Pressure Transmitter

    Pressure Transmitter
    Pressure transmitters are a common and well understood 

technology especially within the petroleum, petrochemical, refrigeration and fuel gas markets and they are extremely 

economical compared to other technologies.

    Pressure transmitters are a common and well understood technology especially within the 

petroleum, petrochemical, refrigeration and fuel gas markets and they are extremely economical compared to other 

technologies. If a level is to be made in an open vessel a pressure transmitter (PT) is placed at the bottom and the head 

pressure caused by the weight of the liquid can be used to calculate the height of the liquid. Differential pressure 

transmitters can be used on pressurised vessels using the same principles (9).

    Level measurement using pressure transmitters cannot be deployed in primary separators as the change in temperature 

will impact the measurement, the change in density of the oil during operation will impact the measurement and any 

fluctuation of the oil/gas differential pressure control valve or pressure disturbances would also impact on the 

reading.

    Portable dP gauges are used to monitor the dP across strainers, online densitometers, DB&B valves, prover interchange 

valves, and other devices. All pressure gauges shall be equipped with calibration stickers indicating the last test or 

calibration date and who performed the calibration. The calibration sticker should be clearly visible and constructed of a 

rugged material. All recordings on the sticker should be made with indelible ink. The dial gauge cover should be 

clear and abrasive resistant. The pressure gauge should be readable with permanent figures and markings and equipped with a 

blowout disc for safety. The scale shall be in graduations of no greater than 2 psig with longer graduations at each 5 psig 

and numbered at not greater than 10 psig intervals. The error at any point on the scale should not exceed ±2 psig. The 

maximum allowable working pressure (MAWP) of the dP gauge should be at least equal to the MAWP for the measurement 

facility.

    A differential pressure 

transmitter is a device that translates physical force to an electrical signal. The most common type of force 

transducer uses a diaphragm, piston, bourdon tube, or bellows to sense the physical force and various strain/force-sensing 

devices to convert the deflection of the physical element to an electrical signal. Traditional strain-sensing devices 

include the following: capacitive cells, piezoresistive strain gauges, piezoelectric quartz material, and electromagnetic 

devices.

    In the United States, companies such as Rosemount, Cameron/Barton, Foxboro, and Ultrasystems have provided transmitters 

that specialize in safety system pressure measurements. These transmitters may still function successfully on some iPWR 

designs, but many will have to be reengineered for different mounting configurations, size constraints, and environments. 

Many iPWR designers, when faced with a modification program, may choose to go with new technologies rather than modifying 

the old ones. The new technologies may offer advantages in size, redundancy, accuracy, and environmental resilience. Some 

of these new technologies include microelectromechanical system (MEMS) sensors, fiber optic sensors, and ultrasonic 

sensors.

    In the optical fiber category, a company called Luna Innovations has developed and successfully tested fiber optic 

pressure sensors, like the one shown in Fig. 6.1, in a research reactor environment. These fiber optic pressure 

sensors have been shown to operate in radiation environments with flux levels much higher than those compatible with most 

electronic pressure sensors. With traditional technology, it is necessary to protect traditional electronic 

gauge pressure transmitter from harsh 

radiation conditions near the core; this requires the use of long pressure sensing lines, which limit the response time to 

pressure transients and increase the number of wall penetrations. Luna’s fiber optic pressure sensors are designed to 

operate in harsh environments. When these pressure sensors were combined with Etalon-based fiber optic temperature sensors 

providing temperature compensation, drift effects were minimized. The attractiveness of this technology for iPWRs is 

obvious, with the elimination of sensing lines, the minimization of penetrations, the small size of the sensor, the rapid 

response to pressure fluctuations, and the operability in high radiation fields. With these attributes, this technology 

bears merit for primary and secondary side pressure measurement (Dickerson et al., 2009).

    Pressure or DPT transmitters have been used to measure liquid levels of open or pressurized tanks, respectively, 

with proper calibration taking care of the density value of the subject liquid. These types are used for level measurements 

of boiler drums, all heaters, deaerators, condenser hotwells, condenser surge tanks, and all dosing tanks.

    For open tanks, a pressure tapping at a suitable location is connected through the impulse line, to the high-pressure 

port of the DPT with the low-pressure port open to atmosphere. The pressure (or DP) sensed by the DPT is proportional to 

the level with a known liquid density (ρ) and force due to (earth’s) gravity (g). With proper calibration, the potential 

transform can now be used as a level transmitter.

    Regarding the pressurized tank or vessel, single-pressure tapping does not serve this purpose as it senses 

the pressure of the vessel and the pressure of the liquid level. To balance out the vessel pressure, another pressure 

tapping for sensing it is connected, through the impulse line, to the low-pressure port of a DPT so that the output will 

only be proportional to the liquid level only with known ρ and g.

    Another new technology for pressure sensing is the polymer-derived ceramic MEMS sensor. At the forefront of this 

technology, a company, Sporian Microsystems, has developed a pressure/temperature sensor made to survive high temperatures 

(Fig. 6.2). This technology offers a solution for pressure sensing in iPWRs due to its hardy environment survivability and 

its small size. The small size allows for the installation of redundant units and the measurement of pressure at many 

points, possibly with fewer penetrations than traditional sensors.

    These new technologies have attributes like small size, heat survivability, radiation hardness, fast response, and low 

maintenance. These attributes are highly valued in iPWR designs for obvious reasons.
                
     The Series-211 differential 

absolute pressure transmitter can accurately measure positive, negative or differential pressure and send the 

corresponding 4–20 mA output signal to a recording system. It is not position sensitive and can be mounted in any 

orientation without compromising accuracy. It also features a power LED, so one always knows when the transmitter is 

operating. The compact, light-weight design makes installation simple and easy. Two inlets for the pressure connections are 

located on the front of the unit, labeled “High” and “Low”. For differential pressure measurement, the higher pressure 

should be connected to the “High” pressure port. For positive pressure, the “Low” pressure port should be left vented 

to atmospheric pressure. Periodically, it is necessary to recalibrate the gauge to maintain the accuracy. For “zero” 

gauge, the pressure connection needs to be removed from both pressure ports and to adjust the zero potentiometer until the 

output is 4 mA. To span the gauge, the full scale pressure to be applied to “High” pressure port and to adjust the 

span potentiometer until the output is 20 mA. The salient features of the pressure transmitter are compact 

design, LED power indication, 2-wire design, 4–20 mA output, ± 0.25% accuracy level, 0–90 mmHg pressure range, 

–25 °C to 70 °C operating temperature ranges, 2-wire output signal and 12–30 VDC power supply.
                
    Drum level is measured by differential [url=http://www.onlysft.com/temperature-transmitter/thermal-resistance-

temperature-transmitter/]thermowell temperature transmitter[/url] installed in line with Figures XII/3.5-1(a,b). Note that 

for drum-level measurement a temperature-equalizing column has been used to ensure that in both limbs of DPTs temperatures 

are equal, meaning that the densities are equal. So far, the discussion has been about installation and making the two 

limbs’ temperatures equal. Now level is measured by because there is an incumbent pressure P1 at the top, which 

needs to be subtracted to get the level. So, finally, one is left with P1 at the top and P1 + pressure 

due to water head (P) on the other limb. Therefore DP = pressure due to water head, P = h × ρ × g.
                
   For a particular place, g is always constant. So water head P varies with h (level) and 

density, which in turn depends on temperature. In the drum, incumbent pressure is due to saturated steam pressure, and for 

saturated steam for each pressure there is a particular temperature. Therefore, saturation pressure is chosen to 

compensate/correct the density effect. Temperature is a sluggish parameter, so pressure is chosen to compensate.
                
    Degradation of the transmitter’s accuracy and response time (two uncorrelated phenomena) are the two most important 

consequences of ageing. Ageing caused by heat and humidity can cause the transmitter sealing materials to fail, allowing 

moisture to enter the transmitter housing. This can cause calibration shifts and high-frequency noise at the transmitter’s 

output, which can render the transmitter inoperable or unreliable. Though NPP I&C failure data indicates that calibration 

drift accounts for anywhere from 59% to 77% of all age-related failure in pressure transmitters (fow blockage, fatigue, and 

other factors accounting for the remaining age-related failures), a survey of the nuclear industry in the early 1990s 

showed that fewer than 10% of NPP pressure transmitters actually drift out of tolerance and that in a typical two-year 

fuel cycle only about 1–3% of transmitters suffer calibration failure.
                
    The analog signal operates over a 4–20 mA range (0 to 5 Vdc with a 250 Ω high-precision pull-up resistor). 

For proper analog signal discrimination, the tertiary device should be equipped with at least a 12-bit ADC converter. 

Digital signals are preferred over analog signals for accuracy. However, the tertiary device must be able to communicate 

with the secondary devices using a common communications protocol. The status signals typically are used for 

indicating block valve status (fully open, fully closed, in travel), generating commands to obtain a sample 

(activation of sample extractor), and alarm status.
                
    The transmitters should be equipped with a display of the current readings at the transmitter housing in appropriate 

engineering units. The transmitters should be equipped with both analog and digital output to the tertiary 

device.
                
    For analog communications to the tertiary device, a 4–20 mA signal is preferred and requires a high-

precision 250 Ω pull-up resistor (to convert from 0 to 5 Vdc). The dampening parameters should be turned off or set to its 

lower limit. For digital communications to the tertiary device, the update interval of the transmitter should be less than 

or equal to 1 second. The transmitters should be equipped with an appropriate communications protocol and the dampening 

parameters should be turned off or set to its lower limit.
                
    The sensing lines that bring the pressure signals from the process to the transmitter can become partially or totally 

blocked due to sludge, boron solidification (PWRs), and other debris in the reactor coolant, causing sluggish dynamic 

performance in the transmitter. According to NRC data, blockages, voids, and leaks account for nearly 70% of the age-

related problems in sensing lines. Nevertheless, the effects of ageing on response time are even less significant than the 

effects on calibration. The response times of 84% of transmitters tested in a 1994 study written by the author for Nuclear 

safety were unaffected by ageing. Of the remainder, only 4% delivered response times that could be considered failing.

The Best Razors, According to Barbers

    The Best Razors, According to Barbers
    Getting the best shave comes down to having the best tools for the job. You’ll want to use a 

good shaving cream, of course, but the most important thing is to choose the right 

men's razor. A cartridge razor with disposable blades is the method 

most men learn first (and stick to), and replacement blades are available pretty much anywhere. An electric 

razor might be best for someone who wants to be as quick and efficient as possible. There are also safety razors, 

which have been around for more than 100 years and have recently surged in popularity because many feel they provide a 

better shave — plus, they’re more eco-friendly and economical. And there are straight razors, which are typically 

the domain of professionals, but may also appeal to passionate shavers because of the unique control they offer. The fact 

that countless different brands make different models of the same type of razor can make choosing the right one even more 

overwhelming.

    To help folks find the best razors on the market, we asked 14 men’s-grooming experts — including ten barbers — about 

their favorites and combed through our archives to find other worthy options recommended to us before. The resulting 

selection of razors (below) features a style for pretty much everyone, [/b]including cartridge, electric, and safety 

razors, along with hybrid styles, and razors to use on sensitive skin. No matter which style of razor you choose, Tony 

DeAngelis, a co-owner of Blue&Black barbershop in Carroll Gardens, says there are two other important factors for 

getting a good shave: heat and stretching the skin. As he explains, “heat, whether from running the shower or the sink, 

allows hair to come off easier, which means less irritation. And stretching the skin while you shave means fewer chances of 

nicks and scratches, because you’re creating a tighter, smoother surface for the blade to move across.”

    Even though cartridge single blade razor for 

men may be the most ubiquitous (and what most men learn how to shave with), 12 of the 14 experts we spoke with say 

that a safety razor is actually the best kind to use. The main thing it boils down to is the fact that with a safety razor, 

you’re shaving with only one blade — many of our experts told us that more blades do not necessarily mean a better shave, 

and that using multi-blade cartridges can increase the likelihood of ingrown hairs and razor burn. “The safety razor is 

the absolute way to go,” says Chad Beightol, the owner of New York City–based men’s-grooming store Consigliere. 

“You’re working with a single blade that is sharp, instead of relying on a multi-blade cartridge that is trying to trap 

the hair between the blades.” Paul Langevin of barbershop Mildred New York adds, “The single blade minimizes 

irritation.” Another plus is that safety razor blades (the best of which you can find here) are far less expensive to 

replace than disposable cartridges, and they don’t generate any plastic waste. The experts do admit that, at first, using 

a safety razor won’t be quite as effortless as shaving with a Gilette or Shick (and if you’d rather stick to those 

cartridge razors, there are some on this list, too). But they say most people are quick converts once they get the hang of 

it. We’ve written about safety razors before, and German razor manufacturer Merkur was the brand that came most 

recommended. The Merkur 34C remains our experts’ top pick, with many saying it’s an especially good choice for beginners 

because the short handle makes it easy to maneuver.

    Bevel is a newer safety-razor company that both barber Julien Howard and Beightol recommend. You can purchase 

the twin blade razor for men and blades on 

their own, but they also have subscription options for scheduled blade replacement, along with a full line of 

shaving products. The Bevel razor also has a bit of a sleeker, more contemporary look than the others on this list, and a 

slightly longer and narrower handle that might be more comfortable for some.

    Standard safety razors are pretty straightforward: The head of the razor closes around the flexible metal blade, which 

is then locked into a predetermined angle. This construction works well for most people, but some may benefit from being 

able to customize the angle at which the blade meets the skin. For someone with sensitive skin, a lower angle will allow 

for a gentler shave with less irritation. Someone with coarse facial hair, on the other hand, might prefer a more 

aggressive angle. It all comes down to personal preference, and that’s why Xavier Rodriguez of Fellow Barber and 

Peter Solomon of Tweed Barbers of Boston both recommend the adjustable Merkur Progress to anyone who thinks their 

safety-razor shave might benefit from some customization. It has five different blade-angle settings, and you simply twist 

the dial at the bottom to toggle between them. If you decide this is the razor for you, you’ll want to get some 

blades for it as well.

    Mike Gilman, the owner of the Grooming Lounge, agrees that a safety razor is going to provide the best shave when used 

properly. But he also notes that using one may simply not be practical for everyone. You need to be a bit more careful with 

a safety razor, so it’s going to take a little longer to shave; you also need to devote some time to learning proper 

technique. “For most guys, the method of shaving that works best, and that they are most used to, is shaving with a 

cartridge razor. The blades and razors are available everywhere, and they’re super-easy to use.” If you want to go the 

cartridge-razor route, Gilman says it’s wise to stick with a classic. His pick, the Gillette Mach 3, uses a three-blade 

cartridge, which is a nice compromise between the single blade of a safety razor and the five blades of some of the newest 

cartridge razors. [/b]“I just think the Mach 3 is the way to go,” he says.

    Langevin agrees with Gilman that a cartridge razor would be a better choice for “people who don’t want to master 

shaving with a safety razor.” He likes Harry’s, however, which he says makes a good “disposable-blade system.” Like 

Bevel’s razors, Harry’s razors and blades are available à la carte, but you can also sign up for a subscription blade-

replacement plan through the brand’s website.

    Editor’s note[/i]: While Amazon sells the women's razor with 

two blade refills, if purchased from Harry’s, you’ll only get the razor, hence the cheaper price.

    Groomer and makeup artist Robert Reyes says that while “safety razors are great for sensitive skin, they can 

be a bit time-consuming.” So if you’ve got sensitive skin but prefer a cartridge razor, he suggests this Schick model 

that he personally uses. “It has lubricated skin guards that help protect the skin,” Reyes explains.

    For the fastest and easiest shave, an electric [url=http://www.goodmaxrazor.com/womens-razor/triple-blade-razor-

for-women/]triple blade razor for women[/url] will likely be the best bet, and some of our experts say that using one 

can also reduce the occurrence of ingrown hairs. “For those who don’t like the traditional methods, I recommend foil 

shavers,” says Langevin. Foil shavers have a thin perforated sheet of metal covering the blades; individual hairs are fed 

through the tiny holes and cut by the blade below. According to Langevin, the resulting shave is the closest you can get 

with an electric style, and comparable to that of an analog razor. “Foil shavers get almost as close as a traditional 

razor, sometimes even closer,” he adds. Langevin, barber Karac Ruleau of Mott NYC, and Heather Manto of 

Austin’s Independence Barber Co. all recommend the Andis Cordless Profoil Shaver — Langevin uses the Andis 17200 and 

Manto and Ruleau [/b]use the slightly older 17150, but they are essentially the same. (The Andis Profoil, perhaps not 

surprisingly, also appears on our list of the best electric razors). The shaver is designed with commercial use in 

mind, but Manto says she would recommend it for home use as well. “It helps to pull out ingrown hairs, doesn’t cause 

razor bumps, and can be used wet or dry,” she says. Adds Ruleau: “It gives you a super-close shave without any razor 

burn, is light, durable, and inexpensive, and doesn’t require a frequent charge.” But one note from all of our experts: 

Foil shavers like this aren’t designed to cut long hair and only work on short, “stubble length” facial hair. While that 

might seem limiting, Manto thinks it makes them a great choice for people who shave regularly.

    If you’re looking for an electric option to tackle longer hair (or use on sensitive skin), four experts have told 

us that Wahl’s Peanut is the best because it has a powerful motor, is easy to maneuver, and comes with four guards 

that will help you achieve the exact facial-hair length you want. (The Peanut, according to even more experts, is also 

great for shaving your head and manscaping.) DeAngelis calls it a “compact, sturdy machine that is going to 

cut what you need it to cut, but still allow you to work safely around your mustache and lips.” If used without those 

guards, the trimmer will cut facial hair down to that coveted five-o’clock-shadow length, add the pros, who note that a 

trimmer like this is also the best style of electric razor for people with sensitive skin (because of the fact that it 

doesn’t cut so close results in less irritation). While Wahl also sells a cordless version of the Peanut, most 

of our barbers prefer the corded style because they say it offers more consistent power.

    Marissa Machado, a celebrity groomer and makeup artist, and two regular guys — Strategist contributor Kurt 

Soller and New Scientist[/i] editor Conrad Quilty-Harper — like the OneBlade electric razor from 

Philips Norelco, another classic brand. The OneBlade uses cartridges that are meant to be replaced every four months and is 

shaped like a more maneuverable cartridge razor, but it’s battery powered and features a vibrating blade, so it also 

recalls electric styles. Machado says that “it gives a smooth finish” and, unlike other electric razors, it’s designed 

to “be used with or without shaving cream

.” She also praises its customizability: “It comes with trimming attachments, so it’s really an all-in-one 

product.”

How to use mica band heater and how does a cartridge heater work


With different electrical termination styles, clamping mechanisms and the ability to accommodate holes and cutouts, mica-

insulated band heaters are used successfully in many applications, particularly 

plastics.

Loss Prevention for Band Heaters

Most band heaters with heating plate do not “burn out”; instead, 

environmental factors create a short, cause hot spots to develop, or simply push the heater beyond its normal operating 

temperature. All of these factors cause a heater to fail prematurely and require replacement. Obviously, minimizing these 

environmental factors can reduce the frequency of replacing band heaters in your operation.

Contamination.[/b]By far, the most frequent culprit of band heater failure 

is contamination. Liquid plastic, hydraulic oil and moisture (often from high ambient humidity) are three main causes of 

premature failure from contamination. Obviously, keeping the heaters free of contaminants will reduce failure and 

replacement rates. In applications where liquid plastic and oil exposure are frequent and difficult to manage, the best 

solution may be to select a low cost band -- the heater will be replaced often, but the financial loss will be minimized. 

Alternatively, a band heater designed to resist contamination can be used. Keep in mind, though, that most heaters fail 

from lead wire damage caused by contamination -- not from contaminants finding their way inside the band -- and 

contaminant-resistant heaters will not prevent lead wire damage.

Poor Contact Between Heater and Barrel.[/b]The second most common cause of premature failure is poor contact between the 

machine barrel and the band heater. A tight fit is critical. Without it, localized hot spots can form on the band and cause 

the resistance wire to fail.

There are two steps you can take to ensure good contact with the machine barrel. First, make sure the machine barrel outer 

diameter (OD) measurement is accurate; then, order band heaters with that same measurement. The heater manufacturer will 

factor in a 0.25" gap, so there is no need to undersize the band’s dimensions.

Second, follow a strict installation and tightening procedure for mica, high watt density or extruded aluminum band 

heaters. Before installation, clean and smooth the machine barrel surface, removing any plastic residue. To install, 

tighten the heater snugly to the barrel using a clamping bolt torque of 10 ft/lb. Next, apply power to the heaters and 

allow them to reach halfway to setpoint temperature or approximately 300°F (149°C). Once at this temperature, cut the 

power and retighten the bands at 10 ft/lb torque. Retightening the band at an elevated temperature will account for the 

heater’s thermal expansion. (Remember, ceramic band heater

s are radiant heaters and should not be tighten in this manner.)

Handling Procedures.[/b]Often, failing to understand a heater’s internal design leads to heater losses. For instance, 

stretching a one-piece mica band over a barrel during installation can damage the internal mica, resulting in a short 

circuit. Some manufacturers offer band heaters similar to mica bands that can be stretched for installation, but using 

installation techniques inappropriate for a specific heater type will cause problems. So, in cases where one heater design 

will not work -- for example, a machine setup that requires stretching the band over the end of the machine barrel, which 

would damage a mica band heater -- use a heater that is 

better suited to application such as a two-piece mica or a one-piece expandable band. A two-piece design also is a good 

choice when a large diameter band is required as the design minimizes the chance that air gaps will develop. Two-piece 

ceramic bands also can be used on large diameter barrels.

Another simple handling tip is to use two wrenches to install the wiring onto the band’s post terminations. This practice 

can eliminate failures because the wrench on the post’s lower nut acts as a strain relief. If this procedure is not 

followed, the post’s internal connection to the resistance wire can be damaged and become a weak link within the heater.

Runaway Temperatures.[/b]Heaters, like finned heaters, 

are extremely obedient entities. If a controller tells them to produce temperatures beyond their limitations, they will do 

so -- until their demise. Runaway temperature commands often occur when the thermocouple or RTD does not make solid contact 

with the surface measured. If the sensor becomes loose or disconnected from the surface, its readings may be hundreds of 

degrees lower than the process or barrel’s actual temperature. This faulty input then is received by the control device, 

which calls for full output from the heaters when in fact the process is already up to appropriate temperature.

Given the range of products plant maintenance and engineering personnel encounter, is not realistic for them to become 

experts on every piece of equipment used. This article only touches the surface of band heater design, options, performance 

expectations and loss prevention. Users should link up with a qualified supplier that can help design a new system or 

perform a design analysis on an existing system, then make recommendations to ensure the best performance for the given 

application. Systems arising from a good supplier/user partnership will extend equipment life and allow critical production 

schedules to be reached.

Sidebar: Understanding Watt Density Calculations

When designing a system, it is a good idea to match the total wattage applied to the actual wattage required. This practice 

decreases cycling frequency and temperature overshoots while increasing the heater’s life span. When possible, it also is 

good practice to specify strap-style clamping devices to hold the heater in place. These devices have a lower thermal 

expansion rate than the heater, so they can help hold the heater, or the [url=http://www.cnheaters.com/heating-

element/defrost-heater/]defrost heater[/url], tightly against the barrel during operation.

The durability and performance of a heater depends on selecting the appropriate wattage by using 

resistance thermometer. Exceeding the maximum allowable watt 

density for the specified heater size will result in premature heater failure. While calculating watt densities, remove the 

area of the cold section form the overall calculated surface area of the heater.

Watt Density (W/in2) = Wattage / (3.14 x Inner Diameter x Width) - (Cold Section)

Other points to consider while selecting watt density include:

The watt density should be selected in accordance with the operating temperature.

To avoid short cycling and inefficient operation, select a wattage as close to the needed capacity as possible.

The wattage should be in accordance with the voltage and current rating of the controls.

The safe heating pattern,and heating elelment of the material heated, 

thermal conductivity and coefficient of expansion of the cylinder are other factors that should be taken into consideration 

while deciding wattage.

A cartridge heater is a tube-shaped, industrial heating element that can be inserted into drilled holes. Cartridge heaters 

provide localized and precise heating and are commonly used in the heating process industry. Typically, cartridge heaters 

are used to heat a metal block from the inside and can be custom manufactured to a specific watt density based on the 

requirements of the application.

Cartridge heaters are most frequently used for heating metal parts by insertion into drilled holes. For easy installation, 

the heaters are made slightly undersize relative to their nominal diameter.

How does a Cartridge Heater work?

A cartridge heater consists of resistance coil wound 

around a ceramic core that is surround by dielectric and encased in a metal sheath. Powered heat transferred through the 

coil to the sheath causes the sheath to heat up. This heat is then transferred to the inside metal part requiring heat.

To fit a cartridge heater in a low or medium temperature application (600°F or less), general purpose drills are usually 

adequate for drilling holes. Holes can be drilled .003” to .008” over the nominal size of the drill, resulting in fits of 

.009” to .014.” While this fit is slightly looser than would permit optimal heat transfer, it aids in the installation 

and removal of the cartridge heaters with heating cable, especially 

those with long sheaths. At high watt densities, a close fit is much more important. The holes should be drilled and reamed 

rather than just drilled with a general purpose bit. With a tighter fit, the heater will run cooler and have a longer life 

expectancy.

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Threaded Rod – Everything You Need To Know

    What is threaded rod?

    Threaded rod, often referred to as a stud, is a rod of varying length that is threaded in a helical structure.

    Similar in appearance to a screw, the threading extends around and along the rod to cause rotational movements when in use. Threaded rods combine linear and rotational movement to create strong resistance to pressure.

    The direction of the rotation caused by a full threaded rod depends on whether the rod has a right-hand thread, left-hand thread, or both.

    Designed to withstand very high levels of pressure and tension, threaded rods are a common fixing for support systems and used for a variety of applications.

    What is a threaded rod used for?

    Threaded rods are fasteners and functions thanks to the threading, which causes a tightening action from the rotational movement. Threading on a rod allows other fixings like bolts and nuts to easily screw or fasten to it.

    Threaded rods have many applications, effectively working as a pin to fasten or connect two materials together.

    Also used to stabilize structures, they can be inserted into various materials like concrete, wood or metal to either temporarily create a steady base during construction or they can be installed permanently.

    How to choose the correct threaded rod

    There are several types of threaded rod available on the market that will suit different purposes, conditions and materials.

    The fully threaded rod that Armafix supplies are usually used when effective grip strength is required through the entire length of the rod.

    They are often used to align structures or are embedded into materials, like concrete, as the threading provides good resistance.

    The material is another essential factor to consider when choosing the best-suited rod for your application.

    Threaded rods are used in a variety of sectors and for several purposes such as construction, plumbing, manufacturing, marine, agricultural, oil extraction and contractor work.

    How to cut threaded rod

    Sometimes threaded rod will have to be cut to suit your project. It is a common question and not quite as simple as you might think. The rod can be difficult to hold in place and the threading can be affected.

    Perhaps the easiest and more efficient way of cutting threaded rod is to use a rod cutter, which will produce a clean, burr-free cut with less effort and less time wasted, plus it is lightweight and can be used for overhead work.

    Cutting threaded rod with a hacksaw

    If you’re using a hacksaw, a good tip is to take a small block of wood and drill a hole through it to place your rod through.

    Secure the rod in the vice with two nuts either side using a thin kerf, the rod can then be cut and held in place. Once it is cut, you can unscrew the nuts, which will tidy up the ends and keep the threading in good shape.

    A simple illustration of this can be found here.

    Another efficient method is to use a bench vice to hold the rod in place, and an angle grinder to cut the rod. Cut the road at a flat angle and be sure to wait a few minutes before touching the newly cut edge after using an angle grinder as it will be hot.

    How to bend threaded rod

    As well as cutting threaded rod, sometimes it needs to be bent in order to fit the intended application. This involves using a mounted bench vice and propane or Oxy-Acetylene torch and should be done with caution.

    Placing two bolts in the vice again to clamp around the rod, fix the threaded rod securely in place. Apply the lighted torch on the part of the rod you wish to bend.

    Metal can be damaged by too much heat, but for stainless steel – as a general rule of thumb – once it is a reddish colour, it is ready to bend. You can reheat the rod several times until you have the required shape.

    Remember to use heavy-duty gloves and eye goggles!

    How to join threaded rod

    If you need to connect threaded rods, you can use connector bolts to get the required length and secure them together.

    You can also use threaded rod plastic protection caps to cover and protect the ends.

    The welded washers are usually there for shear (tension wouldn't require the weld EDIT: IT WOULD REQUIRE THE WASHER, THOUGH). If you have adequate friction resistance or shear keys under the baseplate, you don't need welded washers. If you designed the connection to resist lateral loads through shear in the bolts, it depends. If you designed for 2 of the 6 bolts (I'm guessing at your layout) to take all of the shears, you probably don't need the welded washers as long as your ok with movement of the base of the column equal to the diameter of the oversized hole (again, assuming it's oversized) minus the anchor diameter (Not half, but all - what if the anchor is slightly off and hard against the opposite side of the hole? There's a reason oversized holes are used in baseplates.) If you need all of the bolts to resist the shear, then you need to have welded washers at all of the bolts. If you don't, you could have a couple bolts closer to the sides of the holes than others, so they'll load first and prevent the others from loading until they have deflected and/or failed - and then the others engage with two fewer than needed and the rest fail.

Whole Herbs vs. Standardized Herbal Extracts: Which is Better?

    Many Herbal Products to Choose From

    The mainstream use of herbal medicines is becoming increasingly popular, and there are many herbal products to choose from. With so many choices, it is easy to get confused about which forms of herbs are right for you. One important decision is whether to use whole herbs or standardized herbal extracts. This can be tricky because even the experts are split on this issue. Therefore, it is best to know the facts about the difference between the two so that you can make an informed decision.

    Whole Herbs

    A whole herb is just what it says: the whole herb, usually dried and encapsulated or processed and preserved in alcohol or another solvent. Whole herbs contain all of the constituents of the plant and have been used for hundreds of years by many cultures. In fact, modern medicine originated with the use of whole herbs. The medicinal properties of herbs have been learned through empirical observation and the information has been passed down through successive generations of healers. Although the effects of herbs have not always been formally and scientifically researched, whole herbs have a long track record validating their safety and efficacy.

    The chemical makeup of an herb can vary slightly, however, depending on a variety of factors. First, the environment in which the plant has been grown has an effect on the constituents of the herb. The time of year it is harvested, the soil in which it is grown, and the weather all influence the overall quality of the final product. Second, methodology plays a role. For example, the age of the plant at harvest, the exact part of the plant being used, and processing techniques can all make a difference. Finally, each plant or population of plants has its own individual genetics, thus adding another source of end-product variation.

    Standardized Herbal Extract

    Standardized herbal extracts are functional ingredients that have one or more components present in a specific, guaranteed amount, usually expressed as a percentage. The intention behind the standardization of herbs is to guarantee that the consumer is getting a product in which the chemistry is consistent from batch to batch. This practice has developed out of the drug model of herbal medicine, in which modern scientists have attempted to identify the components of a plant that have definite pharmacological activity in the body. Unfortunately, while scientists can isolate many constituents from an herb and discover how particular chemicals may act in the body, they inadvertently remove or overlook components that may contribute to the activity of the whole herb. Consequently, standardization may concentrate one constituent at the expense of other potentially important ones, while changing the natural balance of the herb’s components.

    As more shoppers gravitate toward fresh foods in lieu of processed items, bakers must examine how their products align with this changing attitude. According to the U.S. Department of Agriculture, Americans are consuming more products than ever, but the average U.S. diet still falls short of the recommendations listed in the 2015-2020 Dietary Guidelines for Americans due to lack of access, busy schedules, poor eating habits and more.

    While nothing may ever completely replace the feeling of biting into a crisp apple or the smug satisfaction of finishing a salad, fruit and vegetable powders give snack producers an opportunity to provide consumers with nutrient-dense products that can be conveniently enjoyed without the intense prep work other fresh items require.

    ON THE FACE OR body, a dusting of powder gives a smooth finish to the skin, covers blemishes and flaws, and absorbs perspiration and excess skin oil.

    The marketplace offers a profusion of powders. There are matte face powders, in loose or pressed form, that are designed for dry, normal or oily skin; translucent powders that allow the natural skin color to show through; opalescent powders that give the skin a slight shimmer; tinted powders that tone down ruddiness; body powders that are suffused with fragrance or with glitter for nighttime sparkle; baby powders that are made from either talc or cornstarch; medicated powders that fight body odor and troublesome microorganisms or soothe irritations, and even perfumed liquid body ''coolers'' - powder suspended in an alcohol base - that dry on the skin to a powder finish.

    The highly purified powders of the present are a far cry from the crude cosmetics of the past. From the dawn of history, vanity led women to sometimes life-threatening lengths to whiten their skin. The earliest powders were concocted from ingredients such as bean flour, chalk and ceruse, a highly toxic white lead. 

    Today, most powders are a blend of several cosmetics ingredients, including talc, zinc oxide, titanium dioxide, kaolin and magnesium carbonate, each of which imparts specific benefits. According to cosmetic chemists, the ideal powders should have five characteristics: covering power, absorbency, adhesiveness, slip and bloom.

    There’s a lot of buzz around probiotics. They’re endorsed by celebrities and fill grocery stores aisles.

    Probiotic powder is beneficial bacteria that promote a healthy gut. Scientists believe they could unlock a deeper understanding of our health. Probiotics are found in some foods and drinks, like yogurt or fermented tea. 

    Just like vitamins, probiotics are available as supplements. Manufacturers make steep claims about their benefits. They include digestive health, strengthened immune system, weight loss and reduced cancer risk.

Reducing the risk of wound infections with disposable surgical clothing

    To minimize the risk of germ transfer in surgical operating theatres, sterile draping of patients, their surroundings and the wearing of sterile clothing are all essential safety measures, irrespective of the nature of the operation. Given their vital role in infection protection, draping materials and operating theatre clothing are legally regarded as medical products with their production and quality testing subject to European Standard EN 13795.

    Reducing the risk of wound infections with disposable surgical clothing

    Different operations have different risks of infection. Long, complex operations involving high levels of blood and irrigating fluids, carry the highest risk while risk is lower, but still present, in shorter operations where large amounts of body fluids are not expected. Even with careful observance of hygiene standards, and execution of the usual antibiotic prophylaxis, there is infection at the surgical site in approx. 1-5 % of elective surgical procedures. For the patients affected, this means an extension of their pain and functional restrictions – even if there are no more serious consequences.

    Single use vs. Reusable Materials

    The material used in surgical drapes and sterile clothing also raises issues of health economics. Draping materials and operating theatre clothing made of nonwoven fabric are often preferred to reusable textile systems due to the material safety and the associated high level of protection against infection. Although these are the most important reasons, another benefit is that single-use materials remove the need for sophisticated reprocessing of reusable textile systems, which is a cost-intensive undertaking.

    Medical products are classified into two performance levels: high performance and standard performance. This means that draping materials and 68g original-spunlace nonwoven surgical gowns can be tailored exactly to the respective surgery-specific requirements in material quality and product design. This flexibility allows hospitals to choose safe, cost-effective standard performance speciality medical drapes for low-risk operations and specific tailored surgical gowns for higher-risk operations involving large amounts of body fluids.

    Single-use and reusable products are subject to the same safety standards as applied to reusable products for their entire life cycle. 

    The minor procedure sets contain a large assortment of instruments. All tools are manufactured of high-quality nonwoven and are contained in a durable canvas case.

What is a wristlet key fob? 

    Ever had so much character ribbon or just decorative ribbon lying around and wonder what else you could do with it besides making bows?  Well, wristlet key fobs are the perfect way to put that ribbon to use. You can make something fun and creative that you can give out as gifts for family and friends, while only spending a few dollars for all the supplies. Key Fobs are awesome wristlet keychains that you can use to keep track of your keys. They can be simple or as decorative as you like. 

    The devil is in the details when it comes to personal style. That’s why your everyday carry – wallet, pocket knife, etc. – is so important. Elegant details in the form of a dialed-in EDC collection makes a big impact style-wise when going about your day. If you’re looking to upgrade your EDC, we’ve got an easy recommendation: the best leather keychains.

    Keychains are often overlooked, but they’re actually quite useful for keeping your keys organized and keeping your look on-point. In other words, the best leather keychains are like little style easter eggs that streamline your pockets. But top-notch keychains can be hard to find, so we rounded up seven of our favorites below.

    Although we’re all familiar with keychains, there’s actually a decent variety to choose from. Here are a few things to think about while shopping for the best leather keychain.

    We’ve rounded up three kinds of keychains: key fobs, wrist lanyards and key organizers. Key fobs are a sturdy keyring with a decorative leather attachment. Key wrist straps or wrist lanyards are often less stylish than fobs, but up the convenience by allowing you to dangle keys from your wrist while, say, unloading the car. Organizers are very handy, securing keys in a leather pouch.

    The best acrylic keychains are begging to be flashed when handed over to the valet. It’s a fun way to upgrade your everyday look, so go with something that speaks to your personal style.

    Always be sure to check the dimensions of a keychain – especially if you keep your keys in a pocket.

    Sneaker keychains come in very handy when unloading groceries, unlocking multiple doors and simply keeping track of your keys. We like this one from Feelcase because it’s made from a single piece of full-grain leather that feels nice in your palm or on your wrist. You’ve also got 11 leather/claw color combos to choose from, so there should be something for every personal look. It is slightly on the large side, however, at eight inches long.

    The wristlet wallet is an amazing idea that fits perfectly into the concept of creative design and functionality. It is not only an elegant accessory, it is a piece that offers much comfort for those who do not want to leave with a bag. Bags are often a nuisance, especially at concerts and clubs because restrain the hkmenspa of movement. In this way, the wristlet handbag was to create a discrete accessory that can be used as a necklace or bracelet. The difference is a small detail, the piece bringing together a wallet built to keep money, documents and cards. Depending on the model, the accessory has closure with buttons, velcro or zipper.