Vibrators and types of vibrators used for compaction

Here we'll study-

 what's vibrators?

Why we use vibrators?

What are the kinds of vibrators?

 After reading this post you'll be ready to identify which sort of vibrators are used for various concreting work 👇👇👇

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Vibrators and kinds of vibrators

Types of Vibrators

Internal vibrators 

Surface vibrators

 Form vibrators

1. Internal Vibrators:

• an indoor vibrator is additionally referred to as needle vibrator.

• an indoor vibrator essentially consists of the three components.

Internal vibrators

(a) Power unit:

 It are often either a patrol engine or electric supply unit.

(b) Flexible tube: 

It is a rubber  tube having power connecting device at one end and vibrator head on the opposite end.

(c) Vibratory head:

 it's a straight iron tube having eccentric weight fitted inside it.

As soon as current passes through the tube, the vibration  results by the rotation of the shaft at high speed usually more than 7000 r.p.m. which are transferred to the concrete particles.

The diameter of the needle varies from 2.0 cm to

17.5 cm and length from 25 cm to 90 cm.

• The frequency of vibration may be from 10,000 to 15,000 cycles per minute.

The bigger diameter needle is employed within the construction of mass concrete work.

• The vibrating head should be immersed vertically within the concrete and will be kept inside the concrete.

• at the time of running the vibrator, its bearing should be kept cool to reduce breakdown.

As soon  the Concrete  consolidates, its surface level falls and surface becomes smooth.

Air bubbles could also be seen breaking at the surface.

• When these bubbles cease to seem on the surface, the concrete could also be assumed as compacted sufficiently.

The vibrator should be lowered vertically within the concrete and when the concrete is compacted it should be withdrawn vertically slowly at the speed of about 8.0 cm/sec.

At this speed the withdrawal hole caused will fill itself without entrapping air within the concrete. Now, the vibrator is inserted at another point at a distance of fifty cm to 100 cm.

Time of Vibration:

• The time of compaction by the interior vibrator depends on the consistency of the combination .

• Usually from 5 to 30 seconds compaction is sufficient counting on the consistency of the combination .

2. Surface Vibrators:

• These vibrators are wont to compact horizontal concrete surfaces on roads.

They impart vibration at the surface of the concrete.

• The frequency of those vibrators vary from 3000 to 6000 cycles per minute.

Types of surface vibrators:

a) Vibrating screed
b) Pan type vibrator
c) Plate type tamper
d) Vibratory rolling screed

3. Form Vibrators:

• These vibrators are external vibrators and are attached to the surface of the concrete form work.

• They vibrate the formwork and successively formwork vibrates the concrete.

• This class of vibrators generally are utilized in large precast concrete plants.