Pressure in Food Processing

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure in Food Processing

High pressure processing (HPP) is a method of preserving and sterilizing food. Also called high hydrostatic pressure (HHP) processing, pascalization and even bridgmanization, pressures above 400 MPa (58,000 psi) at cold (+ 4°C to 10°C) or ambient temperatures inactivate bacteria, virus, yeasts, molds and parasites present in food. Unlike other food processes that use heat to remove bacteria, the high-pressure, cold pasteurization approach preserves the taste, freshness and texture of food.

Hiperbaric USA - pressure in food processing

In HPP, a food product sealed in its final package inside a vessel is subjected to a high level of isostatic (uniformly applied) pressure from 300–600 MPa (43,500-87,000 psi) transmitted by water.
Source: Hiperbaric USA.

The process is used for a wide range of foods from juices and beverages to fruits and vegetables and meat and seafood products to baby and infant foods, dairy products and more.

Comments/Questions?
Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at info@allsensors.com

Pop goes the Chip Bag

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pop goes the Chip Bag

Transitioning from lower altitude to a higher altitude decreases the pressure on a sealed container. Normally this would be recognized by the bloated appearance of the product in a sealed bag and a rapid release of the pressurized air inside when the bag is opened.  However, if the bag’s seal is weak, the bag can explode with a surprisingly load pop, en route.

This occurred recently on a trip where the altitude changed from 1248 feet to 7500 feet. Taking the temperature difference into account, the external air pressure changed from 14.08 psi (97.8 kPa) to 11.25 psi (77.6 kPa). This resulted in the decrease in external pressure of 2.83 psi (20.2 kPa or 78.3 inches of water) – sufficient to explode the weak seal.

Surprisingly, this wasn’t the only time that a bag of the same brand of chips lost its seal during the same trip but previously the bag did not explode. Since several other brand of pretzels and other munchies did not experience a bag failure during many trips, it appears that a little product line pressure testing during packaging is in order to minimize a weak seal.

Air Pressure in a Chip Bag

Comments/Questions?
Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at info@allsensors.com

The Pressure on a Ballerina’s Feet

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

The Pressure on a Ballerina’s Feet

It looks so graceful when a professional ballerina executes classic ballet maneuvers and dances on the tips of her toes in pointe shoes (full relevé) and even hops across the floor. Getting to the graceful level takes a lot of training, practice and stress on the feet, ankles and more. The pressure on various portions of the foot have been the focus of several academic studies, some going back over 35 years or more. It turns out that simply walking in pointe shoes doubles the peak pressures acting on the foot compared to barefoot (860 kPa vs. 410 kPa).

Ballerina in pointe shoes

In one study, published in the Journal of Dance Medicine and Science, pressure data were collected with a high-speed, high-scan pressure platform sampling at 100 Hz. Female dancers in training, approximately 13.5 years old, were the test subjects and measurements were made as the dancers rose from demi-plié to demi pointe (intermediate pressure conditions). The researchers measured pressure and force data for barefoot, soft shoes, demi-pointe shoes and pointe shoes and pressure was recorded for specific areas of the underfoot for each shoe condition. In pointe shoes, the peak pressure is over 3 times the mean barefoot pressure.

Foot Pressure Chart

Another study of dancers in full pointe found that the average pressure on the toe box while on pointe is 220 psi or 1.5 MPa with the majority of the weight (pressure) concentrated on first toe. Even more dramatic results are a 60-kg (132-lb) ballerina landing on pointe from a height of one meter generates an impact force of approximately 4950 N or 700 psi. Its no wonder ballerinas feel they are under a lot of pressure.

Comments/Questions?
Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at info@allsensors.com

Water Cooler Pressures

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Water Cooler Pressures

A water dispenser that cools as well as heats water is a welcome addition in a home or office.  When the replaceable water storage unit is mounted at the bottom of the cabinet, it eliminates the hassle of lifting a heavy container. However, the bottom loader requires pumping water up rather than using gravity to dispense water. Simply transferring water from the bottom of the container to the dispensing valves, a distance of about 4 feet, would require a pump to generate at least 1.7 psi, so a 5-psi pump may be all that is required. Since the unit delivers chilled water, a refrigeration unit is part of the design. The high-pressure side of the compressor is 1.6 Mpa (232 psig) and the low-pressure side is .62 Mpa (90 psig). In contrast, these pressures are considerably lower than an air conditioning compressor such as a Samsung split system/ heat pump that is 3.1 Mpa (448 psig) and 1.6 Mpa (236 psig). It is interesting to note the significant differences in pressures required for a functioning water cooler.

Primo Water Corporation - Bottom Loading Water Cooler

A bottom loading water cooler
Image source: Primo Water Corporation

Comments/Questions?
Do you have a pressure sensing question? Let us know and we’ll address it in an upcoming blog.
Email us at info@allsensors.com