Mucon iris diaphragm flow control valves

Ideal for “trickle-feed” applications

Mucon Iris Diaphragm Valve (IDV) utilizes a concentrically closing fabric or rubber diaphragm to accurately control the flow of powders and granular material.

Ideal for “trickle-feed” applications and shutting off against a flow of material.


  • No jamming (no mechanical components in contact with product)
  • Full bore opening (no restriction to product flow).
  • Trickle feed capability
  • Hand, pneumatic or motorized options
  • Slim design – low install height
  • No mechanical wear by abrasive products
  • Dust tight – no leakage to atmosphere
  • Ability to seal around irregular objects
  • Suitable for delicate products
  • Hygienic designs available
  • Easy to maintain and operate
Diaphragm type FabricCoated fabricRubber
  • Terylene is abrasion resistant

++ Viton Coated Terylene is ok for 200ºC.

Select most appropriate material using the diaphragm selection guide.

Diaphragm selection guide

Application Food quality white rubberRed rubberAnti-static rubberMock lenoNylonAnti-static nylonHypalon coated nylonPoly-urethane coated nylonTeflonTeryleneVitron coated terylene
Powder below 150 mesh (104 microns)••••••••••••••
Granules over 150 mesh
SlurryUnder 1M headerUnder 1M headerUnder 1M header
LiquidUnder 1M header Under 1M header Under 1M header 
Air or gas
Abrasion resistance••••••
Max Temperature70ºC70ºC70ºC70ºC110ºC110ºC120ºC100ºC250ºC130ºC 200ºC
Min Temperature-40ºC-40ºC-40ºC -40ºC -75ºC-75ºC-35ºC -40ºC-75ºC-75ºC-40ºC 
Pressure or vacuumBelow 0.14 barUp to 0.20 bar
Food or pharm•• •• 
Infestation or mold growth •• ••  
Dangerous static
Hygroscopic •• •• •
Oil or fat content •••
Poor flow••••••
 FlammabilityInflammableInflammableInflammablenflammableWill not propagate a flameInflammable
Weather resistanceGoodExcellentGoodVery GoodSlow loss of strengthExcellentExcellentExcellentSlow loss of strengthGood
Tensile strength kgs/cm²1201201205.6254.625% above base material25% above base material4.66.4006.400
Elongation & break700%700%700%25%25%25%25%13%30%30%
Cost factor 1-lowest 5-highest22511111515
Availability 1-best 5-worst11531431424
Application ADADPEHJSKDisc*
IBC’s – Discharge to atmosphereYesYes
           – Mating connectionYesYesYesYesYes
FIBC’s – Throttle neckYesYesYesYes
Other applications ADADPEHJSKDisc*
Isolation onlyYes
Flow controlYesYesYesYesYesYes
Open / close – frequentYesYesYesYes
                        – infrequentYesYes
High BD (1600 kg/m³+)YesYesYesYes
Pressure / vacuum (up to 3 bar)*Yes
 High temperature (250ºC+)Yes
Hygienic / easy to cleanYes

The diagram shows the ideal way in which a Mucon Iris Diaphragm Valve should be installed. If the recommendations are followed, a prolonged diaphragm life will result. The AD, JS & K series of valves have lever slots, which allow the control levers to move through 180°. Accordingly, installation requires a combination of through bolts and set screws to be used. If there is any misalignment of the ductwork connected to the valve, this can cause the lever slot to open or close. With a serious misalignment, the valve body will be under stress, which could lead to rapid wear taking place and the failure of certain components. All valves are fitted with a label indicating the directions of material flow.

  1. Flanges must be flat and free from distortion.
  2. Fixing bolt over and under lever slot must not protrude into the slot.
  3. For diaphragm length see inside brochure.
  4. 12mm clearance from base of open diaphragm.
  5. Inlet diaphragm 5mm smaller than inlet size of valve.
  6. Discharge diameter 10mm larger than outlet size of valve.

The use of a liner with a Mucon Iris Diaphragm Valve installation may enhance the operation and capability of the valve typically by –

  1. Acting as a hygienic and protective liner.
  2. Assisting diaphragm opening.
  3. Combating diaphragm wear.

Liners can be used on their own or with an adaptor.

1) Use As A Hygienic or Protective Liner
By inserting a liner through the diaphragm of the Mucon Iris Valve, you can isolate the valve components such as the body, clamp ring and diaphragm from the flow of potentially harmful or dangerous powders.

Typical Applications include:

  1. Lining the iris valve with a liner produces smooth powder contact surfaces resulting in a more hygienic and easier to clean assembly. This arrangement is especially good in Food, Pharmaceutical and other applications where powder hold-up is not desired.
  2. Lining of the iris valve to protect the valve components from potentially harmful and corrosive powders.

2) Liners to Assist Diaphragm Opening

Where a fabric diaphragm is specified, it is always necessary to have a certain weight of material acting downwards to make it open fully. If the material has a tendency to bridge, often the diaphragm will only partially open.

If a flanged liner is hung through the valve (1) with weights of stainless steel sewn in the hem of the liner (2), this will assist in opening. (See illustration)

Liners also reduce the effort required to operate valves

Various powdered materials exert differing pressures on a diaphragm. Normally a Mucon Iris Diaphragm Valve is easily operated, but on occasions some free flowing products exert a high static load on a valve and the control lever becomes difficult to operate. This is due largely to two things:

  1. The load exerted by the product forces the various layers of diaphragm material tightly together and when the control lever is operated, these try to rotate against each other.
  2. It has been observed that when a Mucon Iris Diaphragm Valve operates, the material in the column adjacent to the top face of the valve tries to turn as the valve is opened.

Both of these problems can be eliminated by the use of a liner.

3) Liners to Combat Diaphragm Wear
The length of life of a diaphragm is not easily quantified because of the many variables involved such as:

  1. Number of operations per day.
  2. Amount of material passed per day.
  3. The abrasiveness of the material.

In our experience the life of a diaphragm can vary between a few months and many years. Where the life can be measured in months it is often beneficial to consider the use of a liner.

The most frequently used liner material for combating abrasion is LINATEX rubber. This is a natural rubber with a better resistance to abrasion than steel. Where this is used it is important that a fabric diaphragm is used in the valve.

For in-line applications a double flange liner can be used.

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