How do CPAP Machines Maintain Pressure?

Hello, can someone tell me how pressure is maintained with a CPAP or have links to an explanation?

I want to know if there's any pressure regulation? Variable flow or if displacement is fixed? Etc...

Aside from being a curious engineer, I want to know how seriously to take small leaks as well as concern over just changing masks arbitrarily.

Different machines use different hardware, and different firmware algorithms to do that. You're probably interested in your own machine.
dsm - a member has take apart a number of them - take a peek here http://www.internetage.com/cpapinfo/index.html.

Until some of our engineer member add their updated info, you can do a search for words like "impeller" and "transducer" and you'll find some interesting stuff.

O.

john_dozer wrote:Hello, can someone tell me how pressure is maintained with a CPAP or have links to an explanation?

I want to know if there's any pressure regulation? Variable flow or if displacement is fixed? Etc...

Aside from being a curious engineer, I want to know how seriously to take small leaks as well as concern over just changing masks arbitrarily.

There are sensors built into the circuits to monitor and adjust the airflow to guarantee that the specified amount of pressure is maintained. Most/all of the "data-capable" machines (CPAPs and APAPs) have these features (including auto-adjusting altitude compensation).

However......
IF you were wondering about your own machine......it doesn't have "leak compensation" or "auto-adjusting altitude compensation" and hence would not be able to guarantee a specified amount of pressure during a leaky night.

Den

https://www.cpap.com/cpap-machine/S8-Compact-CPAP.html

Compare Chart Specifications
Can Be Worn: No
Manufacturer: Resmed
4-20 Cm: Yes
Pressure Relief on Exhale: No
Integrated Heated Hose: No
Domestic Voltage-110: Yes
International Voltage-220: Yes
Optional DC Cable: No
Direct Battery Operation: No
Integrated Battery: No
Auto Altitude Adjustment: Manual Adjustment
Ramp: Yes
Hour/Session: Yes
Optional Software: No
Leak Compensation: No
Heated Humidifier: H3i
Passover Humidifier: Passover (Any)
Data Card: No
Auto ON/OFF: No
Warranty: 2 Years
Mask Off Alert: No
Machine Weight: 2.9 lbs
Entire Weight: 4.5 lbs
Entire Size: 12" x 5" x 4"
Entire Package Size: 8" x 7.5" x 8"
Manuals Included: Patient/Quick Setup
Sound Level: 31-dB

Other Specifications

* Operating Pressure Range (Manual Alititude Adjustment), 4-20 cm H20
* Data Storage, Used hours and usage days available from flow generator.
* Dimensions (H x W x D), 4.6 in x 6.5 in x 5.7 in (112 mm x 164 mm x 145 mm)
* Weight, Flow generator: 2.9 lbs (1.3 kg)
* Power Supply Input Range, 100-240V AC, 50/60 Hz
* Housing Construction, flame retardant engineering thermoplastic
* Environmental conditions, Operating Temperature +41 to +104 Degrees F (+5 to +40 Degrees C)
* Air Filter, Two-layered, powder-bonded polyester non-woven fiber
* Air Tubing, Flexible plastic, 6'6" (2m) length

Well, inside is a rat, mounted inside a small wheel, the wheel is a running a belt that drives a fan. The fan when turning forces the moving air, against a leaf that has a rod attached to it, that pushs the sharp end of the rod into the rats side. The pressure is controlled by adjusting the tension on springs attached to both sides of the leaf.

When turned off the springs balance, the rod pulls away from the rat and he stops running. Turning it on pulls the spring attached to the leaf, the rat gets poked and starts running. When the rat gets the air flow fast enough to overcome the the spring tension (Treatment Pressure), the stick stops pushing painfully into the rat, and he maintains the pace to keep from getting poked harder.

Different models have more elaborate methods for controlling XPAP pressure, but this is the method used in most DME starter machines. Jim

Thanks all for the input.

Thanks for the specifics on my machine that helps explain why problems with mask leaks are undermining my therapy so easily. (should have clicked on my own info )