Alchatek Blog

Perhaps the most misunderstood functionality of mechanical packer design is the ball-valve placement.  The ball-valve placement is important because this is the functional element that keeps chemical grout in the substrate as it reacts and creates the density required to adequately seal the substrate.  It is an applicator error to remove the packers prior to full product cure.  Top-mounted zerk-valve packers allow for port-to-port travel observation.  Port-to-port travel is injecting one packer until chemical grout is observed exiting the next packer which does not have an anti-return zerk-valve installed.  Once the material is observed coming out of the next packer, the zerk-valve can be installed, and the process repeated (see FIGURE 7).  This is only possible with top-mounted ball-valve placement.  Another benefit of the top-mount packer is the ability to replace the standard zerk-valve with a button-top-valve (see FIGURE 8).  Button top valves, as mentioned above, minimize leakage with a more secure connection to the packer that doesn’t allow the coupler/packer connection to flex (see FIGURE 9).

Bottom-mount ball-valves (as seen below FIGURE 10) are less common in the industry.  The main benefit of bottom-mount ball-valves is the immediate removal of the top shaft following injection, and subsequent patching of the drill hole with the ball-valve still in the substrate.  Bottom-mount ball-valve packers commonly have a bit more leakage and excess chemical grout as the shaft, above the ball-valve, is full of unreacted and unconfined chemical grout.

Alchemy-Spetec supplies a complete offering covering all of the functionalities detailed in this brochure.  Below is a table detailing bottom-mount options and top-mount options.  Note: All top-mount options can be converted to button-top style with by adding the equal quantity of Button-Top Fittings, ACP-2203.

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Mechanical Packers come in many types. In the concrete repair industry, contractors will find plastic, steel, brass, aluminum, zinc, and other metal alloys. The most commonly used type is steel. Steel offers the benefits of strength and resistance to oxidation through chemical grout oxidizing components found in grouts such as acrylics. Brass and Aluminum packers are weaker and allow for the shaft to be broken off by hammer for more timely patching efforts following injection. However, most Quality Control Managers and clients will require the removal of all metal from the substrate prior to patching. The chosen method of removal is the choice of the client and/or design professionals.

There are two types of plastic packers used (see FIGURE 4). The 5/8” (16mm) button top packer is used for high volume applications and for applications in which a button-top coupler is preferred to minimize leakage. The free-floating ball in the middle of the packer acts as an anti-return valve. A 5/8” (16mm) plastic sleeve is inserted first, with the threaded plastic base then screwed into compression via the hex head top.  Another common port used is the 3/8” (10mm) plastic bang-in, or hammer-in port. These ports are simply inserted into a 3/8”(10mm) drill hole aided by the force of a hammer. The soft nature of the plastic allows the concrete to bite into the sides of the packer creating a compression seal. Because plastic packer compression is achieved through plastic to concrete friction, the overall pressure tolerances are typically lower than that of the mechanical packer counterpart.

Aluminum packers have recently become more prevalent in the industry due to the combination of economical pricing with the benefits of mechanical packer pressure tolerances (see FIGURE 5). Due to the softness of the components, however, these packers have been known to strip threads at times. All functionality considered, aluminum packers do offer a reasonably price alternative to the steel mechanical packers.

Alchemy-Spetec continues to offer a popular heavy-duty ½” (13mm) and 5/8” (16mm) packer with a soft grade of rubber and washer on the top of the packer that adds extra friction and bite to the concrete when tightened. The heavy-duty packer offering is in steel (see FIGURE 6). These heavy-duty packers are top-mounted ball-valve style and can be converted to button-top valve (see next section and below).

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Mechanical Packers are most commonly used in poured concrete substrates. In adequately consolidated poured concrete structures, the drill hole itself acts as a channel through which the chemical grout will travel as it reaches the cross-section of the crack or joint. In these conditions, only the entire rubber shaft of the mechanical must be recessed into the drill hole to create an adequate compression seal. In the example of a 3” long packer, this would leave approximately 1.5” of metal shaft for connection access from the coupler that connects the hose line to the mechanical packer. However, it is common to experience micro-spalling at the point of drilling as the drill catches the 45-degree drill line. In these cases, the packer must be set even further into the concrete to ensure the rubber is fully recessed into the drill hole. This condition decreases the length of shaft accessible at the face of the substrate for connection to the coupler and can present challenges for the applicator. For this reason, it is advised to utilize 4” or 6” long packers in deteriorated or defective concrete substrates (see FIGURE 3). 

Length can also be advantageous when the contractor is attempting to inject the material to a specific point within the substrate. For example, it may be desirable to deliver chemical grout to the backside of a 4” substrate, or to a certain depth for a pipe penetration, or to account or unknown consolidation of the concrete within the drill hole channel that could lead to lateral travel of chemical grout to undesired locations within the substrate. Each job-site and substrate condition is different, and length of mechanical packer can provide the contractor with more options and ultimately a more effective delivery of chemical grout.

Mechanical Packer diameter is relevant for two reasons, 1) this dictates the size of the drill hole required, and 2) the overall surface area of the rubber in the drill hole is a key contributor to the pressure tolerance of a mechanical packer. 

1. Size of drill hole considerations: Industry standards require 45-degree drilling to insert mechanical packers to a crack depth that is ½ the thickness of substrate.  For thin substrates, for example 6” thick slabs, drilling at a 45-degree angle with a 5/8” drill bit may cause spalling and damage to the surface above the drilled angle as the outward heave force from the passage of the drill is greater than the strength of the concrete at that location, resulting in concrete spall and cracking damage at that location.  For these applications, Alchemy-Spetec offers 5/16” (8mm) and 3/8” (10mm) diameter packers (see FIGURE 1).  

   The smaller cross section of drilling produces much less heave force against the face of the concrete and offers much better results when drilling into a thin concrete substrate. 

   Post-tension structures and/or structures with a significant amount of rebar also present an obstacle when drilling.  By reducing the size of the drill bit by 40-50%, the contractor also decreases the probability of drilling into rebar or post-tensioning accordingly.

2. The tradeoff for smaller diameter is a decrease in pressure tolerances.  Common ½” (13mm) or 5/8” (16mm) mechanical packers tolerate spikes in pressure greater than 4,000psi (see FIGURE 2).  At 4,000psi, packers and ports can present a significant job-site hazard as they can exit the drill hole at dangerous velocities.  While injecting at these pressures are never recommended, a ½” (13mm) or 5/8” (16mm) rubber base on the mechanical packer will prevent blow-out significantly better than the 5/16” (8mm) or 3/8” (10mm) counterpart.

Mechanical packers and ports are used on almost every leak seal chemical injection project. If a contractor is using chemical grout, then there is a high chance that they are also using mechanical packers. Considering that leak-seal injections are often performed in small cracks and joints, the mechanical packer portion of the project is often more significant than the chemical grout. Let’s begin with a brief overview of packer terminology as reference.

Several suppliers offer 2-3 standard mechanical packers and ports assuming that these are generic in design and commoditized. This assumption is incorrect. Not all mechanical ports are created equal, and we aim to define these functional differences in this brochure. Mechanical packers are most commonly defined by four key aspects; and these are Diameter, Length, Type, and Ball-Valve Location. Over the next few blog posts, we’ll examine the functional differences of these key aspects.

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The North American Tunneling Conference (NAT) is the premier tunneling event for North America, bringing together the brightest, most resourceful and innovative minds in the tunneling and underground construction industry.

Here are 5 reasons to visit Alchemy-Spetec at NAT 2018:

1. LEARN more about our Leak Seal and Geotechnical chemical grouting product offerings. 
2. DISCUSS our comprehensive chemical grout training school coming in September.
3. EDUCATE yourself on our injectable and hydrophilic polymer waterstop systems for precast segments and walls.
4. SCHEDULE one of our experienced field technicians for a site visit.
5. PLAY with expanding foams and gels to get a sense of how these products work.  

• Monday June 25th:  5pm - 7pm (Opening Reception)
• Tuesday June 26th:  11am - 2pm, 4pm - 6pm
• Wednesday June 27th:  9am - 12 Noon.

Alchemy-Spetec will be in booth #659 in the floorplan linked below: 

NAT 2018 Interactive Floorplan

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The Alchemy-Spetec R-ITS system is a re-injectable system for acrylic resins and combination grouting with microfine cements. It can also be used as a standard single-use injectable tube system with polyurethane
resins and foams. Due to the specialty nature of this system, it is not sold in kits.

Ordering details are outlined below (and in our price list)...

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The Alchemy-Spetec Gel Pump is a pneumatically-operated, high pressure, stainless steel, dual-component chemical injection machine designed primarily for low viscosity acrylic gels like Spetec AG100 and Spetec AG200.  A third component, or flushing agent, is pumped through an additional piston assembly that is operated at the mixing manifold.  

Advantages:

• Stainless steel design suitable for acrylic oxidizing agents
• Convenient pneumatic operation
• Portable machine able to be picked up
• Wheeled cart design for easy mobility
• Complete hose sets and applicator
• Single air drive runs both pistons to maintain true ratio
• Able to produce >2000psi of output pressure

Field of Application:

• Acrylic gels
• Low-viscosity, 1:1 chemical resins
• Combination grouting of microfine cements and polyacrylate gels

Click here to download the Gel Pump datasheet for more info.

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The Alchemy-Spetec Drill Pump is a high pressure, single-component chemical injection pump suitable for low to mid viscosity chemical injection grouts. It’s most commonly used for the application of polyurethane injection grouts. The drill-mounted design offers a convenient and portable solution for chemical injection applications.

The Drill Pump offers an unmatched ease of access to the piston assembly and ball/springs through just a few allen screws. The small reservoir and direct-feed design allows for small batch mixing and eliminates excessive losses due to mixing and priming. The portable design (20lbs with drill) provides a unique and high pressure solution that can easily be carried onto swing stages, scaffolding or scissor lifts.

Click here to download the Drill Pump datasheet for more info.

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The Dynamic Cone Penetrometer allows you to perform continuous dynamic penetrometric tests. The fact that it is exceptionally small means you can use it on sites that are inaccessible to normal machines. A hydraulic extractor is used to extract rods, casing tubes and samplers. The penetrometer is controlled via a pedal-operated distributor. The hydraulic connections on the various components use quick connectors. Its reliability is proven by hundreds of units operational around the world.

The penetrometer is equipped with a 66 pound (30 kg) hammer with a 7.87 inch (200 mm) stroke, operated by a hydraulic motor. It is driven by a motor-pump unit (the motor can be either electric or a gasoline engine).

The Dynamic Cone Penetrometer can be used not only for dynamic tests, but also for soil sampling with limited disturbance, which guarantees improved ability to interpret the penetrometric data.

Click here to download Dynamic Cone Penetrometer datasheet for more info!

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