Diaphragm valve and bellows valves comparison
Aseptic producing process, the most commonly used globe valve is diaphragm-type globe valve, usually referred to as diaphragm valves. The reason why using diaphragm valves in aseptic producing process, first is because of its simple structure, second, the price is cheap, which makes it so far almost without "competitor." The only one that can compete with the diaphragm valves is the so-called bellows globe valve, that is commonly referred to as bellows valves. This bellows globe valve because its price is too high, despite a better technology advantage than the diaphragm valves, but it is still very difficult to compete with diaphragm valves, such as described in this article.
PTFE bellows
In the aseptic process industrial field, " the competition between bellows valve and diaphragm valves," has been existing for a long time. For a long time, diaphragm with its simple structure, inexpensive, and cleaning and disinfecting convenience takes an advantage. Compared with the diaphragm valves, bellows valves have too few varieties and specifications in the market. Today, Tuchenhagen produced Vesta bellows valve is filled this gap, this paper makes a clearer understanding of the advantages and disadvantages of the two kinds of valves through the comparsion between diaphragm valves and bellows valves.
Empty Properties
When you need to use the diaphragm valves in horizontal pipes, it must ensure that installing diaphragm valves in horizontal pipes in accordance with the specified angle of diaphragm valves manufacturers, or in the process equipment operation, diaphragm valve empty will encounter some problems, can not completely discharge media in body. However, different types of diaphragm valves, different manufacturers of diaphragm valves, the installation of tilt angle of different nominal flow diaphragm valves is different, which will often bring a lot of trouble to the design and manufacture of aseptic process equipment. In the T-type structure diaphragm valves, clearing body problem is more obvious. Compared with the diaphragm valves, Vesta bellows valve does not have such problem, regardless of Vesta bellows valve body is what kind structural form, it will not occur a "dead"in the process equipment no-load running, so ensures strictly to cut off pipeline. Moreover, it can be installed in piping system of aspetic process equipment according to different installing modes. In the pharmaceutical manufacturing, aseptic process equipment is composed by a number of horizontal pipes and vertical pipes, in the design of pharmaceutical equipment, because of the pipeline location and technical aspects, must install this bellows valves in a specific location. For example, if installing diaphragm valves in vertical pipes, must through an 90°elbow connection in the same horizontal plat. The T-structural diaphragm valve producting cost is too high, compared with different body structural shape diaphragm valves, bellows valves have better advantages in connecting and installing with pipes in size and appearance. Because the two globe valve structural types are different, so in the early stages of aseptic process equipment design, you should make a good choice of every part should be selected which kinds of globe valves. The output device in medicine, food and biotechnology field has a large number of valves required to be sterilized. While the large valves, for example, Stericom series, in which situations required to be sterilized is almost useless. Because in this process equipment, the media quality that required to delivery is less and less, for less flows, it is almost invariably chose the diaphragm valves. The new bellows valve has a smaller size, can be equipped with different pipe diameters, in this side, it is more competitive than diaphragm valves.
Comparison of equipment utilization
As a device user, you should use the equipment to produce as much as possible in the entire life cycle, that is: the utilization of equipment should be as high as possible. While maintenance of the equipment means the equipment must have to stop production, and also need to invest certain amount of equipment maintenance costs. Bellows valves generally have wear and tear; in diaphragm valves, the valve once occurs wear and tear, you should replace diaphragm after a certain amount of time, diaphragm service life depends on the corresponding producting process. On the one hand, process equipment flow media corrosion, pipeline cleaning and disinfecting temperature, process equipment working pressure and flow, and other operating parameters will affect the diaphragm life; the other hand, when opening and closing diaphragm globe valve, the disphragm deformation is also the important factors of deciding diaphragm service life.
Vesta bellows globe valve With pneumatic drive device
Most damages of diaphragm valves are not because of using in the producing process, on the contrary, because of mechanical compression that causes damage. Although the diaphragm of diaphragm valves have different levels of flexibility, different coatings, and different PTFE shield, but for all diaphragm valves are invisible from the outside about the wear and tear (caused by internal media surface corrosion and particulate attachment). Therefore, in order to avoid the forced stop production caused by damage of diaphragm valve in aseptic process production, in practice, we usually replace the diaphragm before the period of specified service life. As a result, no matter it is forced to replace the diaphragm numbers, or the resulting maintenance costs, or equipment downtime, is more obvious than PTFE bellows valves, while another advantage of the bellows valves: almost can be used for all kinds of process production.
Core components
Vesta bellows valve key components are the globe bellows that manufactured by TFM1705 PTFE, which in addition to various chemical media corrosion resistance, TFM1705 materials also meet the FDA Code of Federal Regulations Article 21 of § 177.1550 on "perfluorocarbons resin" requirements. Its smooth surface (Ra ≤ 0.8mm), reliable sealing, larger switching movement distance and these characteristics are very beneficial for optimal CIP / SIP disinfection. More than three years, this bellows valve with patented technology is successful foothold in the market, and can strictly isolate the atmospheric environment of internal and external pipes in aseptic processes pipelines.
