question: why is the fridge door harder to open again right after you’ve closed it? Feels like there is extra suction holding it closed
comment: You are right. When you open the fridge you let hot air into the fridge. When you close it the hot air will cool down which means that the pressure gets lower sucking the door to the frame. There are small vents in the back which will let air into the fridge (these can freeze up with ice and should be checked from time to time). However it takes a bit of time for the pressure in the fridge to equalize. So the fridge door will be sucked into the frame of the fridge for a bit.
passages: In demand valves where the cracking pressure is adjustable by the diver, it may also occur as a result of maladjustment of the cracking pressure (dial a breath) knob. In these cases the freeflow can usually be eliminated by adjusting the setting.
   Section::::Refrigerator mother theory.
   Refrigerator death
  
  A refrigerator death is death by suffocation in a refrigerator or similar appliance such as a freezer. Because, by design, such appliances are air-tight when closed, a person trapped inside will have a limited supply of oxygen. Early refrigerators could only be opened from the outside, making accidental trappings a possibility, particularly of children playing with discarded appliances; several such deaths have been recorded. Modern designs close with a magnetic mechanism that can be opened from the inside, reducing the danger of accidental trappings.
  
  Section::::United States.
   In the 1890s gold miners in Australia developed the Coolgardie safe, based on the same principles.
   The number of deaths due to suffocation in refrigerators declined a significant amount in the years after the law. Nevertheless, some deaths have occurred recently. Three children aged 1, 4 and 6 years old died after climbing into an unused freezer/fridge outside of Tallahassee, FL after their mother left them unattended for 20 mins. - Jan 2019. 
  
  Section::::Elsewhere.
  
  Around the world, manufacture of latch refrigerators has been replaced by that of ones with magnet-closing doors.
  
  As recently as 2013, deaths in a latched refrigerator occurred, in South Africa.
  
  Section::::Cultural Impact.
   Crisper drawers which do not have a humidity control are, by default, high humidity crispers.
  
  Section::::Design and operation.:Reported public confusion.
  
  Appliance manufacturers have reported that many refrigerator owners are unaware of the purpose or operation of crisper drawers. A 2010 survey commissioned by Robert Bosch GmbH found that 55 percent of surveyed Americans "admit to not knowing how to use their crisper drawer controls".
   reliably latched. An SEU is "temporally masked" if the erroneous pulse reaches
  
  an output latch, but it does not occur close enough to when the latch is actually triggered to hold.
   In 2000, Russian anti-virus company Kaspersky Lab warned that in few years Internet-connected fridges and other household appliances may be targets of net viruses, such as ones that could be designed to make your fridge door swing open in the middle of the night. In January 2014, the California security firm Proofpoint, Inc. announced that it discovered a large “botnet” which infected an internet-connected refrigerator, as well as other home appliances, and then delivered more than 750,000 malicious emails. In August 2015, security company Pen Test Partners discovered a vulnerability in the internet-connected refrigerator Samsung model RF28HMELBSR that can be exploited to steal Gmail users' login credentials.
   Once the seal is disturbed, the bladder walls instantly spring back to a more rounded shape; the door flies open and a column of water is sucked into the bladder. The animal which touched the lever, if small enough, is inevitably drawn in, and as soon as the trap is filled, the door resumes its closed position—the whole operation being completed in as little as one-hundredth of a second.
   Many newer models of Zipper have solved this problem by completely restructuring the door lock system, also eliminating the need for an R-key. These newer models have also increased the weight of the compartments, reducing the spinning, which decreases pressure on the door latches.
   Section::::External factors influencing bacteria.:Temperature.
   Some kinds of packaging must maintain a seal against the flow of gases, for example, packaging for some foods, pharmaceuticals, chemicals and consumer goods. The term can describe the result of some food preservation practices, such as vacuum packing and canning. Packaging materials include glass, aluminum cans, metal foils, and gas impermeable plastics.
   Where air filled traps are used, these eventually become depleted of their trapped air over a long period through absorption into the water. This can be cured by shutting off the supply, opening taps at the highest and lowest locations to drain the system (thereby restoring air to the traps), and then closing the taps and re-opening the supply.
   Disposal of discarded refrigerators is regulated, often mandating the removal of doors; children playing hide-and-seek have been asphyxiated while hiding inside discarded refrigerators, particularly older models with latching doors. Since 2 August 1956, under U.S. federal law, refrigerator doors are no longer permitted to latch so they cannot be opened from the inside. Modern units use a magnetic door gasket that holds the door sealed but allows it to be pushed open from the inside. This gasket was invented, developed and manufactured by Max Baermann (1903-1984) of Bergisch Gladbach/Germany.
  
  Section::::Types of domestic refrigerators.
   A third problem is where the lower end of the liquid seal is simply a U-trap bend in an outflow pipe. During vigorous emptying, the kinetic motion of the liquid out the outflow can propel too much liquid out, causing a loss of the sealing volume in the outflow trap and loss of the trapped air bubble to maintain intermittent operation.
   Of the electromechanical types, two approaches are used:
  
  BULLET::::- Disengaging – the motor driven mechanism (the opener portion) is not joined to the closer, but only engages the closer when it is needed to open the door. When opening the door manually, the opener portion is still, so the opening is smooth and quiet.
  
  BULLET::::- Permanently engaged – the motor driven mechanism (the opener portion) is always joined to the closer (if present) and to the door. When opening the door manually, the user is also driving the opener portion, so the opening is rough and noisy.
   Belverd Needles
  
  Belverd Needles is an American economist, currently the Ernst & Young Distinguished Professor of Accountancy at DePaul University. He holds a PhD in Accounting (with a Finance and Economics minor) from the University of Illinois at Urbana–Champaign, and Master of Business Administration and Bachelor of Business Administration degrees from Texas Tech University.
   Another variant, uses air, water, and a salt water solution. The intake of warm, moist air is passed through a sprayed solution of salt water. The spray lowers the humidity but does not significantly change the temperature. The less humid, warm air is then passed through an evaporative cooler, consisting of a spray of fresh water, which cools and re-humidifies the air. Humidity is removed from the cooled air with another spray of salt solution, providing the outlet of cool, dry air.
   A model for this is the hinges on a door. When the door is shut, the hinges are flush against the wall. As the door swings open, one side of the door remains pressed against the wall as space opens up on the other side. Removing just a small wedge of bone can "swing" the knee open, pressing the healthy tissue together as space opens up between the femur and tibia on the damaged side so that the arthritic surfaces do not rub against each other.
   The term "occlusion" is used to measure the amount of squeeze. It is either expressed as a percentage of twice the wall thickness, or as an absolute amount of the wall that is squeezed.
  
  Let
  
  Then
  
  The occlusion is typically 10 to 20%, with a higher occlusion for a softer tube material and a lower occlusion for a harder tube material.
   The "Attack" control is used to define the length of time the gate takes to change from closed to fully open. It is the fade-in duration.
  
  The "Hold" control is used to define the length of time the gate will stay fully open after the signal falls below the threshold, and before the Release period is commenced. The hold control is often set to ensure the gate does not close during short pauses between words or sentences in a speech signal.
   This is done by using concentric bellows counterlungs – the counterlung is configured as a bellows with a rigid top and bottom, and has a flexible corrugated membrane forming the side walls. There is a second, smaller bellows inside, also connected to the rigid top and bottom surfaces of the counterlung, so that as the rigid surfaces move towards and away from each other, the volumes of the inner and outer bellows change in the same proportion.
   There are several types of fast-opening doors commonly used. The simplest and most primitive type of door, a bolted plate or flanged cap on some sort of hinge, is no longer considered even minimally acceptable for production autoclaves because it is anything but quick in opening and closing. For vessels up to four feet in diameter and rated at not much over 125 psi, a hinged semi-elliptical door secured by lever-operated cam-locking T-bolts works essentially as quickly and as easily as the more commonly used rotating locking ring door. This door design uses up to a dozen or so latching T-bolts on the door hub (see photos), the stationary part fitted to the cylindrical vessel itself, which engage matching lugs welded to the door. When the operating levers are rotated over center, the T-bolts draw the lugs closer and seal the door by means of an O-ring gasket.
   Expressions can exhibit a force dynamic pattern or can be force-dynamically neutral. A sentence like "The door is closed" is force-dynamically neutral, because there are no forces opposing each other. The sentence "The door cannot open", on the other hand, exhibits a force dynamic pattern: apparently the door has some tendency toward opening, but there is some other force preventing it from being opened (e.g., it may be jammed).
   BULLET::::- The 2000 film "The 6th Day", features an internet refrigerator which informs Arnold Schwarzenegger that the milk is over its expiring date and asks him to confirm a new order.
  
  BULLET::::- The 2004 film "The Stepford Wives", features a smart fridge that can tell whenever it has no juice, etc. in Joanna's new Stepford home.
  
  BULLET::::- The 2012 film "Total Recall", features a smart refrigerator that is covered by a touchscreen which enables the user to leave notes and messages.
  