Raydets

Raydets are non-electric initiating device which combine the versatality and advantages of electric detonators and detonating cord. Raydet consists of a plastic tube carrying a very small quantity of reactive material on its inner surface. A No.8 strength instantaneous or delay detonator is crimped to one end of the ray tube. When initiated a low order shock wave with a velocity of 2000 mtrs/sec travels through the tube and reliably initiates the detonator. Raydets are reliably initiated by a detonator or detonating cord.

Raydets are designed for providing optimum blasting in terms of:

• Sequential Firing
• Optimum Fragmentation
• Reliability
• Avoidance of Ground Movement / Cut-offs
• Maximum Safety

The unique features of Raydets are:

• The shock tube (Raytube) is made of special co-polymer that can withstand high temperature variation
• Reactive material used is a highly reliable composition
• Highly moisture resistant
• Shock tubes have low order memory
• Simple and user friendly as hook-up connections are less cumbersome and time saving

Application

Raydet are designed for use in large hole stoping, ring hole blasting, tunnelling, blasting in highly conductive ore bodies, surface and trenching and other underground blasting operations, but not where methane or coal dust occur.

Products

The products offered for above mentioned blasting operations are:

1. Raydet HS 0 to 12 (13 period in half second series)
2. Raydet MS 0 to 20 (21 periods in millisecond series)

Specification

Raydet HS/MS specifications are as :

Nominal Delay Interval

Identification

(a) The delay nos are identified on the product as:

1. For halfsecond series :- Tags with delay number in BLUE.
2. For millisecond series :- Tags with delay number in RED.

(b) The tube lengths are indicated by binding tags attached to the coil with the length printed in Blue for half second series and in Red for millisecond series.

Packing

• Tubes upto 10.0 mtrs. :- 10 nos packed in a packet.
• Tubes 11 to 24.0 mtrs. :- 5 nos packed in a packet.
• The packets provide for details regarding tube length, delay number and nominal delay time.
• Quantity per case:-
  3.0 m to 10.0 m: 200 nos.
  11.0 m to 20.0 m: 100 nos.
  21.0 m to 24.0 m: 50 nos.
• Case dimensions: 555 x 315 x 390 mm (0.068 CBM)
• Case markings provides for indicating delay type, delay number and tube length.
• Raydets are packed in fibre board cartons.

Usage

Initiation of Raydets is carried out with Detonating Cord or Raydet TLD. The oval plastic yellow connector provided with each Raydet facilitates the hook-up of each detonator to the detonating cord trunkline. Raydets are also initiated by bunch blasting of upto 10 Raydet tubes using a wrap of detonating cord.

Advantages

• Raydet, being a non-electric system, is immune to stray currents, static electricity and Radio Frequency (RF) energies.
• Raydets eliminate the risk of misfire associated with electric detonators due to earth leakage in highly conductive ore bodies.
• Raydets can be safely used with pneumatically loaded ANFO, where there is a hazard of static charge being developed during loading.
• Raytube is insensitive to accidental initiation by impact, shock, friction and fire.
• Raydet provides accurate down the hole delay and in surface blasting provide true bottom priming.
• Raydet provides large number of sequential delays in combination with surface delays.
• Multideck initiation on different delays possible when needed.
• Bunch firing of Raydets possible enabling hook-up making less cumbersome and time saving.
• Raydet does not desensitize non-capsensitive explosives in the drill hole and thus ensures full energy release unlike Det cord.
• Raydet does not cause ejection of stemming or cratering effects commonly associated with detonating cord. This results in improved fragmentation, throw and reduced air blast noise due to better confinement.
• Bottom hole initiation reduce generation of flyrock from the bench top due to cratering effects.
• Avoids side initiation of explosive column.

Precautions During Use:

• Do not cut factory sealed end of Raydet tube.
• Do not connect two Raytubes. One Raytube will not initiate another.
• Where bunch firing of Raydets is adopted, do not connect more than 10 tubes in a bunch.
• Use the oval plastic connectors provided on the Raytube for hook up of Raydets onto Detonating Cord. Do not use tape.
• Storage temperature should not exceed 60 degrees Celsius.

Search GOCL

See Also:

All IDL Division Products

Raydet DTH (Down The Hole)
Raydet TLD (Trunk Line Delay)
Twindets

All Gulf Products