2011 8th Cho Monodzukuri Grand Award for Parts: Incentive Award Awarded Product
2011 "Cho Monodzukuri Grand Award for Parts"
High Performance Sanitary Soft Diaphragm Valves
Recommendation： Osaka University, Honorary Professor Kotohiko Sekoguchi
In the Cho Monodzukuri Grand Award for Parts organized by The Monodzukuri Nippon Conference and Nikkan Kogyo Shimbun, held on December 6th 2011, Fujikin's "High Performance Sanitary Soft Diaphragm Valves" was honored with the Incentive Award. We would like to express our sincere gratitude to Professor Kotohiko Sekoguchi of Osaka University who gave the recommendation for this product and also to everyone for their warm support.
Although the market for the parmaceutical industry has recently been constantly growing, it is expected to continue to grow in the future. From the recent reports that the new bird flu pandemic will rage in the near future, the international society's interest in the pharmaceutical industry is rising, and further large-scale initiatives such as countermeasures against viruses by civilian and administrative measures and measures against other threats are going to be made not only in Japan but throughout the world.
On the other hand, product quality requirements made by the international society for the pharmaceuticals manufacturing process grow everyday, and a lot of effort is taken to maintain a constant standard product quality. Part of that can be inferred from detailed description in the US Good Manufacturing Practice (GMP) which is the Pharmaceutical Quality Management Regulation in the United States.
If a quality problem arises the loss easily reaches the order of tens of millions of yen. From the point of view in maintaining a sound business, the most important thing is to establish manufacturing technology that has high reliability and stability.
Similar to the above market trends and product quality requirements in the pharmaceuticals industry, manufacturing departments in the food industry also strongly desire an upgrade in technology.
For better operation of these manufacturing processes, further progress is required in the design and manufacture of diaphragm valves that play an important role as a key tool. Fujikin has developed the high performance sanitary soft diaphragm valve in order to meet the requirements of the aforementioned pharmaceuticals and food industries, and we have concentrated on new devices that contribute to improving reliability.
The main points of the new devices are that the diaphragm is composed of a resin diaphragm and rubber backup, in which the resin diaphragm can keep the external seal by itself, whereas in the past the rubber backup could not keep the seal.
In order to avoid the shape of the membrane collapsing due to repeated opening and closing of the valve, the rubber backup is made thin while increasing hardness. By removing concerns of the shape of the rubber collapsing, the valve maintains high reproducibility over a long period at the initial flow rate characteristics of use of the valve. From the point of view of product quality management for the manufactured products, it holds an extremely important meaning and is rated highly.
In particular, this design is characterized by the diaphragm which plays a role in the stoppage of the established flow, and the annular protuberance on the outside helps guide the relative correct position for the valve body and bonnet. This annular protuberance is an integral feature adopted by the diaphragm (construction patent). In particular, this characteristic is characterized by adopting a diaphragm having a complex function.
By applying the sealing function to the annular protrusion, compared to the case where the seal is made of a smooth surface, the reliabilty of the sealing function is greatly improved, and reducces fatal faults in the production line when there is an emergency shutdown or bad product batch.
Furthermore, by adopting a system in which the annular protrusion is responsible for the sealing function, it is possible to considerably reduce the amount of residual fluid that accumulates in the gap where the diaphragm and valve join.
In short, the features of this new diaphragm is that it clearly defines the roles of these two resin and rubber diaphragms, and is designed to show the effectiveness of these diaphragm's functions.
With this unique technology, it contributes to the improvement of reliability and stability in manufacturing processes for pharmaceuticals and other similar industries, and is highly rated.
Subsequently, the development of the sanitary soft diaphragm valve with these components can be said to reinforce business operations to conform with the country's policies and influenza countermeasures.
It is believed that the high performance sanitary soft diaphragm valve will play a big role in developing the pharmaceuticals industry in Japan, and was recommended for the 2011 Cho Monodzukuri Grand Award for Parts.
These diaphragm valves are used for process lines for pharmaceuticals and food products.
Our company has been manufacturing and selling sanitary soft diaphragm valves for pharmaceuticals and food products from the past. In order to respond to the recent sophistication of demands of users in recent years, we developed a new series of products to fix the existing product's issues, such as reducing the vulnerability of the external seal performance, reducing flow rate fluctuation from the first time due to valve opening/closing and age, and also minimizing fluid accumulation.
Compared with conventional products, the external seal performance is retained for more than 10 times longer, and the rate of flow rate fluctuation is less than 1/30 of the conventional products.
Also, the diaphragm material for the wetted side uses modified PTFE for excellent flex resistance, and the backup rubber for the semi-wetted part uses EPDM for excellent steam resistance. Both of these conform to the FDA (American Food and Drug Administration) and USP (United States Pharmacopeia) Class VI classifications.
Conventional products keep sealing performance by pushing the protuberances on the outer circumference of a two layer PTFE/rubber diaphragm in with upper and lower flanges.
With this, ① By inserting rubber that is susceptible to deformation and expansion / contraction due to temperature cycles and aging, the tension on the clamp is softened. This causes the surface pressure of the seal to lower and external leaks occur.
② Due to the opening and closing of the valve, the radial direction of the valve is deformed, and the seal protuberances on the outer circumference slide and wear down. This lowers the sealing performance and causes external leaks.
As a countermeasure to ①, this valve only has PTFE inserted instead of the rubber which is now confined to the inner gap. This prevents reduction in surface pressure and sealing performance is improved.
Also as a countermeasure to ②, on the outer edge of the seal protrusion of the diaphragm outer circumference, new fixing protrusion (guides) are provided, which insert into the grooves of the body and bonnet. This suppresses the radial direction deformation of the diaphragm and prevents abrasion of the seal protrusion on the outer circumference.
Conventional products used soft (low hardness) materials for the backup rubber.
This is because the backup rubber diaphragm is thick and the load during bending is large, which requires a highly flexible rubber material. By increasing the flexibility of the rubber, the backup rubber becomes largely deformed due to the opening and closing the valve, and this deformation process also causes the PTFE of the wetted side to become deformed. This narrows the flow path and results in a change of the flow characteristics.
By using a thinner rubber diaphragm for this valve, the flexibility is kept while increasing the hardness of the backup rubber, which prevents deformation of the backup rubber and reduces the change in flow characteristics.
With conventional products, it is difficult to match the position of the diaphragm and body when assembling them together, and in order to maintain external sealing performance even when there is a shift in position, a wide flat contact surface on the body is required for the seal protrusion on the outer circumference of the diaphragm.
As a result of this, the gap between the diaphragm's outer seal protrusion and the body's flat surface is large, which allows fluids to accumulate in this section and the valve's internal fluid displacement characteristics are lowered.
This valve uses protrusion on the outer circumference of the diaphragm for fixing the body and diaphragm which stops it shifting out of position. This minimizes the flat surface area of the body and reduces the lowering of the fluid displacement characteristic due to accumulated fluids.
Regarding the sealing performance, our company performed durability tests, and for the conventional products, leaks occured after the valve was opened/closed ten thousand times. Compared to conventional products, this valve did not occur any leaks even after being opened and closed one hundred thousand times.
For the change in flow characteristics, the flow rate after the open/close test is compared to the initial flow rate. The open/close durability test is done in high temperature vacuum conditions, and with the conventional products, the flow rate from initial use falls by 30%, whereas this valve falls by less than 1%.
Also, accordingly to item（1.3）, by minimizing the space for fluid accumulation, the valve's fluid displacement performance was improved.
Diagram 1. Diaphragm construction compared with conventional products
Diagram 2. Body construction compared with conventional products
By adopting this valve, ① external seal performance is largely improved, which prevents the risk of external leaks and stops outside air coming into the piping under vacuum conditions.
With this, the user's maintenance cycle is extended and the primary cause of non-compliance by product contamination is removed.
② By reducing the amount of change in the flow characteristics, users who are using it as a filling valve are not required to make frequent adjustments to conditions such as filling time and pressure, which shortens operation time.
③ By minimizing accumulation of fluids and improving fluid displacement performance, it makes it possible to do clean-in-place (CIP) and sterilization-in-place (SIP). The risk of contamination by fluid residue is reduced and the cause product non-conformity is removed.
With the above, it became possible to improve the user's production efficiency and lower running costs.
Currently, we have shipped more than 4000 units.
From now, the sanitary soft diaphragm valve is a mainline product that focuses on replacing existing products and we aim to sell 30,000 in a year.
By improving the functionality of the external seal, minimizing the space for fluid accumulation, and the risk of contaminating products such as pharmaceuticals and food in the manufacturing process is reduced.
The diaphragm material conforms to the FDA (American Food and Drug Administration) and USP (United States Pharmacopeia) Class VI classifications.