In the dictionary by V. Dahl, "a seal is a hanging lead seal." Initially, it was applied to goods at customs. Lead is a soft plastic metal on which it is easy to put any print, and the seal cannot be removed without damaging the drawing. The same property of a lead seal is used today, despite the fact that its appearance and significance have become easier over time.
A bit of history
The oldest seals preserved today were made in the VI-VII millennium BC.
Historically, a seal was not just protection against illegal entry, it was a sign of power, a sign of property, and a talisman. The first fillings were made of wax and sealing wax. Then, in the XIV century (in any case, archaeologists found West European trade seals of this age), lead seals appeared, which were improved and modified, but still exist, although they have been pretty much replaced by modern locking and sealing devices.
In Central Asia, lead seals served as actual confirmation of crossing the customs border of Bukhara. They were superimposed on certain groups of goods at Samarkand customs, were removed already at the border and returned to Samarkand, and merchants received the corresponding remuneration.
In nineteenth-century Russia, a lead seal is already an indispensable attribute of commercial equipment. Each manufacturer or merchant had his own trade seal, and for safety, all goods sent on the way were sealed. At the beginning of the last century, all goods were sealed, including perishable dairy products. The surviving trading lead seals of the time are valuable evidence of history. According to them, one can trace the development (in modern terms) of the light, food industry, freight transportation and trade relations in the Russian Empire.
What is a lead seal
Lead seals GOST 30269-95 (bank or collector) are small discs with two through holes 2.5 × 2 mm, into which a sealing wire or twine is threaded, on the one hand and a recess on the other side for the assembly. When an imprint is placed on the seal correctly placed on the wire, the wire and the assembly are clamped in the seal.
The standard diameters of lead seals are 8 mm, 10 mm, 16 mm, height - 5.5 mm, 6.5 mm and 7.2 mm, respectively. There are special lead seals for jewelry with a diameter of 3.5 mm.
Lead seals are made from soft primary lead of brands C0 and C1, since secondary lead is a product of processing lead-acid batteries, and there may be acid residues on it.
In addition, such lead has slightly different mechanical properties, it becomes less viscous. Therefore, the most reliable and environmentally friendly lead seal, the manufacturer of which monitors the quality of not only the products themselves, but also the materials from which they are made.
Large manufacturers, firstly, do not use waste and battery lead, and secondly, conduct radiation and chemical testing of lead.
Use of lead seals
Lead seals are installed on any objects, whether it is closed doors, devices, appliances, goods. A sealer with a unique impression can be located in one person, and therefore it is impossible to replace the installed seal.
In banks, with the help of lead seals, vaults, collection bags and cash bags are sealed.
They are also used during the transportation of goods in sea and railway containers and trucks, when storing goods and valuables in warehouses, for daily sealing of premises in order to avoid unauthorized entry, their detection and possible theft or substitution of valuables.
Lead seals are also used for sealing transformer substations, metrological equipment, various measuring instruments, for example, gas and electric meters.
Sealer and sealing wire
Lead seals are installed using a special tool. These are metal pincers (sealer), the complete set of which includes metal dies with a diameter of 10 mm, on which convex or indented letters, numbers, small characters are engraved. The number of characters on the dice is limited. When squeezing the cheeks of ticks, the lead seal (photo below), placed between them, is deformed, and a unique image is obtained on it.
For sealing, a special twisted-wire twisted wire is used. One core - the direct central - serves as the basis, the second twisted - secondary. Relief coils reliably hold the installed seal, preventing it from sliding.
A special technology for the manufacture of wire increases its resistance to atmospheric and mechanical stress, and most importantly, to criminal tampering.
Typically, wire is produced in coils weighing one kilogram.
Installation of lead seals
To install a seal, you need to cut a piece of wire or jute twine of the desired length, pass it through the eyes of the object that you want to protect from breaking, then into the holes of the seal, pull it as close to the eyes as possible and squeeze it with a sealant. Then you need to check the reliability of the installed seal - it should not move along the wire.
Apparent simplicity of installation with insufficient preparation of the installer of seals can lead to problems. Specialists should know the weaknesses of the seals, be able to simulate unauthorized access scenarios, distinguish between its signs, as well as signs of substitution of the sealant.
Seals and sealers must be strictly taken into account, transferred in compliance with the rules, which exclude the possibility of unauthorized access to the sealing devices.
Sealing should also be carried out according to the rules, with a record keeping journal of the seals.
How to remove a lead seal
You can remove the lead seal by cutting the tourniquet with scissors or by biting the wire with wire cutters. It will not be possible to restore the connection, you just need to install another seal.
Some "specialists" manage to remove the seal and then install it in place, heating it. When heated, the grooves expand, and the seal is pulled off the wire. Therefore, it is desirable to tie the ends of the wire after threading into the holes with a knot, then again thread them into the grooves in the opposite direction, and then tightly clamp the seal with a sealant.
For authorized removal of the seal, the rules must also be followed. Before removing the seal, you need to inspect, make sure its integrity, make a mark in the accompanying documents or magazine.
If it is found that the seal is damaged or torn, then the acceptance of the sealed values is carried out in the presence of a commission with the drawing up of an act, which must indicate the state of the seal and wire.
Advantages and disadvantages of lead seals
The main advantage of using lead seals is their low cost and ease of installation. In addition, they are able to tolerate high and low temperatures, their differences.
Manually without an additional tool, which, however, is not difficult to access, remove, all the more imperceptibly, a lead seal is not easy.
An individual impression on the sealer, which is difficult to manufacture, makes it difficult to fake and replace the seal. If you wish, of course, you can overcome any obstacles, for example, bribe, somehow influence the employee who is responsible for the sealer, or order a duplicate print.
After the plastic security seals appeared, they began to say that the disadvantage is the large weight of the lead seal, although one seal weighs about 4 grams, and about 250 pieces with a diameter of 10 mm per kilogram. It is unlikely that in one round you will need to seal so many doors or so many bags of cash, and even more so sea containers, so that the total weight of the seals and wire becomes tangible.
Equipment for the manufacture of lead seals
Small manual machines for the production of lead seals from different manufacturers look about the same, and the process is the same. Lead melts separately in the crucible, then it is poured into the form of a mechanical device with two handles. The sprue is cut off by one of them (the extension into which the lead is poured) when the lead in the mold solidifies, and the second seals are pushed out. The productivity of manual machines varies from 35 to 70 kg of lead seals per shift.
There are also small electrical installations with a capacity of 20 kg of products per hour and semi-automatic machines with a capacity of 25 kg / hour.
Lead Seal Manufacturers
There are many large companies in Russia, the list of activities of which includes the production of lead seals. Almost every major city has its own manufacturers of lead fillings. As a rule, these companies are engaged in the manufacture and supply of access control systems and security devices and cooperate with large customers: banks, factories, transport companies, shops.
They have their own production, a good numerically controlled machine tool fleet and qualified specialists, which allows them to produce high quality products at low prices. Engraving equipment allows you to perform any clear image on the dies of the sealer at the request of the client.
Today, there are many sealing devices that are more modern than a sealer with lead seals and a sealing wire, but it is too early to write off old, tested not for decades, but for centuries, lead seals.