Backup rate

Time trigger The ventilator initiates a breath according to a set frequency or time. This is commonly referred to as the backup rate. Knowing the range a ventilator has for a backup rate can be important while choosing a machine, especially for pediatrics. 

Manufacturer and product name Picture Inspiratory trigger variable V = multiple sensitivity settings Backup rate min and max Inspiratory limit variable(s)... 

In France, most patients receiving HMV only use machines equipped with a backup rate, whereas in some countries, unless it can be shown that a patient is poorly ventilated without a backup rate, an assist-only device is prescribed. We have frequently monitored patients ventilated at home and observed that many of them breathe at the backup rate, regardless of where it is set. There is limited information as to how many patients require a backup rate versus assist-only devices. In one small study, 15% required backup after titration using polysomnography (6). 

Increasing the rate is also a strategy for increasing minute ventilation in a passive patient, which could allow the level of pressure support to be maintained at a lower level, limiting mask leak. The range of backup rates available for each ventilator can be found in... 

EPAP/PEEP Rise time Backup rate Inspiratory trigger Expiratory trigger/cycle... 

In my opinion, the prevalent misconception of the progression of immobility as the signal for end-of-life care is the reason morphine sulfate and oxygen were given as a substitute for NPPV. I observed that these two treatments were often administered by hospices in successful users of NPPV. This was based on their perspective that since ALS is fatal, and that their protocols are the treatment of choice, rather than the optimal use of NPPV and airway clearance. In addition, some hospices consider that NPPV should be used intermittently to provide comfort only and not to extend survival. Furthermore, the use of bi-level ventilators by hospices, without backup rates, has increased for ALS patients. The hospice nurses had based their opinion on the belief that backup rates promote survival and had not understood that a backup is necessary for optimal relief of h)rpoventilation. 

Downflow Flooding Columns can flood because of their inability to handle large quantities of liqmd. For crossbow plates this hmit on liquid rate Is evidenced by downcomer backup to the plate above. To avoid downflow flooding one must size the column downcomers such that excessive backup does not occur. 

For larger diameter columns, and for low liquid rates, the distributor must be almost exactly level (e.g., within 6 mm for a 3-m diameter) or all pour points will not function. On the other hand, the rises must be high enough to accommodate the backup caused by high liquid rates. The needed head can be estimated from the orifice equation, with a discharge coefficient of 0.5. In some cases the orinces discharge directly into tubes that extend to the packed bed (the Tubed drip-pan distributor ). 

In a countercurrent-type column contactor, stable operation is possible as long as the rate of arrival of droplets in any section does not exceed the coalescence rate at the main interface once this value is exceeded, droplet backup will occur at the interface and slowly build back into the column active area, a condition known as flooding. This is an inoperable condition. 

A breaker, usually an MCCB or an MCB on an LT system, can be provided with backup HRC fuses to enhance their short-time rating. This may be done when the available MCCBs or MCBs possess a lower short-time rating than the fault level of the circuit they are required to protect, and make them suitable for the fault level of the circuit. But this is not a preferred practice and is seldom used. As a rule of thumb, the device that is protecting must be suitable to withstand electrically and endure mechanically the system fault current for a duration of one or three seconds, according to the system design. 

The turboexpander lowers the temperature of the product to -100°F, causing it to liquify. Now at 350 psig pressure, the liquid from this process enters the demethanizer tower where it mingles with the previously introduced stream of liquid. The turboexpanders provide a 92% recovery rate while the former system, a backup Joule-Thomson valve, was able to provide only a 60% recovery rate. The volume of gas entering the turboexpanders can vary up to 10% yet, the different flowrates do not significantly affect the efficiency of these units, which are rated at 2,400 hp at 16,000 rpm. 

A critical installation should have the metal temperature sensors in the thrust pad. Axial proximity probes may be used as a backup system. If metal temperatures are high and the rate of change of those temperatures begins to alter rapidly, thrust-bearing failure should be anticipated. 

It is very important that the inert gas be available from a reliable source and that the proper pressure and flow rate are always provided. A low-pressure switch and alarm are sometimes installed in the inert gas supply line to the equipment and piping. The alarm will warn the operator that a problem may be occurring with the inert gas supply. The switch is also sometimes interlocked to open up a valve in piping from a backup inert gas cylinder bank. 

Gas turbines operate on natural gas, synthetic gas, landfill gas, and fuel oils. Plants are often designed to operate on gaseous fuel with a stored liquid fuel for backup, so as to obtain the less-expensive interruptible rate for natural gas. Dual fuel combustion capability is a purchase option on many gas turbines. The turbine is ideally suited as an integral component in the IGCC train. Further, modern gas turbines have proven to be reliable power generators, given proper maintenance. Time to overhaul is typically 25,000 to 50,000... 

This work has demonstrated that sorbent tubes are viable samplers for inorganic acid mists existing as vapors and aerosols. A silica gel sampling tube was developed which will collect at least a 4-hour sample of inorganic acid at a nominal flow rate of 0.2 Lpm. The optimum sampler geometry was determined to be a 7-mm O.D./4.8-mm I.D. glass tube packed with 20-40 mesh washed silica gel, 700 mg in the primary section and 200 mg in the backup. 

The collection efficiency of a filter sampler was demonstrated by sampling test atmospheres with a backup collector at the proposed sampling rate and time, and analyzing the collected samples. For sorbents or filter/sorbent sampling trains, the breakthrough volume was determined (to demonstrate capacity) at 80% relative humidity. 6... 

A glass tube (6-mm I.D. by 8-mm O.D. by 3-cm long) is packed with approximately 100 mg of sorbent in a front section and 50 mg in a backup section, each separated by glass wool plugs. Sorbents of coarse mesh size ( 20/40) are used to minimize the pressure drop across the tube. A calibrated personal sampling pump draws air through the sorbent tube at a flow rate of up to 1 liter/min. 

See Figure 5.) The sampling rate of the backup section is a function of the total area and length through which the contaminant must travel from the front face of the badge to the backup section charcoal strip. This sampling rate can be determined by the use of equation (3)(14). 

Since the of the backup section is 2.2 times the of the front section, the backup section should sample additional material at 46 percent of the sampling rate of the front section. (See Figure 3.)... 

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