The phrase "apparatus that allows" is correct and usable in written English.
It can be used when describing a device or system that enables a specific function or capability.
Example: "The new apparatus that allows for faster data processing has been implemented in our lab."
Alternatives: "device that enables" or "system that permits".
To measure velocity, by contrast, we need an apparatus that allows for some recoil, and hence moveable parts.
Under the Trump Administration, the diplomatic apparatus that allows the U.S. to communicate with its allies and its enemies alike has been taking "a nosedive".
Musser takes us into the lab of the Colgate professor Enrique Galvez, who has constructed a simple apparatus that allows him to entangle photons and then show that "the photons are behaving like a pair of magic coins. . .
There are more amenities, however – when they break into their quarry's hotel room, they discover an apparatus that allows them to talk to the front desk by means of a "large black horn emerging from the wall beside the bed".
There is also a goofy apparatus that allows you to scan the bar codes of cosmetics, and then on a monitor shows you an image of yourself wearing those items (and looking like a drag queen).
Musser takes us into the lab of the Colgate professor Enrique Galvez, who has constructed a simple apparatus that allows him to entangle photons and then show that "the photons are behaving like a pair of magic coins.
These devices, which generate vapour trails that mark the passage of high-energy subatomic particles, were the first apparatus that allowed such passage to be tracked.
The monomer was pre-dispersed by using a high-speed homogenizer apparatus that allowed use mild agitation conditions during the polymerization.
This method was based on a heat balance in the steady state between the sample and the three disks of the apparatus that allowed us to calculate the thermal resistivity of the solid sample.
The flow through fracture of Non-Newtonian suspensions was studied using an apparatus that allowed these fluids to flow through three different artificial fractures with widths of 2 mm, 5 mm and 10 mm and an average 1 cm depth.
A mouse was attached by the tail to a horizontally mounted force transducer using suture silk and subsequently placed in an apparatus that allowed only forward movement.
