Categories: Machinery

Diaphragm pump: types and design of diaphragm pumps

Thanks to the development of technology, new types of equipment and technical means regularly appear on the modern market, meeting the higher requirements of consumers. The diaphragm pump can be carried to such equipment also, which is also called diaphragm. The main working body of this pump is a membrane (diaphragm), the principle of operation of this mechanical three-dimensional device is based on the reciprocating motion of which. Forced and with a certain cyclicity changing the size of the working chamber of such a pump, with its help it is possible to carry out pumping as liquid, and gaseous media.

Diaphragm vacuum pump in explosion-proof design

Principle of operation and design features

The main elements of the design of the diaphragm pump, which are located in its fixed body, is:

movable diaphragm or membrane;
working chamber of the device;
stock (piston), which connects the diaphragm to the drive shaft;
crank mechanism;
valves, which prevent back suction is pumped;
inlet and outlet pipes.

Diaphragm pump with mechanical drive

In that case, if the diaphragm pump is used for laboratory purposes, it is equipped with vacuum gauges, protective filters, as well as additional elements of automation, which protect such a device from possible overloads and associated losses.

Depending on the model, diaphragm pumps can have one or two working chambers. Models with one camera are a typical option for such equipment and are used most often. Two-chamber diaphragm pumps, whose cameras can be connected in series or in parallel, are used in those cases, when the use of more powerful pumping equipment is required.

Internal device of the diaphragm pump

The principle of operation of the diaphragm or diaphragm pump is as follows.

At the moment of starting the pump, the rod, associated with an elastic membrane, begins to bend it to the side, opposite to the working chamber, resulting in the volume of this chamber increases.
Due to the sharp increase in volume in the working chamber creates a vacuum effect, and in it through the inlet pipe begins to enter the pumped medium.
By means of the crank mechanism the return movement is reported to a membrane, and the volume of the working chamber decreases sharply, which leads to ejection from it is pumped through the outlet. At that moment, when the membrane begins to reverse, the inlet pipe is automatically locked by a special valve.

Diaphragm pumps of some models are equipped with two diaphragms at once, which are located opposite each other and are connected by an eccentric mechanism. Due to that, that the pumping of the medium is carried out alternately on each of the membranes, the use of such devices is more efficient.

Operating strokes of the double-diaphragm pump

Some manufacturers use structured diaphragms for pumps. Along with other benefits, membranes of this type have an extended service life, in accordance, less often need replacement, which makes their use more cost-effective.

Structural elements of diaphragm pumps during operation can come into contact with different types of working environments and be exposed to their active influence. That is why, depending on the purpose of the vacuum diaphragm or diaphragm pump, you should choose models, which are designed for those types of environments, with which such a device will work. If you ignore this requirement and choose equipment with inappropriate specifications, you can face that, that it will fail very quickly.

Types of diaphragms for equipping diaphragm pumps

Quite naturally, what of that, what type of diaphragm is used to equip diaphragm pumps, depends not only on the durability of such equipment, but also the effectiveness of its use. According to the design, there are three main types of diaphragms for pumps.

The simplest in design flat diaphragms allow you to achieve a high degree of compression. The connection of such a diaphragm to the rod is made through the hole, specially made in its central part. The presence of such a hole often causes deterioration of the tightness of the membrane, which can begin to flow into the second chamber of the pump is pumped to them Wednesday. in addition, threaded connection elements, by means of which the membrane is connected to the rod, are in constant contact with the pumped medium, which is often undesirable.
The molded diaphragms are connected to the pump rod with a screw, pressed into a disk of convex shape, which is installed on the back of the working chamber. So, when using similar membranes for pumps contact is pumped out with metal fasteners is excluded. Meanwhile, diaphragm pumps, on which diaphragms of this type are established, characterized by lower productivity. This is due to the fact, what, compared to flat models, convex membranes have less elasticity.
Highest performance, Diaphragm pumps are characterized by maximum service life and minimum maintenance costs, on which structured diaphragms are installed. Such membranes, in addition to a specially designed form, differ in the improved mechanical characteristics. When using these membranes virtually eliminated leakage is pumped, in addition, the latter does not come into contact with metal fasteners.

Diaphragms for pumps. Top row - soft santoprene (similar to rubber), bottom row - Teflon (tougher)

scope of use

Diaphragm pumps due to the peculiarities of their design are completely sealed devices, therefore the environment, which can be pumped with their help, does not come into contact with the surrounding air. It is due to this quality, as well as the principle, on which diaphragm pumps work, their use is especially relevant in those cases, when sterility and absence of leaks of the pumped environment are important. Use of completely sealed diaphragm pumps, which is also important, allows you to protect people, which are next to them, as well as the environment from the harmful effects of the environment, pumped, if it is characterized by high toxicity. Vacuum devices, in contrast to mechanical pumps, are oil-free equipment.

Diaphragm vacuum pumps due to the above qualities are most actively used in the following areas:

medical and pharmaceutical industries;
food and beverage production;
nuclear industry;
printing;
laboratories of various orientations;
maintenance of chemical processes at various enterprises, which requires a diaphragm dosing pump;
production of paints and varnishes, where not to do without diaphragm dosing pumps;
equipping various vacuum systems - filters, suction cup, massagers, manipulators, etc..

Diaphragm pneumatic pumps for the chemical industry are available in polypropylene or aluminum housings

Diaphragm type pumps, as mentioned above, are needed not only for gas pumping, for water and other liquid media. The use of diaphragm pumps as dispensers is common. In particular, diaphragm dosing pumps are successfully used in chemical plants, where they are used to perform dosing and mixing of reagents, in the oil refining industry, at desalination stations, etc..

High pressure diaphragm pump allows you to create a clean vacuum in different containers or other closed systems. in addition, such equipment can be used as a pneumatic compressor.

The Triplex high pressure diaphragm pump is used in spray systems, filtration, cooling or dosing

Diaphragm-type vacuum pumps are often used to equip dairy farms, where with the help of such devices individual milking machines are activated. The diaphragm pump differs in the compact sizes, which allows you to easily place it on carts, which milking machine operators transport together with cans on the farm territory. Importantly, that the operation of vacuum diaphragm pumps creates a minimum of noise and vibration. This is due to the lack of rotating parts in their design. Other advantages of using diaphragm pumps to equip dairy farms are:

resistance to high humidity;
ensuring high purity is pumped;
efficiency of the device in terms of energy consumption;
affordable price.

benefits of use

What are the advantages of diaphragm pumps? Such devices:

are durable (which is higher, than similar equipment of other types due to the lack of details in the design, rubbing);
have high reliability;
do not require frequent maintenance due to the simplicity of design;
do not require the help of qualified specialists to replace worn parts;
characterized by high versatility;
differ in the minimum level of noise and vibration at work;
do not require lubricants;
simple and easy to use.

Industrial diaphragm pump, designed for hydraulic transportation of solid materials (mining waters, breed sludge, etc.. P.)

Choosing diaphragm pumps, which in the modern market are represented by a wide variety of models, you should pay attention to the following parameters of such devices: