Bulroc (U.K.) LTD

Manufacturers of Rock Drilling Equipment

Profile

Bulroc U.K. Ltd has been involved in the design and manufacture of Percussive Down Hole Rock Drilling Equipment since 1967. The company originally traded as Weaver & Hurt Ltd., but in 1989 it was decided to change the name to its present one of Bulroc U.K. Ltd. The name Bulroc has always been the company's trademark and by this time the name Bulroc had become internationally known, so it was logical to change to this more recognizable name.

The first Bulroc Down Hole Hammer was introduced in 1976, and with its success other sizes and models were gradually added to the range so that within the space of a few years Bulroc had developed a series of valved and valveless hammers for drilling hole sizes ranging from 2.36" through 9.84".

As Down Hole Hammer development continued, so did a range of complimentary products, including Shock Absorbers, Drill Tubes, Hammer Extractors, etc.

Early in 1984 the company made a significant investment in plant and equipment necessary for the design and manufacture of a range of Button Bits to suit not only Bulroc Hammers but also all other makes of popular DTH Hammers.

At around this time Bulroc developed the world's first Reverse Circulation Hammer for the Mineral Exploration Industry, a system that has now become widely accepted, particularly for gold exploration.

In 1993 Bulroc introduced the Hyper range of Hammers to replace the original valveless design. Larger sizes of Hammers were developed, so that currently Bulroc produces Hammers and Button Bits capable of drilling up to 43.31" in diameter.

During 1985 Bulroc introduced a range of Eccentric Overburden Drilling Systems, Bulroc ODS - for the continuous casing of holes through unstable ground conditions. Over the years this range has been extended to include the Bulroc CDS Concentric Overburden Drilling Systems, a design that is essential for the efficient casing of large diameter holes.

Bulroc products are produced in a modern factory located in the heart of England some 155 miles north of London and employs the latest computer technology in its design and manufacturing facilities.

Bulroc U.K. Ltd has a policy of continuous product development aimed at improving the existing range, whilst at the same time introducing new products to increase and extend the already wide applications for Down Hole Percussive Rock Drilling.

BULROC HAMMERS

	BULROC Valved Type Hammers - BR 1, 2, 3, and 33 Bulroc Valved Hammers are still available in this limited range to fulfill the requirements for small diameter drilling where generally only low operating air pressures are available. The BR Valved designed Hammer is particularly efficient at low operating pressures.
BULROC Hyper Hammers - Hyper 31, 41, 51, 63, and 81 Bulroc Hyper Hammers are a valveless design which operates successfully and efficiently over a wide range of pressures. Simple in design, with a minimum number of components, and manufactured from the highest quality materials makes the BULROC Hyper range popular in many fields of applications around the world. All Hyper Hammers are available with alternative chuck options. Hyper models 31, 41, 51, and 63 are also available in a Heavy Duty format.

BULROC REVERSE CIRCULATION HAMMERS

	Developed from the original center sampling RC Hammer, the Bulroc RC range provides the mineral exploration industry with an uncontaminated sample and up to 97% recovery. Bulroc RC Hammers are available in 4" and 5" sizes, together with RC bits, dual wall drill pipe, and many other accessories for RC drilling.

Click here to go to RC Hammer page

HAMMER LUBRICATION ACCESSORIES

	Hammer Lubricating Oil Bulroc 330 or Bulroc 350 Lubricant - These lubricants have been specifically developed for use with DTH hammers and incorporate the necessary emulsifying additives to deal with the varying amounts of water which inevitably occur in the system even when "dry drilling."		Thread Grease Bulroc recommends the use of Bulroc 500 anti-seize thread compound when making up threaded joints on your Hammer and Drill tubes. Bulroc 500 is copper and molybdenum-based grease with a friction coefficient of 0.15 and is specially engineered to withstand the high pressures and temperatures encountered in DTH hammer drilling.
	Oil Lubricators Using an in-line DTH hammer lubricator is extremely important to achieve optimum drilling efficiency from your hammer. It can help prevent premature failure and deterioration of your hammer.		Bulroc can provide pressurized oil lubricators in capacities 5, 10, and 15 liters with 1 1/2" compressor hose connections. The sturdy units operate to maximum pressure of 392 PSI, but are tested to 595 PSI. Other oil lubricator combinations are available on request.

BULROC BUTTON BITS An extensive range of Button Bits to suit all popular types of Down Hole Hammers in a wide variety from 2.36" through 4.33" in diameter. Bulroc Down Hole Button Bits are available in normal or heavy duty formats, flat face, convex, and concave with hemispherical, ballistic, and parabolic inserts depending on size and type of bit to give maximum choice for all rock conditions.

BULROC LARGE DIAMETER HAMMERS

An Introduction to "Big Hole" Drilling

In today's foundation drilling industry the need for faster and more accurate methods of producing large diameter cased and no cased holes has resulted in the development of Bulroc's Big Hole range of DTH percussive rock drilling products capable of drilling holes larger than 3.28 feet (1 meter) in all rock conditions.

The Bulrock range of DTH hammers now includes the Hyper 181, Hyper 241, and Hyper 301S, which when used with Bulroc's extensive range of continuous casing systems will give one of the world's fastest cased pile drilling systems, capable of penetrating all types of ground conditions whilst still being able to produce a cased rock socket in excess of 3.28 feet in diameter.

Prior to the availability of these large diameter DTH products, bored pile holes were commonplace, but due to varying ground conditions their slow penetration rates were measured in hour/3.28 feet. Using the Bulroc Big Hole range of equipment, penetration rates can now be measures in 3.28 feet/hour, providing huge savings in both time and money.

The greatly improved production rates mean fewer rigs are required to produce a given number of piles in a specific time period and, consequently, plant costs are also drastically reduced.

Bulroc realized very early in the development of their Big Hole range that existing bored pile contractors would not always be prepared to invest in expensive purpose-made drill rigs that would allow them to change to DTH percussive equipment. For this reason Bulroc has developed relatively inexpensive methods of converting both hammered pile and bored pile rigs into DTH rigs, allowing the contractor to experience these greatly improved penetration rates with minimal outlay for new plant.

Bulroc's Big Hole range can be used on just about any drill rig with a top drive rotation head that has sufficient torque and pull down (weight on bit). These factors will vary depending on the size of the hole to be drilled, but as a guide a 24.02" diameter hole will ideally require a rotation unit of 2.5 to 3.0Tm torque at rotation speeds down to 4 rpm. The drill rig should have the capability of applying and maintaining a "weight on bit" of 5.5T. This means that the drill rig needs to have the ability to apply this 5.5T pull down when drilling commences, but also has the capability of holding back the additional weight that will be applied as more cased drill pipes are added.

The Big Hole range can also be used on Kelly bar machines by simply fitting a suitable hexagon connection to the bottom of the Kelly, providing there is sufficient height below the Kelly to accept the hammer and drill bit.

Big Hole Hammers

The Bulroc Hyper 181, Hyper 241, and the new Hyper 301S are all valveless hammers and are all basically similar in their design and construction. High quality materials and carefully controlled heat treatment come as standard.

These three hammers have a through bore wearsleeve with no inner cylinders and no internal porting to ensure maximum strength.

The piston is the only moving part, and its cycle is determined by the sturdy control tube.

The Hyper 181, Hyper 241, and Hyper 301S are all large hammers, and whilst economical for their size they do require a substantial volume of compressed air for their efficient operation. Consequently, the exhaust air is generally sufficient for effective hole cleaning.

When setting up the drill string for Big Hole drilling, care is taken to ensure that the drill pipe and usually also the hammer are correctly sleeved or cased to ensure efficient hole cleaning with the exhaust air available.

However, in certain particular circumstances where the hammer exhaust air alone is not sufficient and extra flushing is required to maintain efficient flushing, a hole may be drilled in the base of the control tube to allow additional high pressure air straight through the hammer to supplement the exhaust air.

All Bulrock Big Hole hammers are supplied as standard with a check valve arrangement that helps maintain pressure in the hammer when the air is turned off and so prevent the ingress of water and cuttings from entering the hammer, which could cause potential problems.

The chucks on all three hammers are designed to house replaceable nylon drive plates that eliminate spline wear when correctly maintained and consequently prolong the life of both chuck and bit.

The trapezoidal twin start thread of both chuck and backhead minimize the force necessary to break open these components for bit replacement or servicing. If a suitable hydraulic break out tool is not available or if the drill rig does not have an adequate break out arrangement, then the thick breakout washers can be cut through to release the thread connection.

The Hyper 181 hammer has an 8 5/8" API reg pin backhead and a chuck to suit Numa 180 shanked bits. However, this hammer can also be supplied with a chuck arrangement to suit Mission SD18 shanked bits. In this instance, the drive plates are replaced with drive rods.

The Hyper 241 is supplied as standard with an 8 5/8" API reg pin box backhead, but can also be supplied with an 8 5/8" API reg pin if preferred. This should be specified at the time of ordering. The chuck is designed for Numa 240 shanked bits.

The Hyper 301 has a 10" BECO pin thread backhead, but can be supplied with an 8 5/8" API reg box if preferred. The chuck is designed for Mission XL24 shanked bits.

As with all DTH hammers, a constant supply of the correct type and quantity of rock drill oil is extremely important. These costly products can be irreparably damaged in seconds if the lubrication supply fails. A well-lubricated hammer is generally a trouble-free hammer.

A Typical BIG HOLE Drilling Arrangement

1. Shock Absorber - The "out of hole" shock absorber is optional and will depend on the ability of the rotation head to accept a reasonable level of vibration from the hammer. Bulroc proposes the "out of hole" option since much of the vibration from the hammer will be absorbed by the drill string and so extend the life of the shock absorber. By positioning the shock absorber beneath the rotary head, it eliminates a potential loss of expensive equipment in the event of a connection failure should the shock absorber be positioned behind the hammer.
   
   
2. Air Inlet Swivel - Generally these rigs may not have the facility to pass the necessary volume of compressed air through the rotation head, and in such cases an air inlet swivel is required. This needs to be of a size and design that will pass large volumes of air with minimum restrictions. At this point it is important to emphasize that an air receiver must be positioned between the several compressors that will be required to produce the necessary air volume and a suitable oil lubricator before connecting to the air inlet swivel. A simple manifold system is no substitute for an air receiver and will only result in a throttling effect of the weakest compressor, which will effectively reduce the availability of the total air package, with a corresponding reduction in the performance of the DTH hammer.
   
   
3. Sleeved Drill Pipe - On "Big Hole" drilling, hexagon drill pipe now replaces the former threaded type. The drill pipes will generally be sleeved out to a particular diameter to provide for the most effective hole cleaning or "up hole velocity" relative to the diameter of the drill bit. Reinforced holes through the sleeve allow "rebar" or similar steel bar to be inserted to hold and support the drill string when adding or removing drill pipe. No more spanners, no holding forks, and no greasing; a fast efficient way of handling large diameter drill.
   
   
4. Saver Sub - The hammer is connected to the hexagon drive drill pipe by way of a thread to hexagon saver sub, although a hammer with a direct hexagon connection can be supplied on request.
   
   
5. Sleeved DTH Hammer - The DTH hammer is sleeved to the same diameter as the drill pipe to provide an even flow for more efficient hole cleaning. There are different designs of hammer sleeves, the one shown in the illustration is a bolt-on design, but Bulroc can offer other designs.

BULROC Large Diameter Hyper Hammers Hyper 121, 181, and 241 These are of a different design to the smaller range of Hyper Hammers and have been developed for the Construction Industry using either conventional-type Button Bits or, more generally, with Overburden Drilling Systems.

BULROC ECCENTRIC AND CONCENTRIC OVERBURDEN DRILLING SYSTEMS

In most cases the pile will be drilled in overburden and unconsolidated ground until solid rock is reached where the socket can be formed. Whether the socket is required to be cased or uncased, it will still be necessary to use a continuous casing system such as the Bulroc CDS.

The Bulrock CDS is a concentric overburden drilling system specifically designed for the continuous casing of large diameter holes down to and into solid rock. The specification of the pile and depth of socket will determine the practicality of producing the complete socket with the CDS, or closing and removing the system once bedrock is reached, and then completing the socket with a conventional drill bit.

When drilling commences the cutting segments are extended to cut a hole slightly larger than the casing diameter. Depending on ground conditions it may be necessary to inject water through the air system to lubricate the hole and keep the cutting segments free. When bedrock is reached, the cutting segments can be closed by rotating the CDS anti-clockwise against the solid base of the hole or by pulling up against the casing shoe and rotating anti-clockwise. The complete drill string, hammer, and CDS can be removed from the hole, leaving the case in place.

The Bulroc CDS is designed with ease of servicing in mind combined with operating economy. The pilot bit, that assists in producing a straighter hole compared to flat face systems, can be removed for replacement or refurbishing by extracting the two locking pins in the driver. This also releases the cutting segments and exposes the drive pins for checking and replacing as required. Bulroc offers the option of a solid drive shoulder or a replaceable drive ring to mate with the casing shoe.

Bulroc CDS Overburden Drilling Systems are widely used in a variety of applications from Well Drilling to Mini Piling, Rock Anchoring, to Site Investigation. The new range of Concentric design Overburden Systems is available in a variety of sizes up to the CDS1100 for large diameter Bored Piles up to 50" in diameter. The ODS range of Eccentric Drilling Overburden Systems is available for smaller hole sizes. The ODS 90 is the smallest system, designed for 3" hammers, and produces a 4.88" diameter hole. Other systems are available for hole sizes up to 12.05" in diameter.

Click Here For Bulroc Overburden Systems Specifications

Bulroc Eccentric Overburden Drilling Systems
ODS 90	Drilled Hole Diameter 4.88" Casing Size 4.5" O.D. x 3.96" I.D. Complete System: BR3, BR33, and Mach 33.		ODS 115T	Drilled Hole Diameter 6.1" Casing Size 5.51" O.D. x 4.88" I.D. Complete System: DHD340A, SD4, and Cop 42.
ODS 115W	Drilled Hole Diameter 6.1" Casing Size 5.51" O.D. x 5" I.D. Complete System: DHD340A, SD4, and Cop 42.		ODS 140	Drilled Hole Diameter 7.4" Casing Size 6.63" O.D. x 6.06" I.D. Complete System: DHD350A and SD5.
ODS 160	Drilled Hole Diameter 8.46" Casing Size 7.63" O.D. x 6.85" I.D. Complete System: DHD360 and SD6.		ODS 165	Drilled Hole Diameter 8.46" Casing Size 7.63" O.D. x 7.13" I.D. Complete System: DHD360 and SD6.
ODS 190	Drilled Hole Diameter 9.33" Casing Size 8.11" O.D. x 8.62" I.D. Complete System: DHD360 and SD6.		ODS 215	Drilled Hole Diameter 10.87" Casing Size 10" O.D. x 9.45" I.D. Complete System: DHD380 and SD8.
ODS 235	Drilled Hole Diameter 12.2" Casing Size 10.75" O.D. x 10.02" I.D. Complete System: DHD380 and SD8.		ODS 240	Drilled Hole Diameter 12.2" Casing Size 10.75" O.D. x 10.24" I.D. Complete System: DHD380 and SD8.
Bulroc Concentric Overburden Drilling Systems
CDS 240R	Drilled Hole Diameter 11.65" Casing Size 10.75" O.D. x 10.24" I.D. Complete System: DHD380 and SD8		CDS 280R	Drilled Hole Diameter 13.58" Casing Size 12.76" O.D. x 12.01" I.D. Complete System: SD10 and N100
CDS 280	Drilled Hole Diameter 13.39" Casing Size 12.76" O.D. x 11.97" I.D. Complete System: SD10		CDS 365	Drilled Hole Diameter 16.73" Casing Size 15.98" O.D. x 15.24" I.D. Complete System: N125
CDS 460	Drilled Hole Diameter 20.87" Casing Size 20" O.D. x 19.02" I.D. Complete System: N125		CDS 510	Drilled Hole Diameter 22.95" Casing Size 22.01" O.D. x 20.98" I.D. Complete System: N180
CDS 560 R	Drilled Hole Diameter 22.95" Casing Size 24.02" O.D. x 23.23" I.D. Complete System: N180		CDS 610	Drilled Hole Diameter 27.36" Casing Size 25.94" O.D. x 24.92" I.D. Complete System: N180 and N240
CDS 745	Drilled Hole Diameter 33.07" Casing Size 32.01" O.D. x 30.71" I.D. Complete System: N240		Bulring	The Bulrock Bulring range is ideally suited to horizontal drilling through all types of ground formations, from gravels and boulders to solid rock

BULROC Drilling Accessories

Shock Absorbers - Hammer Extractors - Drill Tubes and Adapters - Fishing Tools

Bulroc offers a range of accessories to complete the range of Down Hole Drilling Equipment.