GOST, which has a number 28191-89, regulates such a product as a worm clamp. This device refers to clamp fixing elements, which are used for joining hoses, hoses, and various tubes. The worm clamp has several varieties that have their own design features and are indispensable in many situations.
Worm clamp - an indispensable device for attaching various hoses, pipes, sleeves
Content
Where is it used?
Today, such products are very popular for connecting individual elements in pneumatic and hydraulic structures. The sizes of such devices are determined in accordance with GOST and depend on the following indicators:
- varieties;
- manufacturing method;
- series of fixtures.
Worm clamps are made as a single carbon steel structure and have an additional protective layer of galvanization. The galvanized coating, among other things, differs in that it is processed by chromation.
Consider the main structural elements that make up such a device:
- a tape on which there is a gear track;
- screw to tighten the clamp.
The clamp structure is very simple - it consists of a metal tape and a screw for tightening it
This design provides excellent sealing performance and uniform tightening. The screw can have a variety of, from a structural point of view, heads:
- hex head
- a head having a slotted groove;
- a head having a groove in the form of a cross;
- a head with a shoulder.
Note! The body of the clamp joins the tape at the same level without the use of welds or special connecting rivets. This eliminates the possibility of damage to the sleeve or hose during installation of the connection or during operation.
The tape, as a rule, is stamped and has special teeth. The edges of the tape must be rounded to avoid damage to the connected elements. In the process of tightening the screw, the housing abuts against the hooks. This provides a secure fit during tightening.
Types of worm clamps according to GOST 28191
In accordance with GOST, four main types of worm clamp products are distinguished. Consider them:
- A worm belt product that includes a bolt. Such a clamp can be of two series:
- light
- heavy.
Lightweight clamp is used in systems where there is no strong vibration
Such devices are operated under conditions of minimal vibration in the system.
- A narrow band-type clamp is used in structures that create strong vibration during operation. Such products are also equipped with bolts.
- A wide belt product equipped with bolts is used for sleeves that are characterized by low pressure indicators.
- Wire type product (equipped with screw).
The most popular clamp, which has teeth placed at a certain angle. Such teeth are made by corrugation. The presence of teeth eliminates the possibility of a collapse of the clamp even in difficult operating conditions (with strong vibration or mechanical stress).
Perforated devices have one feature - perforation on the tape.The stainless steel perforated worm clamp has weaker resistance to fracture. The destructive moment of such a device can be up to 15 Nm. The fastening element is tightened using different tools: a hexagon or a screwdriver. The tightening range is regulated by GOST and is about 6–76 mm.
Lamb clamps are the product most commonly used for industrial purposes.
It is worth paying attention to another type of worm gear - equipped with a “lamb”. Such a device is used, as a rule, in the domestic sphere, and not for production purposes. The cross section of such a worm clamp can vary from 10 to 60 mm.
A wing screw or, as this element is sometimes called a “butterfly”, allows you to install a clamp without using special tools. The body of such a clamp can be made of two types of steel:
- stainless;
- carbon.
The butterfly itself is often made of plastic. Such models are used for joining hoses and a variety of tubes.
All GOST 28191-89 worm clamps are classified according to the material from which they are made into three types:
- from stainless steel;
- galvanized models;
- combined devices, which include a durable element made of durable carbon steel, and the tape of such a device is made of stainless material.
According to GOST, clamps are made of durable steel, most often stainless
Technical requirements for worm clamps
GOST 28191 describes the basic requirements put forward for this product. Paragraph 2.1 states that all types of worm clamps, except for wire ones, should be made of carbon or stainless steel and have a tensile strength of not less than 40 kgf / mm².
Wire worm clamp products must comply with the basic rule - to be made from wire belonging to grade B and to the second class according to GOST 9389.
Products made of durable carbon steel must undergo additional anti-corrosion treatment (equipped with a layer of galvanization). Such a layer should have a thickness of at least 6 microns. Other coating options are possible.
All collars GOST 28191 should be able to be reused for hoses with the same cross-sectional indicators. When reused, they must not lose their sealing characteristics. The number of repeated applications should be at least 50.
Important! When pulling the clamp 1.3 times, there should not be any deformation manifestations, signs of wear, cracks, etc.
The surface of such a product must meet certain characteristics. It should be free from unwanted burrs, as well as any other deformation manifestations that may affect the performance of the product.
Each clamp is necessarily marked, the data on it allows, first of all, to determine the size of the product and manufacturer
According to paragraph 2.8 of GOST 28191, the outer side of the clamp must have the necessary marking. In the labeling, as a rule, two main points are indicated:
- First of all, the working diameter for it should be indicated on the outer surface of the clamp.
- The trademark of the company that manufactured this product is indicated.
Such clamps are packed in wooden boxes, which are laid out on the inside with special packaging paper. The weight of one such box should be no more than 32 kg.
Each box must be accompanied by a packing list, which indicates the following items:
- trademark of the manufacturer;
- Name of production;
- amount;
- designation of the standard;
- shelf life;
- date of assembly of the box.
On the outer surface of the box should be indicated by its mass. Designation is done with paint.
A few tips for using worm clamps
Consider some tips on the operation of worm clamps, regulated by GOST 28191:
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- Such products make it possible to make a reliable and tight joint of the pipe with the sleeve. In order to select the device necessary for the diameter, it is necessary to pay attention to its marking, to measure the pipe and sleeve in advance.
- Wide worm gears are recommended for use with a high level of vibration in the system.
- All worm gears, except for wire ones, should be used in structures whose pressure indicators do not exceed 7 MPa (70 atmospheres). The wire type of worm clamp product should be used in cases where the pressure in the system does not exceed 0.16 MPa.
