanges with small cap screws on the inlet and the outlet of the valve.
Spread the mating flanges to exceed the valve’s face-to-face dimension by 3/16” before placing the valve into position to prevent distortion and/or damage to the sealing face of the seat.
Ensure that the pipe flange faces are clean of any foreign material such as scale, metal shavings or welding slag.
With disc in the closed position, carefully insert between the flanges, line up, and center. Note that accurate centering between upstream and downstream pipe ends is essential for trouble-free operation of the valves.
While gradually removing the flange spreader and verifying that the valve is centered to the flanges, secure by hand-tightening flange bolts.
Open the valve slowly to the full open position to assure free unobstructed disc movement and that there is no contact with the piping or mating flanges. Note that disc interference may result when valves are installed in pipelines having smaller than normal inside diameters, such as heavy wall pipe, plastic-lined pipe, as-cast flanges or reducing flanges. Interference can also occur when connecting directly to a swing check or silent check. Suitable corrective measures must be taken to remove these obstructions, such as taper boring the pipe, or installing a spacer or spool piece.
After proper operation is verified, flange bolts should then be tightened, using a star or crisscross pattern to evenly load the bolts, to the torque values shown below in table 1.
Pressurize piping to valve and inspect for leakage. If leakage is observed, tighten bolts using cross-over pattern, increasing torque until leak stops. Note that recommended torques are made without warranty. Installer must verify proper strength bolts for applications. Bolts should be clean and un-lubricated.

I. Installation Direction of Butterfly Valve

Since the directional butterfly valves marks the sealing direction on the valve body, the direction of the arrow on the valve body of the two-way sealing butterfly valve refers to the main sealing direction. The arrow direction can also be understood in this way, that is, the arrow points to the drain end. So the supply and return water butterfly valve body arrows all point to the pressure relief end of the usual maintenance, and the eccentric butterfly valve will have better sealing performance with the action of one side medium pressure.

II. Installation Direction of Valve Shaft

All butterfly valves shall be installed in vertical pipes as far as possible, and the valve shaft should not be installed vertically but horizontally for horizontal installation. But the valve shaft can be installed at an inclined angle of no more than 45 degrees if it cannot be installed horizontally, which can minimize the deposition of solids in the fluid at the valve.

III. Other Precautions of Butterfly Valve

Eccentric butterfly valves should generally be installed or welded under the closed state.
The limit of the valve transmission has been adjusted before leaving the factory, so do not remove the transmission at will. If the transmission must be removed, the limit must be readjusted after resumption of installation, and poor adjustment will affect valve leakage and life.
During butterfly valve welding, the grounding wire of the electric welding machine must be lapped on the steel pipe of the welding joint on the same side to prevent the current from passing through the valve body and burning the sealing surface.
When installing the welding valve riser, water with a height of no less than 10mm should be injected above the closed valve plate. And wet cloth should be wrapped on the valve when welding valve is installed horizontally.
Carefully clean the dirt on the eccentric butterfly valve after installation, and carry out 2 to 3 times of complete switching test to check whether the valve can work normally.

Wafer Type Butterfly Valve Installation

The wafer type butterfly valve is one of the most common types of valves in industrial pipelines. The structure of the wafer type butterfly valve itself is relatively small. Just put the butterfly valve in the middle of the flanges at the two ends of the pipeline, and use the double stud bolts to pass through the pipeline flanges and pairs. Clip-on butterfly valves lock the fluid medium in the line. Wafer-type butterfly valves are especially suitable for places where space is limited or where the distance between pipes is short. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very low. Small, so it has better flow control characteristics.

First, the clip-type butterfly valve before installation instructions:

Before the installation starts, remove any foreign matter on the piping with air spray and clean the inner surface of the piping with clean water.
Carefully check whether the valve usage is in line with its performance specifications; (temperature, pressure)
Check the valve channel and the sealing surface for debris, and remove it in time;
After the box is opened, the valve must be installed in time. Do not loosen any fastening screws or nuts on the valve.
Clip type butterfly valve must use a special butterfly valve flange.
Electric butterfly valve can be installed on any angle of the pipeline, for the convenience of maintenance is not recommended to install the inverted.
The butterfly valve flange must be installed to ensure that the flange surface and the sealing rubber center, the screw is tightened evenly, the sealing surface must be complete; if there is uneven screw tightening, there will be rubber protruding stuck disc, or top Live butterfly plate leaks at the stem.

Second, the clip type butterfly valve installation steps:
The correct installation of the wafer type butterfly valve relates to the degree of sealing of the butterfly valve and the possibility of leakage and other issues, including the safety in operating conditions. The user should understand the installation process.

As shown, place the valve between the pre-installed two flanges and note that the bolt holes are aligned.

2. Gently insert the four pairs of bolts and nuts into the flange hole and tighten the nut slightly to correct the flatness of the flange surface;

3. The use of spot welding flange fixed on the pipe;

4. Remove the valve;

5. The flange is completely welded and fixed on the pipe;

6. After the weld is cooled, install the valve. Ensure that the valve has enough space in the flange to prevent the valve from being damaged, and to ensure that the valve plate has a certain degree of opening;

7. Correct the valve position and tighten the four pairs of bolts (be careful not to overtighten);

8. Open the valve to ensure that the valve plate can be opened and closed freely, and then make the valve plate slightly open;

9. Cross-equalization tighten all nuts;

10. Confirm once again that the valve can be opened and closed freely. Note: Make sure that the valve plate does not touch the pipe.

The installation of the wafer type butterfly valve must first be laid flat before installation. Remember that it cannot be bumped freely. After it is pulled into the installed length during installation, it is not possible to design the pipeline in the field without special permission. Feel free to disassemble the clip-on butterfly valve. This is what we need to know before installing. At the same time, we also need to know that the clip-on butterfly valve can be installed in any position, but after the installation of the clip-on butterfly valve, it is necessary to lay the butterfly valve along the line and make a bracket for the clip-on butterfly valve. Once the bracket is made, it is used. It is strictly forbidden to remove the bracket.

Do butterfly valves have a flow direction?

Something went wrong. Wait a moment and try again.

Butterfly type control valve wrongly inserted

bmsg

(Electrical)

(OP)

14 May 10 01:59

A large butterfly type control valve in a fuel-gas line has been installed in the wrong flow direction. Now, it will be difficult to extract the valve from the pipeline and turn it around because structures in the vicinity have to be dismantled first.
However, the pipeline is not yet 'charged' and we will do the job if it is absolutely required.
The butterfly valve is clearance type with 60 degree opening provision(the flow will never be shut completely in the running plant, so minor leakage will not be a problem).
Will you guys let me know whether the control valve will still work as installed now?

RE: Butterfly type control valve wrongly inserted

rneill

(Mechanical)

14 May 10 02:19

What type of butterfly valve is it - for example is it a triple offset type ?

The valve may not have anything like the intended flow characteristic and operating torque values installed backwards if it has an offset disc (likely given the preferred flow direction). I would recommend that at a minimum you consult the manufacturer and obtain their feedback on how it will perform relative to the original specifications (e.g., the data sheet). However, if it were me, I'd fix it.

Note: Operating torque for offset discs as a function of valve position are substantially different based on flow direction to the point where the torque can in fact be acting in a completely different direction. Pressure drop can be different as well but this effect is probably not as significant as the operating torque issue.

RE: Butterfly type control valve wrongly inserted

itascot

(Industrial)

14 May 10 02:56

rneil is right,
call your supplier and ask for torque requirements for valve in its actual direction, if they supplied valve complete with actuator, they can advise if the set-up will fuction correctly. If they advise a torque requirement above that of actuator output, contact actuator manufacturer, they will either advise on (if pneumatic/hydraulic) required pressure changes & possibly spring change (if single acting), as last option, they will give you a different actuator model, but this will make your life difficult regarding testing of complete assembly (valve & actuator).
Ciao,

RE: Butterfly type control valve wrongly inserted

hsbcn

(Mechanical)

14 May 10 13:31

Butterfly valves are generally the most sensitive to flow direction, and you should both check with the manufacturer and also have the plant engineers (yourself?) run a model on how the disc will respond to the new flow direction. Don't forget to share your findings!

My focus: Alloy Valves Duplex Valves Super Duplex Valves Monel Valves Inconel Valves Titanium Valves www.6-moly-valves.com

RE: Butterfly type control valve wrongly inserted

bmsg

(Electrical)

(OP)

15 May 10 02:45

Thank rneill for his reply. Our valve is double-offset type (i.e., offset from centre of the seat and centre of the valve.
We have intimated the problem to the valve manufacturer and are also waiting for their reply.
I will let everybody know what the manufacturer says.

RE: Butterfly type control valve wrongly inserted

NGiLuzzu

(Mechanical)

19 May 10 06:44

bmsg,
     I'm afraid I didn't understand the situation properly: is the valve working between 60° and 90° opening or between 0° and 60°?

     May be they will tell you that, if you want the same flow rate, you have to slightly change (probably increase a little) your 60° angle, I guess...
     I believe that Cv values and flow characteristics do not change dramatically between the two possible directions (when a "preferred direction" is mentioned, this is referred to seat tightness more than to flow...).

Best Regards,
             'NGL

RE: Butterfly type control valve wrongly inserted

gerhardl

(Mechanical)

19 May 10 14:31
Further to anegri's posting, I also have to ask for clarification of this point.

Anyway:

1. You will either have some special constructed regulating composed disc, cage type or similar, to give support for a complicated and large pressure flow and drop.

If this is the case the answer to your question is more complicated and could be negative.

2. Or you will have,if you are at the other end of the scale, a controlled, slow and laminar flow, and a disc with more of a common flat and compact form. This type of valve is normally used as a typical on/off valve, but in this case used to regulate.

If this form is what you have, the answer is a bit simpler and could be positive.

The reason for this is that if you look at this case with incompressible fluids (water) a double offset (double eccentric ) valve will only be properly regulating as long as you have a full pipeline, a low pressure drop, and maintain the flow with a delta p over the valve low enough not to give cavitation.

In addition to this it is commonly known that regulating will only be possible when the valve is at about 20 degrees of opening or less. In addition the regulating will be more coarse than for a proper regulating valve.

If the fluid is gaseous the operation is similar.

If this latter example is relevant, the regulating result could well be within acceptable accuracy with a flow in the 'non preferred direction, - the valve is usually both constructed (and could also be presuure tested) for this.

The problem could more be that 'the wrong direction' is perhaps not tested out for regulating purposes: -flat face against the flow and stem and stem bearings behind in stead of opposite, and it could be difficult or costly to establish flow curves and get the factory to give sufficient back-up and guarantee for the result and problem free (cavitation free) operation if regulating this way.

Further to anegri's posting, I also have to ask for clarification of this point.Anyway:1. You will either have some special constructed regulating composed disc, cage type or similar, to give support for a complicated and large pressure flow and drop.If this is the case the answer to your question is more complicated and could be negative.2. Or you will have,if you are at the other end of the scale, a controlled, slow and laminar flow, and a disc with more of a common flat and compact form. This type of valve is normally used as a typical on/off valve, but in this case used to regulate.If this form is what you have, the answer is a bit simpler and could be positive.The reason for this is that if you look at this case with incompressible fluids (water) a double offset (double eccentric ) valve will only be properly regulating as long as you have a full pipeline, a low pressure drop, and maintain the flow with a delta p over the valve low enough not to give cavitation.In addition to this it is commonly known that regulating will only be possible when the valve is at about 20 degrees of opening or less. In addition the regulating will be more coarse than for a proper regulating valve.If the fluid is gaseous the operation is similar.If this latter example is relevant, the regulating result could well be within acceptable accuracy with a flow in the 'non preferred direction, - the valve is usually both constructed (and could also be presuure tested) for this.The problem could more be that 'the wrong direction' is perhaps not tested out for regulating purposes: -flat face against the flow and stem and stem bearings behind in stead of opposite, and it could be difficult or costly to establish flow curves and get the factory to give sufficient back-up and guarantee for the result and problem free (cavitation free) operation if regulating this way.

RE: Butterfly type control valve wrongly inserted

JLSeagull

(Electrical)

23 May 10 14:54

Nearly three decades ago, a commonly recommended shutdown valve installation for the inlet of a turbo-expander-compressor was a butterfly valve intentionally installed backwards. I don't remember the advantage.

RE: Butterfly type control valve wrongly inserted

gerhardl

(Mechanical)

23 May 10 18:13
J.L.Seagull: backlash presuure peak in opposite (e.g. preferred) direction?

J.L.Seagull: backlash presuure peak in opposite (e.g. preferred) direction?

RE: Butterfly type control valve wrongly inserted

Scotsinst

(Petroleum)

26 May 10 00:10

JL Seagull: we install the downstream triple offset butterfly valve in a DB&B installation backwards for isolation if downstream will be pressurized.
They are bi-directional with a preferred pressure direction and the actuator thrust requirement is less for shutoff in the preferred direction.

RE: Butterfly type control valve wrongly inserted

itascot

(Industrial)

26 May 10 11:37

Be aware that a offset butterfly valve in preferred direction has a BTO (break to open) torque higher than TSO torque, the opposite applies when offset valve is in non-preferred direction (higher to seat/seal & lower to unseat/open).
Ciao,

RE: Butterfly type control valve wrongly inserted

mechphani

(Mechanical)

7 Jun 10 22:03

hi,
Most of the manufacturers design High performance butterfly valve with bi-directional capability.depending upon manufacturer using the valve in reverse may reduce lifetime.

if you get the hydrotest report from manufacturer,check the report and see if the unit was tested bi-directional in compliance with API 598 to ensure a bubble tight seal.then you dont have any major problem using it in present installed conditions.

if it is dead end service you have to double check with manufacturer regarding pressure temperature capability, but as per your statement,it is not for dead end service also.

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